Science.gov

Sample records for pv large systems

  1. PV large systems project

    NASA Technical Reports Server (NTRS)

    Leonard, S. L.

    1982-01-01

    Near term photovoltaic central-station markets are analyzed. Cost effectiveness of photovoltaic plants is determined in terms of reduction of oil consumption. The breakeven photovoltaic system cost vs oil-steam power generation is given. The value of photovoltaic power plants in Southern California and in Los Angelos is given in terms of fuel savings and capacity value. The potential value of third party financing, facilitated by Federal and state tax incentives is analyzed.

  2. High power/large area PV systems

    NASA Technical Reports Server (NTRS)

    Wise, Joseph; Baraona, Cosmo

    1987-01-01

    The major photovoltaic power system technology drivers for a wide variety of mission types were ranked. Each technology driver was ranked on a scale of high, medium, or low in terms of importance to each particular mission type. The rankings were then compiled to determine the overall importance of each driver over the entire range of space missions. In each case cost was ranked the highest.

  3. Output Control Technologies for a Large-scale PV System Considering Impacts on a Power Grid

    NASA Astrophysics Data System (ADS)

    Kuwayama, Akira

    The mega-solar demonstration project named “Verification of Grid Stabilization with Large-scale PV Power Generation systems” had been completed in March 2011 at Wakkanai, the northernmost city of Japan. The major objectives of this project were to evaluate adverse impacts of large-scale PV power generation systems connected to the power grid and develop output control technologies with integrated battery storage system. This paper describes the outline and results of this project. These results show the effectiveness of battery storage system and also proposed output control methods for a large-scale PV system to ensure stable operation of power grids. NEDO, New Energy and Industrial Technology Development Organization of Japan conducted this project and HEPCO, Hokkaido Electric Power Co., Inc managed the overall project.

  4. Optimal Planning Strategy for Large PV/Battery System Based on Long-Term Insolation Forecasting

    NASA Astrophysics Data System (ADS)

    Yona, Atsushi; Uchida, Kosuke; Senjyu, Tomonobu; Funabashi, Toshihisa

    Photovoltaic (PV) systems are rapidly gaining acceptance as some of the best alternative energy sources. Usually the power output of PV system fluctuates depending on weather conditions. In order to control the fluctuating power output for PV system, it requires control method of energy storage system. This paper proposes an optimization approach to determine the operational planning of power output for PV system with battery energy storage system (BESS). This approach aims to obtain more benefit for electrical power selling and to smooth the fluctuating power output for PV system. The optimization method applies genetic algorithm (GA) considering PV power output forecast error. The forecast error is based on our previous works with the insolation forecasting at one day ahead by using weather reported data, fuzzy theory and neural network(NN). The validity of the proposed method is confirmed by the computer simulations.

  5. Large-area, high-intensity PV arrays for systems using dish concentrating optics

    SciTech Connect

    Ward, J.S.; Duda, A.; Zweibel, K.; Coutts, T.J.

    1998-09-01

    In this paper, the authors report on efforts to fabricate monolithic interconnected modules (MIMs) using III-V semiconductors with bandgaps appropriate for the terrestrial solar spectrum. The small size of the component cells comprising the MIM allows for operation at extremely high flux densities and relaxes the requirement for a small spot size to be generated by the optics. This makes possible a PV option for the large dish concentrator systems that have been developed by the solar thermal community for use with Stirling engines. Additionally, the highly effective back-surface reflector integrated into the MIM design is an effective tool for thermal management of the array. Development of this technology would radically alter the projections for PV manufacturing capacity because of the potential for extremely high power generation per unit area of semiconductor material.

  6. Design of energy storage system to improve inertial response for large scale PV generation

    DOE PAGES

    Wang, Xiaoyu; Yue, Meng

    2016-07-01

    With high-penetration levels of renewable generating sources being integrated into the existing electric power grid, conventional generators are being replaced and grid inertial response is deteriorating. This technical challenge is more severe with photovoltaic (PV) generation than with wind generation because PV generation systems cannot provide inertial response unless special countermeasures are adopted. To enhance the inertial response, this paper proposes to use battery energy storage systems (BESS) as the remediation approach to accommodate the degrading inertial response when high penetrations of PV generation are integrated into the existing power grid. A sample power system was adopted and simulated usingmore » PSS/E software. Here, impacts of different penetration levels of PV generation on the system inertial response were investigated and then BESS was incorporated to improve the frequency dynamics.« less

  7. Design of energy storage system to improve inertial response for large scale PV generation

    SciTech Connect

    Wang, Xiaoyu; Yue, Meng

    2016-07-01

    With high-penetration levels of renewable generating sources being integrated into the existing electric power grid, conventional generators are being replaced and grid inertial response is deteriorating. This technical challenge is more severe with photovoltaic (PV) generation than with wind generation because PV generation systems cannot provide inertial response unless special countermeasures are adopted. To enhance the inertial response, this paper proposes to use battery energy storage systems (BESS) as the remediation approach to accommodate the degrading inertial response when high penetrations of PV generation are integrated into the existing power grid. A sample power system was adopted and simulated using PSS/E software. Here, impacts of different penetration levels of PV generation on the system inertial response were investigated and then BESS was incorporated to improve the frequency dynamics.

  8. Design of energy storage system to improve inertial response for large scale PV generation

    SciTech Connect

    Wang, Xiaoyu; Yue, Meng

    2016-07-01

    With high-penetration levels of renewable generating sources being integrated into the existing electric power grid, conventional generators are being replaced and grid inertial response is deteriorating. This technical challenge is more severe with photovoltaic (PV) generation than with wind generation because PV generation systems cannot provide inertial response unless special countermeasures are adopted. To enhance the inertial response, this paper proposes to use battery energy storage systems (BESS) as the remediation approach to accommodate the degrading inertial response when high penetrations of PV generation are integrated into the existing power grid. A sample power system was adopted and simulated using PSS/E software. Here, impacts of different penetration levels of PV generation on the system inertial response were investigated and then BESS was incorporated to improve the frequency dynamics.

  9. Large-Scale PV Integration Study

    SciTech Connect

    Lu, Shuai; Etingov, Pavel V.; Diao, Ruisheng; Ma, Jian; Samaan, Nader A.; Makarov, Yuri V.; Guo, Xinxin; Hafen, Ryan P.; Jin, Chunlian; Kirkham, Harold; Shlatz, Eugene; Frantzis, Lisa; McClive, Timothy; Karlson, Gregory; Acharya, Dhruv; Ellis, Abraham; Stein, Joshua; Hansen, Clifford; Chadliev, Vladimir; Smart, Michael; Salgo, Richard; Sorensen, Rahn; Allen, Barbara; Idelchik, Boris

    2011-07-29

    This research effort evaluates the impact of large-scale photovoltaic (PV) and distributed generation (DG) output on NV Energy’s electric grid system in southern Nevada. It analyzes the ability of NV Energy’s generation to accommodate increasing amounts of utility-scale PV and DG, and the resulting cost of integrating variable renewable resources. The study was jointly funded by the United States Department of Energy and NV Energy, and conducted by a project team comprised of industry experts and research scientists from Navigant Consulting Inc., Sandia National Laboratories, Pacific Northwest National Laboratory and NV Energy.

  10. PV System Performance and Standards

    SciTech Connect

    Osterwald, C. R.

    2005-11-01

    This paper presents a brief overview of the status and accomplishments during fiscal year (FY) 2005 of the Photovoltaic (PV) System Performance and Standards Subtask, which is part of the PV Systems Engineering Project (a joint NREL-Sandia project).

  11. PV system field experience and reliability

    NASA Astrophysics Data System (ADS)

    Durand, Steven; Rosenthal, Andrew; Thomas, Mike

    1997-02-01

    Hybrid power systems consisting of battery inverters coupled with diesel, propane, or gasoline engine-driven electrical generators, and photovoltaic arrays are being used in many remote locations. The potential cost advantages of hybrid systems over simple engine-driven generator systems are causing hybrid systems to be considered for numerous applications including single-family residential, communications, and village power. This paper discusses the various design constraints of such systems and presents one technique for reducing hybrid system losses. The Southwest Technology Development Institute under contract to the National Renewable Energy Laboratory and Sandia National Laboratories has been installing data acquisition systems (DAS) on a number of small and large hybrid PV systems. These systems range from small residential systems (1 kW PV - 7 kW generator), to medium sized systems (10 kW PV - 20 kW generator), to larger systems (100 kW PV - 200 kW generator). Even larger systems are being installed with hundreds of kilowatts of PV modules, multiple wind machines, and larger diesel generators.

  12. PV system testing and standards

    NASA Astrophysics Data System (ADS)

    DeBlasio, Richard

    1999-03-01

    The U.S. Department of Energy (DOE) PV Program System Performance and Engineering Project is being conducted by The National Renewable Energy Laboratory (NREL), Sandia National Laboratories (SNL), Southwest Technology Development Institute (SWTDI), and Florida Solar Energy Center (FSEC). It provides PV system, subsystem, and component-level technology-performance characterization testing; test-method development and validation; national and international consensus standards and codes development, test-facility product certification, and laboratory-accreditation program implementation; and information exchange and technical assistance to the PV community. Emphasis is placed on reducing technical and infrastructural barriers to system acceptance, reducing life-cycle cost of systems, providing systems-engineering best practices and guidelines, and leading the national effort in performance and reliability testing, and consensus standards, codes, and certification program development and implementation—thereby ensuring that PV systems meet customers' needs and expectations. A summary of project activities, accomplishments, and future plans is provided and highlighted by an overview of PV system test-procedure and standards development.

  13. PV Systems Reliability Final Technical Report.

    SciTech Connect

    Lavrova, Olga; Flicker, Jack David; Johnson, Jay; Armijo, Kenneth Miguel; Gonzalez, Sigifredo; Schindelholz, Eric John; Sorensen, Neil R.; Yang, Benjamin Bing-Yeh

    2015-12-01

    The continued exponential growth of photovoltaic technologies paves a path to a solar-powered world, but requires continued progress toward low-cost, high-reliability, high-performance photovoltaic (PV) systems. High reliability is an essential element in achieving low-cost solar electricity by reducing operation and maintenance (O&M) costs and extending system lifetime and availability, but these attributes are difficult to verify at the time of installation. Utilities, financiers, homeowners, and planners are demanding this information in order to evaluate their financial risk as a prerequisite to large investments. Reliability research and development (R&D) is needed to build market confidence by improving product reliability and by improving predictions of system availability, O&M cost, and lifetime. This project is focused on understanding, predicting, and improving the reliability of PV systems. The two areas being pursued include PV arc-fault and ground fault issues, and inverter reliability.

  14. Leasing Residential PV Systems

    SciTech Connect

    Rutberg, Michael; Bouza, Antonio

    2013-11-01

    The article discusses the adoption, consequences and current market status of the leasing of residential photovoltaic systems. It addresses attributed energy savings and market potential of residential system leasing.

  15. Cascaded Microinverter PV System for Reduced Cost

    SciTech Connect

    Bellus, Daniel R.; Ely, Jeffrey A.

    2013-04-29

    In this project, a team led by Delphi will develop and demonstrate a novel cascaded photovoltaic (PV) inverter architecture using advanced components. This approach will reduce the cost and improve the performance of medium and large-sized PV systems. The overall project objective is to develop, build, and test a modular 11-level cascaded three-phase inverter building block for photovoltaic applications and to develop and analyze the associated commercialization plan. The system will be designed to utilize photovoltaic panels and will supply power to the electric grid at 208 VAC, 60 Hz 3-phase. With the proposed topology, three inverters, each with an embedded controller, will monitor and control each of the cascade sections, reducing costs associated with extra control boards. This report details the final disposition on this project.

  16. 46 CFR 153.355 - PV venting systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false PV venting systems. 153.355 Section 153.355 Shipping... Systems § 153.355 PV venting systems. When Table 1 requires a PV venting system, the cargo tank must have a PV valve in its vent line. The PV valve must be located between the tank and any connection to...

  17. 46 CFR 153.355 - PV venting systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false PV venting systems. 153.355 Section 153.355 Shipping... Systems § 153.355 PV venting systems. When Table 1 requires a PV venting system, the cargo tank must have a PV valve in its vent line. The PV valve must be located between the tank and any connection to...

  18. A High Efficiency DC-DC Converter Topology Suitable for Distributed Large Commercial and Utility Scale PV Systems

    SciTech Connect

    Agamy, Mohammed S; Harfman-Todorovic, Maja; Elasser, Ahmed; Steigerwald, Robert L; Sabate, Juan A; Chi, Song; McCann, Adam J; Zhang, Li; Mueller, Frank

    2012-09-01

    In this paper a DC-DC power converter for distributed photovoltaic plant architectures is presented. The proposed converter has the advantages of simplicity, high efficiency, and low cost. High efficiency is achieved by having a portion of the input PV power directly fed forward to the output without being processed by the converter. The operation of this converter also allows for a simplified maximum power point tracker design using fewer measurements

  19. Interconnecting PV on New York City's Secondary Network Distribution System

    SciTech Connect

    Anderson, K; Coddington, M; Burman, K; Hayter, S; Kroposki, B; Watson, and A

    2009-11-01

    The U.S. Department of Energy (DOE) has teamed with cities across the country through the Solar America Cities (SAC) partnership program to help reduce barriers and accelerate implementation of solar energy. The New York City SAC team is a partnership between the City University of New York (CUNY), the New York City Mayor s Office of Long-term Planning and Sustainability, and the New York City Economic Development Corporation (NYCEDC).The New York City SAC team is working with DOE s National Renewable Energy Laboratory (NREL) and Con Edison, the local utility, to develop a roadmap for photovoltaic (PV) installations in the five boroughs. The city set a goal to increase its installed PV capacity from1.1 MW in 2005 to 8.1 MW by 2015 (the maximum allowed in 2005). A key barrier to reaching this goal, however, is the complexity of the interconnection process with the local utility. Unique challenges are associated with connecting distributed PV systems to secondary network distribution systems (simplified to networks in this report). Although most areas of the country use simpler radial distribution systems to distribute electricity, larger metropolitan areas like New York City typically use networks to increase reliability in large load centers. Unlike the radial distribution system, where each customer receives power through a single line, a network uses a grid of interconnected lines to deliver power to each customer through several parallel circuits and sources. This redundancy improves reliability, but it also requires more complicated coordination and protection schemes that can be disrupted by energy exported from distributed PV systems. Currently, Con Edison studies each potential PV system in New York City to evaluate the system s impact on the network, but this is time consuming for utility engineers and may delay the customer s project or add cost for larger installations. City leaders would like to streamline this process to facilitate faster, simpler, and

  20. PV System Energy Evaluation Method (Presentation)

    SciTech Connect

    Kurtz, S.

    2014-01-01

    This presentation describes a comparison of the "predicted" energy (based on historical weather data) with the "expected" energy (based on the measured weather data) to determine whether a PV system is performing as modeled in order to verify the accuracy of a model. A key factor in defining this energy test is determining the test boundary so that weather variations are not inadvertently included in what is considered to be PV system performance.

  1. High Penetration PV Deployment in the Arizona Public Service System

    SciTech Connect

    Narang, D.; Hambrick, J.

    2011-01-01

    In an effort to better understand the impacts of high penetrations of photovoltaic (PV) generators on distribution systems, Arizona Public Service (APS) and its partners have begun work on a multi-year project to develop the tools and knowledgebase needed to safely and reliably integrate high penetrations of utility and residential scale PV. Building upon the APS Community Power Project - Flagstaff Pilot, this project will analyze the impact of PV on a representative feeder in northeast Flagstaff. To quantify and catalog the effects of the estimated 1.5 MW of PV that will be installed on the feeder (both smaller units at homes as well as large, centrally located systems), high-speed weather and electrical data acquisition systems and digital 'smart' meters are being designed and installed to facilitate monitoring and to build and validate comprehensive, high-resolution models of the distribution system. These models will be used to analyze the impacts of the PV on distribution circuit protection systems (including anti-islanding), predict voltage regulation and phase balance issues, and develop volt/var control schemes. The goal of this paper is to provide insight and lessons learned on the early stages of high penetration PV deployment. Primarily focusing on modeling and data acquisition, this paper describes the overall project, early results, and plans for future phases of the project.

  2. Residential Solar PV Systems in the Carolinas: Opportunities and Outcomes.

    PubMed

    Alqahtani, Bandar Jubran; Holt, Kyra Moore; Patiño-Echeverri, Dalia; Pratson, Lincoln

    2016-02-16

    This paper presents a first-order analysis of the feasibility and technical, environmental, and economic effects of large levels of solar photovoltaic (PV) penetration within the services areas of the Duke Energy Carolinas (DEC) and Duke Energy Progress (DEP). A PV production model based on household density and a gridded hourly global horizontal irradiance data set simulates hourly PV power output from roof-top installations, while a unit commitment and real-time economic dispatch (UC-ED) model simulates hourly system operations. We find that the large generating capacity of base-load nuclear power plants (NPPs) without ramping capability in the region limits PV integration levels to 5.3% (6510 MW) of 2015 generation. Enabling ramping capability for NPPs would raise the limit of PV penetration to near 9% of electricity generated. If the planned retirement of coal-fired power plants together with new installations and upgrades of natural gas and nuclear plants materialize in 2025, and if NPPs operate flexibly, then the share of coal-fired electricity will be reduced from 37% to 22%. A 9% penetration of electricity from PV would further reduce the share of coal-fired electricity by 4-6% resulting in a system-wide CO2 emissions rate of 0.33 to 0.40 tons/MWh and associated abatement costs of 225-415 (2015$ per ton).

  3. Rating PV Power and Energy: Cell, Module, and System Measurements

    SciTech Connect

    Emery, Keith

    2016-06-02

    A summary of key points related to research-level measurements of current vs. voltage measurement theory including basic PV operation, equivalent circuit, and concept of spectral error; PV power performance including PV irradiance sensors, simulators and commercial and generic I-V systems; PV measurement artifacts, intercomparisons, and alternative rating methods.

  4. Active power control of solar PV generation for large interconnection frequency regulation and oscillation damping

    SciTech Connect

    Liu, Yong; Zhu, Lin; Zhan, Lingwei; Gracia, Jose R.; King, Thomas Jr.; Liu, Yilu

    2015-06-23

    Because of zero greenhouse gas emission and decreased manufacture cost, solar photovoltaic (PV) generation is expected to account for a significant portion of future power grid generation portfolio. Because it is indirectly connected to the power grid via power electronic devices, solar PV generation system is fully decoupled from the power grid, which will influence the interconnected power grid dynamic characteristics as a result. In this study, the impact of solar PV penetration on large interconnected power system frequency response and inter-area oscillation is evaluated, taking the United States Eastern Interconnection (EI) as an example. Furthermore, based on the constructed solar PV electrical control model with additional active power control loops, the potential contributions of solar PV generation to power system frequency regulation and oscillation damping are examined. The advantages of solar PV frequency support over that of wind generator are also discussed. Finally, simulation results demonstrate that solar PV generations can effectively work as ‘actuators’ in alleviating the negative impacts they bring about.

  5. Active power control of solar PV generation for large interconnection frequency regulation and oscillation damping

    DOE PAGES

    Liu, Yong; Zhu, Lin; Zhan, Lingwei; ...

    2015-06-23

    Because of zero greenhouse gas emission and decreased manufacture cost, solar photovoltaic (PV) generation is expected to account for a significant portion of future power grid generation portfolio. Because it is indirectly connected to the power grid via power electronic devices, solar PV generation system is fully decoupled from the power grid, which will influence the interconnected power grid dynamic characteristics as a result. In this study, the impact of solar PV penetration on large interconnected power system frequency response and inter-area oscillation is evaluated, taking the United States Eastern Interconnection (EI) as an example. Furthermore, based on the constructedmore » solar PV electrical control model with additional active power control loops, the potential contributions of solar PV generation to power system frequency regulation and oscillation damping are examined. The advantages of solar PV frequency support over that of wind generator are also discussed. Finally, simulation results demonstrate that solar PV generations can effectively work as ‘actuators’ in alleviating the negative impacts they bring about.« less

  6. Real time PV manufacturing diagnostic system

    SciTech Connect

    Kochergin, Vladimir; Crawford, Michael A.

    2015-09-01

    The main obstacle Photovoltaic (PV) industry is facing at present is the higher cost of PV energy compared to that of fossil energy. While solar cell efficiencies continue to make incremental gains these improvements are so far insufficient to drive PV costs down to match that of fossil energy. Improved in-line diagnostics however, has the potential to significantly increase the productivity and reduce cost by improving the yield of the process. On this Phase I/Phase II SBIR project MicroXact developed and demonstrated at CIGS pilot manufacturing line a high-throughput in-line PV manufacturing diagnostic system, which was verified to provide fast and accurate data on the spatial uniformity of thickness, an composition of the thin films comprising the solar cell as the solar cell is processed reel-to-reel. In Phase II project MicroXact developed a stand-alone system prototype and demonstrated the following technical characteristics: 1) ability of real time defect/composition inconsistency detection over 60cm wide web at web speeds up to 3m/minute; 2) Better than 1mm spatial resolution on 60cm wide web; 3) an average better than 20nm spectral resolution resulting in more than sufficient sensitivity to composition imperfections (copper-rich and copper-poor regions were detected). The system was verified to be high vacuum compatible. Phase II results completely validated both technical and economic feasibility of the proposed concept. MicroXact’s solution is an enabling technique for in-line PV manufacturing diagnostics to increase the productivity of PV manufacturing lines and reduce the cost of solar energy, thus reducing the US dependency on foreign oil while simultaneously reducing emission of greenhouse gasses.

  7. Radiometric instrumentation for PV system performance monitoring

    SciTech Connect

    Stoffel, T.

    1995-09-01

    This paper provides an overview of existing instrumentation options and solicits user needs for improving outdoor solar radiation measurements for determining PV system performance. The following topics are discussed: (1) historical overview and terminology; (2) radiometer calibration and characterization methods used by NREL; (3) sample calibration results for various commercial instruments; (4) current research topics; (5) user needs for improved PV performance monitoring. Emphasis is placed on the need for the user to understand the measurement capabilities of commercially available radiometers and interpret the measurement results accordingly. A list of radiometer manufacturers is also provided.

  8. Updating Interconnection Screens for PV System Integration

    SciTech Connect

    Coddington, M.; Mather, B.; Kroposki, B.; Lynn, K.; Razon, A.; Ellis, A.; Hill, R.; Key, T.; Nicole, K.; Smith, J.

    2012-02-01

    This white paper evaluates the origins and usefulness of the capacity penetration screen, offer short-term solutions which could effectively allow fast-track interconnection to many PV system applications, and considers longer-term solutions for increasing PV deployment levels in a safe and reliable manner while reducing or eliminating the emphasis on the penetration screen. Short-term and longer-term alternatives approaches are offered as examples; however, specific modifications to screening procedures should be discussed with stakeholders and must ultimately be adopted by state and federal regulatory bodies.

  9. Determination of Parameters of PV Concentrating System With Heliostat

    NASA Astrophysics Data System (ADS)

    Vardanyan, R.; Norsoyan, A.; Dallakyan, V.

    2010-10-01

    The structure of PV concentrating system with heliostat is analyzed. The mathematical model of system consisting of PV concentrating module and heliostat is developed. With the use of developed mathematical model the optimal parameters of the system are determined. The results of this work can be used during the design of PV concentrating systems with heliostats.

  10. A new flexible a-Si PV module and its application to rooftop PV systems

    SciTech Connect

    Ichikawa, Yukimi; Ihara, Takuro; Hama, Toshio

    1994-12-31

    A novel photovoltaic (PV) module for roof top systems, solar roofing, was proposed. Solar roofing is a flexible amorphous silicon (a-Si) PV sheet having the function of roofing. Tempered glass is used as roof covering material. Technical items for roof top systems using solar roofing were discussed. Preliminary studies on module component materials showed feasibility of solar roofing. The authors designed a construction technology for tempered glass covered roofs. Effects of shadows on PV module upon its performance were also analyzed.

  11. The possibility of developing hybrid PV/T solar system

    NASA Astrophysics Data System (ADS)

    Dobrnjac, M.; Zivkovic, P.; Babic, V.

    2017-05-01

    An alternative and cost-effective solution to developing integrated PV system is to use hybrid photovoltaic/thermal (PV/T) solar system. The temperature of PV modules increases due to the absorbed solar radiation that is not converted into electricity, causing a decrease in their efficiency. In hybrid PV/T solar systems the reduction of PV module temperature can be combined with a useful fluid heating. In this paper we present the possibility of developing a new hybrid PV/T solar system. Hybrid PV/T system can provide electrical and thermal energy, thus achieving a higher energy conversion rate of the absorbed solar radiation. We developed PV/T prototype consisted of commercial PV module and thermal panel with our original solution of aluminium absorber with special geometric shapes. The main advantages of our combined PV/T system are: removing of heat from the PV panel; extending the lifetime of photovoltaic cells; excess of the removing heat from PV part is used to heat the fluid in the thermal part of the panel; the possibility of using on the roof and facade constructions because less weight.

  12. Integrating Solar PV in Utility System Operations

    SciTech Connect

    Mills, A.; Botterud, A.; Wu, J.; Zhou, Z.; Hodge, B-M.; Heany, M.

    2013-10-31

    This study develops a systematic framework for estimating the increase in operating costs due to uncertainty and variability in renewable resources, uses the framework to quantify the integration costs associated with sub-hourly solar power variability and uncertainty, and shows how changes in system operations may affect these costs. Toward this end, we present a statistical method for estimating the required balancing reserves to maintain system reliability along with a model for commitment and dispatch of the portfolio of thermal and renewable resources at different stages of system operations. We estimate the costs of sub-hourly solar variability, short-term forecast errors, and day-ahead (DA) forecast errors as the difference in production costs between a case with “realistic” PV (i.e., subhourly solar variability and uncertainty are fully included in the modeling) and a case with “well behaved” PV (i.e., PV is assumed to have no sub-hourly variability and can be perfectly forecasted). In addition, we highlight current practices that allow utilities to compensate for the issues encountered at the sub-hourly time frame with increased levels of PV penetration. In this analysis we use the analytical framework to simulate utility operations with increasing deployment of PV in a case study of Arizona Public Service Company (APS), a utility in the southwestern United States. In our analysis, we focus on three processes that are important in understanding the management of PV variability and uncertainty in power system operations. First, we represent the decisions made the day before the operating day through a DA commitment model that relies on imperfect DA forecasts of load and wind as well as PV generation. Second, we represent the decisions made by schedulers in the operating day through hour-ahead (HA) scheduling. Peaking units can be committed or decommitted in the HA schedules and online units can be redispatched using forecasts that are improved

  13. International PV QA Task Force's Proposed Comparative Rating System for PV Modules: Preprint

    SciTech Connect

    Wohlgemuth, J.; Kurtz, S.

    2014-10-01

    The International PV Quality Assurance Task Force is developing a rating system that provides comparative information about the relative durability of PV modules. Development of accelerated stress tests that can provide such comparative information is seen as a major step toward being able to predict PV module service life. This paper will provide details of the ongoing effort to determine the format of such an overall module rating system. The latest proposal is based on using three distinct climate zones as defined in IEC 60721-2-1 for two different mounting systems. Specific stresses beyond those used in the qualification tests are being developed for each of the selected climate zones.

  14. Commercialization of PV-powered pumping systems for use in utility PV service programs. Final report

    SciTech Connect

    1997-03-01

    The project described in this report was a commercialization effort focused on cost-effective remote water pumping systems for use in utility-based photovoltaic (PV) service programs. The project combined a commercialization strategy tailored specifically for electric utilities with the development of a PV-powered pumping system that operates conventional ac pumps rather than relying on the more expensive and less reliable PV pumps on the market. By combining these two attributes, a project goal was established of creating sustained utility purchases of 250 PV-powered water pumping systems per year. The results of each of these tasks are presented in two parts contained in this Final Summary Report. The first part summarizes the results of the Photovoltaic Services Network (PSN) as a new business venture, while the second part summarizes the results of the Golden Photon system installations. Specifically, results and photographs from each of the system installations are presented in this latter part.

  15. Photovoltaic (PV) Power Systems for Enhancing Energy Security

    DTIC Science & Technology

    2012-05-24

    Energy and Environment Technology Transition – Supporting DoD Readiness, Sustainability, and the Warfighter Photovoltaic (PV) Power Systems for...to 00-00-2012 4. TITLE AND SUBTITLE Photovoltaic (PV) Power Systems for Enhancing Energy Security 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c...use of 235W solar panels Note [2] System AC Rating based upon typical .77 conversion factor from DC power to AC power ConsiderationNo. PV LAYOUT OPTION

  16. Long-Term Performance of the SERF PV Systems

    SciTech Connect

    Marion, B.; Adelstein, J.

    2003-05-01

    This paper provides the changes in performance ratings of two photovoltaic (PV) systems located on the roof of the Solar Energy Research Facility (SERF) building at the National Renewable Energy Laboratory (NREL) in Golden, Colorado. For the period of May 1994 to April 2002, the performance rating of the two PV systems decreased at the rate of 1% per year. Most of the changes in performance rating are attributed to changes in the performance of the PV arrays. But about a fifth of the observed changes were from the inverter not tracking the peak-power as effectively as the PV arrays aged.

  17. Technical evaluation of a USSC integrated/direct mount PV roofing module system at NREL

    NASA Astrophysics Data System (ADS)

    Strand, T.; Hansen, R.; Mrig, L.

    1996-01-01

    The results of a 16 month technical evaluation performed on a nominal 1 kWac utility-interconnect amorphous silicon PV system deployed at the National Renewable Energy Laboratory's PV outdoor test site are given here. The system employs 64 prototype United Solar Systems Corp. Integrated/Direct Mount PV Roofing Molecules mounted on simulated attic/roof structures. In this paper we show that the PV array fill factor has been relatively stable with respect to time and that the seasonal variations in performance can be largely attributed to seasonal variations in current. We also show that in determining the summer and winter ac power output, the summation of the manufacturer-supplied module peak powers at STC for a similarly located and configured a-Si PV array should be derated by factors of approximately of 0.83 and 0.78 for summer and winter operation, respectively.

  18. Technical evaluation of a USSC Integrated/Direct Mount PV Roofing Module system at NREL

    NASA Astrophysics Data System (ADS)

    Strand, Troy; Hansen, Robert; Mrig, Laxmi

    1995-05-01

    The results of a 16 month technical evaluation performed on a nominal 1 kW(sub ac) utility-interconnect amorphous silicon PV system deployed at the National Renewable Energy Laboratory's PV outdoor test site are given here. The system employs 64 prototype United Solar Systems Corp. Integrated/Direct Mount PV Roofing Modules mounted on simulated attic/roof structures. In this paper we show that the PV array fill factor has been relatively stable with respect to time and that the seasonal variations in performance can be largely attributed to seasonal variations in current. We also show that in determining the summer and winter ac power output, the summation of the manufacturer-supplied module peak powers at STC for a similarly located and configured a-Si PV array should be derated by factors of approximately of 0.83 and 0.78 for summer and winter operation, respectively.

  19. Technical evaluation of a USSC Integrated/Direct Mount PV Roofing Module system at NREL

    SciTech Connect

    Strand, T; Hansen, R; Mrig, L

    1995-05-01

    The results of a 16 month technical evaluation performed on a nominal 1 kW{sub ac} utility-interconnect amorphous silicon PV system deployed at the National Renewable Energy Laboratory`s PV outdoor test site are given here. The system employs 64 prototype United Solar Systems Corp. Integrated/Direct Mount PV Roofing Modules mounted on simulated attic/roof structures. In this paper we show that the PV array fill factor has been relatively stable with respect to time and that the seasonal variations in performance can be largely attributed to seasonal variations in current. We also show that in determining the summer and winter ac power output, the summation of the manufacturer-supplied module peak powers at STC for a similarly located and configured a-Si PV array should be derated by factors of approximately of 0.83 and 0.78 for summer and winter operation, respectively.

  20. Advanced Inverter Technology for High Penetration Levels of PV Generation in Distribution Systems

    SciTech Connect

    Schauder, C.

    2014-03-01

    This subcontract report was completed under the auspices of the NREL/SCE High-Penetration Photovoltaic (PV) Integration Project, which is co-funded by the U.S. Department of Energy (DOE) Office of Energy Efficiency and Renewable Energy (EERE) and the California Solar Initiative (CSI) Research, Development, Demonstration, and Deployment (RD&D) program funded by the California Public Utility Commission (CPUC) and managed by Itron. This project is focused on modeling, quantifying, and mitigating the impacts of large utility-scale PV systems (generally 1-5 MW in size) that are interconnected to the distribution system. This report discusses the concerns utilities have when interconnecting large PV systems that interconnect using PV inverters (a specific application of frequency converters). Additionally, a number of capabilities of PV inverters are described that could be implemented to mitigate the distribution system-level impacts of high-penetration PV integration. Finally, the main issues that need to be addressed to ease the interconnection of large PV systems to the distribution system are presented.

  1. A fault diagnosis system for PV power station based on global partitioned gradually approximation method

    NASA Astrophysics Data System (ADS)

    Wang, S.; Zhang, X. N.; Gao, D. D.; Liu, H. X.; Ye, J.; Li, L. R.

    2016-08-01

    As the solar photovoltaic (PV) power is applied extensively, more attentions are paid to the maintenance and fault diagnosis of PV power plants. Based on analysis of the structure of PV power station, the global partitioned gradually approximation method is proposed as a fault diagnosis algorithm to determine and locate the fault of PV panels. The PV array is divided into 16x16 blocks and numbered. On the basis of modularly processing of the PV array, the current values of each block are analyzed. The mean current value of each block is used for calculating the fault weigh factor. The fault threshold is defined to determine the fault, and the shade is considered to reduce the probability of misjudgments. A fault diagnosis system is designed and implemented with LabVIEW. And it has some functions including the data realtime display, online check, statistics, real-time prediction and fault diagnosis. Through the data from PV plants, the algorithm is verified. The results show that the fault diagnosis results are accurate, and the system works well. The validity and the possibility of the system are verified by the results as well. The developed system will be benefit for the maintenance and management of large scale PV array.

  2. Codes, standards, and PV power systems. A 1996 status report

    SciTech Connect

    Wiles, J

    1996-06-01

    As photovoltaic (PV) electrical power systems gain increasing acceptance for both off-grid and utility-interactive applications, the safety, durability, and performance of these systems gains in importance. Local and state jurisdictions in many areas of the country require that all electrical power systems be installed in compliance with the requirements of the National Electrical Code{reg_sign} (NEC{reg_sign}). Utilities and governmental agencies are now requiring that PV installations and components also meet a number of Institute of Electrical and Electronic Engineers (IEEE) standards. PV installers are working more closely with licensed electricians and electrical contractors who are familiar with existing local codes and installation practices. PV manufacturers, utilities, balance of systems manufacturers, and standards representatives have come together to address safety and code related issues for future PV installations. This paper addresses why compliance with the accepted codes and standards is needed and how it is being achieved.

  3. Fire hazard and other safety concerns of PV systems

    NASA Astrophysics Data System (ADS)

    Dhere, Neelkanth G.

    2011-09-01

    Photovoltaic modules are usually considered safe and reliable. But in case of grid-connected PV systems that are becoming very popular, the issue of fire safety of PV modules is becoming increasingly important due to the employed high voltages of 600 V to 1000 V. The two main factors i.e. open circuiting of the bypass diode and ground fault that are responsible for the fire in the PV systems have been discussed in detail along with numerous real life examples. Recommendations are provided for preventing the fire hazards such as having at least class C fire rated PV modules, proper bypass and blocking diodes and interestingly, having an ungrounded PV system.

  4. Three junction holographic micro-scale PV system

    NASA Astrophysics Data System (ADS)

    Wu, Yuechen; Vorndran, Shelby; Ayala Pelaez, Silvana; Kostuk, Raymond K.

    2016-09-01

    In this work a spectrum splitting micro-scale concentrating PV system is evaluated to increase the conversion efficiency of flat panel PV systems. In this approach, the dispersed spectrum splitting concentration systems is scaled down to a small size and structured in an array. The spectrum splitting configuration allows the use of separate single bandgap PV cells that increase spectral overlap with the incident solar spectrum. This results in an overall increase in the spectral conversion efficiency of the resulting system. In addition other benefits of the micro-scale PV system are retained such reduced PV cell material requirements, more versatile interconnect configurations, and lower heat rejection requirements that can lead to a lower cost system. The system proposed in this work consists of two cascaded off-axis holograms in combination with a micro lens array, and three types of PV cells. An aspherical lens design is made to minimize the dispersion so that higher concentration ratios can be achieved for a three-junction system. An analysis methodology is also developed to determine the optical efficiency of the resulting system, the characteristics of the dispersed spectrum, and the overall system conversion efficiency for a combination of three types of PV cells.

  5. Development of a Dispatchable PV Peak Shainv System. PV: Bonus Program - Phase 1 Report. Volume 1

    SciTech Connect

    1995-10-01

    This report summarizes the work performed by Delmarva Power and Light and its subcontractors in Phase 1 of the US Department of Energy's PV:BONUS Program. The purpose of the program is to develop products and systems for buildings which utilize photovoltaic (N) technology. Beginning with a cooperative research effort with the University of Delaware's Center for Energy and Environmental Policy Research Delmarva Power developed and demonstrated the concept of Dispatchable PV Peak Shaving. This concept and the system which resulted horn the development work are unique from other grid-connected PV systems because it combines a PV, battery energy storage, power conversion and control technologies into an integrated package. Phase 1 began in July 1993 with the installation of a test and demonstration system at Delmarva's Northern Division General Office building near Newark, Delaware. Following initial testing throughout the summer and fall of 1993, significant modifications were made under an amendment to the DOE contract. Work on Phase 1 concluded in the early spring of 1995. Significant progress towards the goal of commercializing the system was made during Phase 1, and is summarized. Based on progress in Phase 1, a proposal to continue the work in Phase 2 was submitted to the US DOE in May 1995. A contract amendment and providing funds for the Phase 2 work is expected in July 1995.

  6. All-AC, building integrated PV system for mass deployment of residential PV systems

    SciTech Connect

    Cammack, Kevin; Augenbraun, Joe; Sun, Dan

    2011-05-17

    Project Objective: Solar Red is developing novel PV installation methods and system designs that lower costs dramatically and allow seamless integration into the structure of any sloped roof using existing construction tools and processes. The overall objective of this project is to address the greatest barriers to massive adoption of residential and small commercial rooftop solar – scalability of installation and total cost of ownership - by moving Solar Red’s snap-in/snap-out PV installation method from the pre-prototype design phase to the development and construction of a deployed prototype system. Financial Summary: Funded through ARRA, DOE and Match Funding Original Project Budget: $229,310 o DOE/ARRA Funding: $150,000 o Match Funding: $79,310 Actual Cost: $216,598 o DOE/ARRA Funding: $150,000 o Match Funding: $120,087 Project Summary: Develop snap-in/snap-out mounting system for low-cost, thin-film solar panels – Lower installation cost – Lower sales costs – Lower training/expertise barriers

  7. Performance and Degradation Analysis of Operating PV Systems

    NASA Astrophysics Data System (ADS)

    Da Silva Freire, Felipe

    The environmental concerns together with the decrease in technology cost lead the solar market to growth rapidly along the last decade. The photovoltaic (PV) systems are one of the solar energy alternatives and the silicon solar cells are currently the most widespread technology. Photovoltaic (PV) modules are considered the most reliable component of a photovoltaic system. The reliability and lifetime depends on the modules energy conversion performance and degradation modes. The analysis of monitoring data give insights about the PV system performance along its service time. The comparison between this data and mathematical models configure a way to predict the futures and new PV installations performance. The goal of this study is to understand the PV systems performance and degradation along its lifetime. A mathematical model was employed to predict the power output of a real, relatively new operating PV system with respect to environmental parameters temperature, irradiance and cloud coverage. The model used is based on one diode ideality factor and takes into account the parasitic series resistance. The results have been compared with the actual PV output data collected for the year 2014 and show good correlation. As the model predicts the system power output assuming the system in new conditions, the deviation in performance of the real data in comparison to the modeling results need to be further investigated for systems in service for longer time. For this propose, the study presents a condensed review of various causes of degradation in silicon PV modules and techniques to observe and investigate these degradation mechanisms. Major effects on output performance exhibit increase in observed ideality factor n2 and recombination current J02 primarily caused by decrease in minority carrier lifetime, shunts and increase in series resistance. The study further, investigates the governing degradation modes on a ten years old PV crystalline silicon module

  8. Instrumentation for Evaluating PV System Performance Losses from Snow

    SciTech Connect

    Marion, B.; Rodriguez, J.; Pruett, J.

    2009-01-01

    When designing a photovoltaic (PV) system for northern climates, the prospective installation should be evaluated with respect to the potentially detrimental effects of snow preventing solar radiation from reaching the PV cells. The extent to which snow impacts performance is difficult to determine because snow events also increase the uncertainty of the solar radiation measurement, and the presence of snow needs to be distinguished from other events that can affect performance. This paper describes two instruments useful for evaluating PV system performance losses from the presence of snow: (1) a pyranometer with a heater to prevent buildup of ice and snow, and (2) a digital camera for remote retrieval of images to determine the presence of snow on the PV array.

  9. Control Strategies for the DAB Based PV Interface System.

    PubMed

    El-Helw, Hadi M; Al-Hasheem, Mohamed; Marei, Mostafa I

    2016-01-01

    This paper presents an interface system based on the Dual Active Bridge (DAB) converter for Photovoltaic (PV) arrays. Two control strategies are proposed for the DAB converter to harvest the maximum power from the PV array. The first strategy is based on a simple PI controller to regulate the terminal PV voltage through the phase shift angle of the DAB converter. The Perturb and Observe (P&O) Maximum Power Point Tracking (MPPT) technique is utilized to set the reference of the PV terminal voltage. The second strategy presented in this paper employs the Artificial Neural Network (ANN) to directly set the phase shift angle of the DAB converter that results in harvesting maximum power. This feed-forward strategy overcomes the stability issues of the feedback strategy. The proposed PV interface systems are modeled and simulated using MATLAB/SIMULINK and the EMTDC/PSCAD software packages. The simulation results reveal accurate and fast response of the proposed systems. The dynamic performance of the proposed feed-forward strategy outdoes that of the feedback strategy in terms of accuracy and response time. Moreover, an experimental prototype is built to test and validate the proposed PV interface system.

  10. Control Strategies for the DAB Based PV Interface System

    PubMed Central

    El-Helw, Hadi M.; Al-Hasheem, Mohamed; Marei, Mostafa I.

    2016-01-01

    This paper presents an interface system based on the Dual Active Bridge (DAB) converter for Photovoltaic (PV) arrays. Two control strategies are proposed for the DAB converter to harvest the maximum power from the PV array. The first strategy is based on a simple PI controller to regulate the terminal PV voltage through the phase shift angle of the DAB converter. The Perturb and Observe (P&O) Maximum Power Point Tracking (MPPT) technique is utilized to set the reference of the PV terminal voltage. The second strategy presented in this paper employs the Artificial Neural Network (ANN) to directly set the phase shift angle of the DAB converter that results in harvesting maximum power. This feed-forward strategy overcomes the stability issues of the feedback strategy. The proposed PV interface systems are modeled and simulated using MATLAB/SIMULINK and the EMTDC/PSCAD software packages. The simulation results reveal accurate and fast response of the proposed systems. The dynamic performance of the proposed feed-forward strategy outdoes that of the feedback strategy in terms of accuracy and response time. Moreover, an experimental prototype is built to test and validate the proposed PV interface system. PMID:27560138

  11. Plug and Play PV Systems for American Homes

    SciTech Connect

    Hoepfner, Christian

    2016-12-22

    The core objectives of the Plug & Play PV Systems Project were to develop a PV system that can be installed on a residential rooftop for less than $1.50/W in 2020, and in less than 10 hours (from point of purchase to commissioning). The Fraunhofer CSE team’s approach to this challenge involved a holistic approach to system design – hardware and software – that make Plug & Play PV systems: • Quick, easy, and safe to install • Easy to demonstrate as code compliant • Permitted, inspected, and interconnected via an electronic process Throughout the three years of work during this Department of Energy SunShot funded project, the team engaged in a substantive way with inspectional services departments and utilities, manufacturers, installers, and distributors. We received iterative feedback on the system design and on ideas for how such systems can be commercialized. This ultimately led us to conceiving of Plug & Play PV Systems as a framework, with a variety of components compatible with the Plug & Play PV approach, including string or microinverters, conventional modules or emerging lightweight modules. The framework enables a broad group of manufacturers to participate in taking Plug & Play PV Systems to market, and increases the market size for such systems. Key aspects of the development effort centered on the system hardware and associated engineering work, the development of a Plug & Play PV Server to enable the electronic permitting, inspection and interconnection process, understanding the details of code compliance and, on occasion, supporting applications for modifications to the code to allow lightweight modules, for example. We have published a number of papers on our testing and assessment of novel technologies (e.g., adhered lightweight modules) and on the electronic architecture.

  12. Analysis on Possible Introduction of PV System Considering Output Power Fluctuation and Battery Technology Employing Optimal Power Generation Mix Model

    NASA Astrophysics Data System (ADS)

    Komiyama, Ryoichi; Shibata, Saeko; Nakamura, Yosuke; Fujii, Yasumasa

    This paper presents the evaluation on the impact of an extensive introduction of photovoltaic (PV) system and stationary battery technology into optimal power generation mix in Kanto and Kinki region. The introduction of solar PV system is expected to be extensively deployed in Japanese household sector and utility company in order to address the concerns of energy security and climate change. Considering this expected large-scale deployment of PV system in electric power system, it is necessary to investigate the optimal power generation mix which is technologically capable of controlling and accommodating the intermittent output-power fluctuation inherently derived from PV system. On these backgrounds, we develop both solar photovoltaic power generation model and optimal power generation mix model, including stationary battery technology, which are able to explicitly analyze the impact of PV output fluctuation in detailed resolution of time interval like 10 minutes at consecutive 365 days. Simulation results reveal that PV introduction does not necessarily increase battery technology due to the cost competitiveness of thermal power plants in load following requirement caused by PV system. Additionally, on the basis of sensitivity analysis on PV system cost, dramatic cost reduction proves to be indispensable enough for PV to supply a bulk of electricity similarly as thermal and nuclear power plant.

  13. Solar Photovoltaic (PV) Distributed Generation Systems - Control and Protection

    NASA Astrophysics Data System (ADS)

    Yi, Zhehan

    This dissertation proposes a comprehensive control, power management, and fault detection strategy for solar photovoltaic (PV) distribution generations. Battery storages are typically employed in PV systems to mitigate the power fluctuation caused by unstable solar irradiance. With AC and DC loads, a PV-battery system can be treated as a hybrid microgrid which contains both DC and AC power resources and buses. In this thesis, a control power and management system (CAPMS) for PV-battery hybrid microgrid is proposed, which provides 1) the DC and AC bus voltage and AC frequency regulating scheme and controllers designed to track set points; 2) a power flow management strategy in the hybrid microgrid to achieve system generation and demand balance in both grid-connected and islanded modes; 3) smooth transition control during grid reconnection by frequency and phase synchronization control between the main grid and microgrid. Due to the increasing demands for PV power, scales of PV systems are getting larger and fault detection in PV arrays becomes challenging. High-impedance faults, low-mismatch faults, and faults occurred in low irradiance conditions tend to be hidden due to low fault currents, particularly, when a PV maximum power point tracking (MPPT) algorithm is in-service. If remain undetected, these faults can considerably lower the output energy of solar systems, damage the panels, and potentially cause fire hazards. In this dissertation, fault detection challenges in PV arrays are analyzed in depth, considering the crossing relations among the characteristics of PV, interactions with MPPT algorithms, and the nature of solar irradiance. Two fault detection schemes are then designed as attempts to address these technical issues, which detect faults inside PV arrays accurately even under challenging circumstances, e.g., faults in low irradiance conditions or high-impedance faults. Taking advantage of multi-resolution signal decomposition (MSD), a powerful signal

  14. Economic analysis of PV hybrid power system: Pinnacles National Monument

    SciTech Connect

    Rosenthal, A.; Durand, S.; Thomas, M.; Post, H.

    1997-11-01

    PV hybrid electric power systems can offer an economically competitive alternative to engine generator (genset) systems in many off-grid applications. Besides the obvious `green` advantages of producing less noise and emissions, the PV hybrid can, in some cases, offer a lower life-cycle cost (LCC) then the genset. This paper evaluates the LCC of the 9.6 kWp PV hybrid power system installed by the National Park Services (NPS) at Pinnacles National Monument, CA. NPS motivation for installation of this hybrid was not based on economics, but rather the need to replace two aging diesel gensets with an alternative that would be quieter, fuel efficient, and more in keeping with new NPS emphasis on sustainable design and operations. In fact, economic analysis shows a lower 20-year LCC for the installed PV hybrid than for simple replacement of the two gensets. The analysis projects are net savings by the PV hybrid system of $83,561 and over 162,000 gallons of propane when compared with the genset-only system. This net savings is independent of the costs associated with environmental emissions. The effects of including emissions costs, according to NPS guidelines, is also discussed. 5 refs., 2 figs., 3 tabs.

  15. Recent advances in PV systems technology development in Europe

    SciTech Connect

    Imamura, M.; Grottke, M.; Weiss, I.

    1995-11-01

    The objectives of the photovoltaics (PV) systems technology development were to study several aspects of plant design, monitoring, control, operation, and management of different types of photovoltaic plants. Unsolved problems were to be identified and analysed, and guidelines to improve the monitoring system were to be developed. Principal studies are summarized.

  16. 3-Port Single-Stage PV & Battery Converter Improves Efficiency and Cost in Combined PV/Battery Systems

    SciTech Connect

    Bundschuh, Paul

    2013-03-23

    Due to impressive cost reductions in recent years, photovoltaic (PV) generation is now able to produce electricity at highly competitive prices, but PV’s inherent intermittency reduces the potential value of this energy. The integration of battery storage with PV will be transformational by increasing the value of solar. Utility scale systems will benefit by firming intermittency including PV ramp smoothing, grid support and load shifting, allowing PV to compete directly with conventional generation. For distributed grid-tied PV adding storage will reduce peak demand utility charges, as well as providing backup power during power grid failures. The largest long term impact of combined PV and battery systems may be for delivering reliable off-grid power to the billions of individuals globally without access to conventional power grids, or for billions more that suffer from daily power outages. PV module costs no longer dominate installed PV system costs. Balance-of-System (BOS) costs including the PV inverter and installation now contribute the majority of installed system costs. Battery costs are also dropping faster than installation and battery power converter systems. In each of these separate systems power converters have become a bottleneck for efficiency, cost and reliability. These bottlenecks are compounded in hybrid power conversion systems that combine separate PV and battery converters. Hybrid power conversion systems have required multiple power converters hardware units and multiple power conversion steps adding to efficiency losses, product and installation costs, and reliability issues. Ideal Power Converters has developed and patented a completely new theory of operation for electronic power converters using its indirect EnergyPacket Switching™ topology. It has established successful power converter products for both PV and battery systems, and its 3-Port Hybrid Converter is the first product to exploit the topology’s capability for the

  17. High-Penetration PV Deployment in the Arizona Public Service System, Phase 1 Update: Preprint

    SciTech Connect

    Hambrick, J.; Narang, D.

    2012-06-01

    In an effort to better understand the impacts of high penetrations of photovoltaic generators on distribution systems, Arizona Public Service and its partners have begun work on a multi-year project to develop the tools and knowledge base needed to safely and reliably integrate high penetrations of utility- and residential-scale photovoltaics (PV). Building upon the APS Community Power Project -- Flagstaff Pilot, this project will analyze the impact of PV on a representative feeder in northeast Flagstaff. To quantify and catalog the effects of the estimated 1.3 MW of PV that will be installed on the feeder (both smaller units at homes as well as large, centrally located systems), high-speed weather and electrical data acquisition systems and digital 'smart' meters are being designed and installed to facilitate monitoring and to build and validate comprehensive, high-resolution models of the distribution system. These models will be used to analyze the impacts of the PV on distribution circuit protection systems (including anti-islanding), predict voltage regulation and phase balance issues, and develop volt/var control schemes. This paper continues from a paper presented at the 2011 IEEE PVSC conference that introduces the project and describes some of the preliminary consideration, as well as project plans and early results. This paper gives a status update of the project and presents selected results from Phase 2 of the project. It discusses baseline feeder modeling, load allocation, data acquisition, utility-scale PV integration, preliminary model validation, and plans for future phases.

  18. Berkeley Program Offers New Option for Financing Residential PV Systems

    SciTech Connect

    Bolinger, Mark A

    2008-07-06

    Readily accessible credit has often been cited as a necessary ingredient to open up the market for residential photovoltaic (PV) systems. Though financing does not reduce the high up-front cost of PV, by spreading that cost over some portion of the system's life, financing can certainly make PV systems more affordable. As a result, a number of states have, in the past, set up special residential loan programs targeting the installation of renewable energy systems and/or energy-efficiency improvements and often featuring low interest rates, longer terms and no-hassle application requirements. Historically, these loan programs have had mixed success (particularly for PV), for a variety of reasons, including a historical lack of homeowner interest in PV, a lack of program awareness, a reduced appeal in a low-interest-rate environment, and a tendency for early PV adopters to be wealthy and not in need of financing. Some of these barriers have begun to fade. Most notably, homeowner interest in PV has grown in some states, particularly those that offer solar rebates. The passage of the Energy Policy Act of 2005 (EPAct 2005), however, introduced one additional roadblock to the success of low-interest PV loan programs: a residential solar investment tax credit (ITC), subject to the Federal government's 'anti-double-dipping' rules. Specifically, the residential solar ITC--equal to 30% of the system's tax basis, capped at $2000--will be reduced or offset if the system also benefits from what is known as 'subsidized energy financing', which is likely to include most government-sponsored low-interest loan programs. Within this context, it has been interesting to note the recent flurry of announcements from a number of U.S cities concerning a new type of PV financing program. Led by the city of Berkeley, Calif., these cities propose to offer their residents the ability to finance the installation of a PV system using increased property tax assessments, rather than a more

  19. Performance and economics of the PV hybrid power system at Dangling Rope Marina, Utah

    NASA Astrophysics Data System (ADS)

    Rosenthal, Andrew L.

    1999-03-01

    The National Park Service has operated a large photovoltaic (PV) hybrid power system at the Dangling Rope Marina since August 1996. Performance and economic analyses for this system based on its first year of operation have been published elsewhere [1,2]. Now, as the system enters its third year of operation, recent changes to the site electrical load and impending additions to the PV array raise new interest in this site as the subject of analysis and evaluation. In 1998, energy conservation measures reduced the site electrical load by 10-12%. At the same time, funding has been allocated to expand the PV array by 40% in 1999. This paper analyzes the effects that these changes will have on the site's fuel use and 20-year life cycle cost.

  20. Performance and economics of the PV hybrid power system at Dangling Rope Marina, Utah

    SciTech Connect

    Rosenthal, A.L.

    1999-03-01

    The National Park Service has operated a large photovoltaic (PV) hybrid power system at the Dangling Rope Marina since August 1996. Performance and economic analyses for this system based on its first year of operation have been published elsewhere [1,2]. Now, as the system enters its third year of operation, recent changes to the site electrical load and impending additions to the PV array raise new interest in this site as the subject of analysis and evaluation. In 1998, energy conservation measures reduced the site electrical load by 10{endash}12{percent}. At the same time, funding has been allocated to expand the PV array by 40{percent} in 1999. This paper analyzes the effects that these changes will have on the site{close_quote}s fuel use and 20-year life cycle cost. {copyright} {ital 1999 American Institute of Physics.}

  1. Development of standardized, low-cost AC PV systems. Phase I annual report, 7 September 1995--7 November 1996

    SciTech Connect

    Strong, S.J.; Wohlgemuth, J.H.; Kaelin, M.

    1997-06-01

    The objectives of this two-year program are to improve the reliability and safety and reduce the cost of installed grid-connected PV systems by creating standardized, pre-engineered components and an enhanced, low-cost, 250-Watt micro inverter. These advances will be combined with the new, large area Solarex MSX-240 PV module resulting in standard, modular AC PV {open_quotes}building blocks{close_quotes} used to create utility-interactive PV systems as small as one module to many thousands of modules to suit virtually any application. AC PV building blocks will be developed to meet the requirements of the U.S., Japanese and European markets.

  2. Cost of energy from utility-scale PV systems

    SciTech Connect

    Stolte, W.J.; Whisnant, R.A.; McGowin, C.R.

    1994-12-31

    The cost of energy produced by three different photovoltaic (PV) power plants was estimated based on PV cell and module technology expected to be available by 1995. Plant designs were created for two high concentration PV plants (500 suns), both based on advanced back-contact silicon cell technology, and a thin-film, flat plate plant using copper indium diselenide (CIS) cell technology. The concentrator plants included a central receiver plant using stretched-membrane heliostats and a Fresnel-lens module plant, both utilizing two-axis tracking. Basic plant design factors were selected to minimize 30-year levelized energy costs. Total capital requirements to construct the three plants were estimated through detailed cost estimates. Costs of the cell and module components of the plants were determined by modeling their manufacturing processes when producing modules at an annual rate of both 25 MW/year and 100 MW/year. Energy outputs were determined by computer modeling with hourly insolation and temperature profiles for the two sites. Power system simulation studies were carried out to estimate the impact of the PV plants on system power production cost using synthetic, but realistic, utility system definitions. Both high and low growth rate utility system expansion plans were considered, and capacity and energy credits were calculated. Additionally, credits were calculated for environmental externalities. Benefit/cost ratios for each plant and site were determined. The results of the study provide projections in 1990 dollars of the cost of electric energy from utility-scale PV plants assuming a mature technology that may be available by about 1995. The cost of energy produced by the CIS flat plate plant was projected to be as low as 10.8 cents/kWh. The concentrator plant results were only slightly higher at 12.3 cents/kWh for the Fresnel lens plant and 13.1 cents/kWh for the central receiver plant. 18 refs., 11 figs., 7 tabs.

  3. Comparative Study Between Wind and Photovoltaic (PV) Systems

    NASA Astrophysics Data System (ADS)

    Taha, Wesam

    This paper reviews two renewable energy systems; wind and photovoltaic (PV) systems. The common debate between the two of them is to conclude which one is better, in terms of cost and efficiency. Therefore, comparative study, in terms of cost and efficiency, is attempted. Regarding total cost of both, wind and PV systems, many parameters must be taken into consideration such as availability of energy (either wind or solar), operation and maintenance, availability of costumers, political influence, and the components used in building the system. The main components and parameters that play major role in determining the overall efficiency of wind systems are the wind turbine generator (WTG), gearbox and control technologies such as power, and speed control. On the other hand, in grid-connected PV systems (GCPVS), converter architecture along with maximum power point tracking (MPPT) algorithm and inverter topologies are the issues that affects the efficiency significantly. Cost and efficiency analyses of both systems have been carried out based on the statistics available till today and would be useful in the progress of renewable energy penetration throughout the world.

  4. Distributed Solar PV for Electricity System Resiliency: Policy and Regulatory Considerations (Brochure)

    SciTech Connect

    Not Available

    2014-11-01

    Distributed Solar PV systems have the potential of increasing the grid's resiliency to unforeseen events, such as extreme weather events and attacks. This paper presents the role that distributed PV can play in electric grid resiliency, introduces basic system design requirements and options, and discusses the regulatory and policy options for supporting the use of distributed PV for the purpose of increased electricity resiliency.

  5. Best practices for PV solar home system projects

    SciTech Connect

    Cosgrove-Davies, M.; Cabraal, A.

    1994-12-31

    PV solar home systems (SHS) are increasingly employed as an energy supply option for rural populations. The past 20 years` experience with small-scale SHS programs in developing countries has had mixed results. However, efforts in recent years have been more successful. In support of World Bank lending operations, the Banks Asia Alternative Energy Unit (ASTAE) has undertaken a series of case studies of currently operating SHS programs in Indonesia, Sri Lanka, the Philippines, and the Dominican Republic. These programs have varying degrees of government, NGO, and private sector involvement. This paper summarizes ASTAE`s draft Solar Photovoltaics: Best Practices for Household Electrification report which identifies the institutional, financial, and technical factors fundamental to the success of a PV solar home system project. The final version of the ASTAE report will incorporate comments from an international group of peer reviewers.

  6. Multi-Objective Advanced Inverter Controls to Dispatch the Real and Reactive Power of Many Distributed PV Systems.

    SciTech Connect

    Reno, Matthew J.; Lave, Matthew Samuel; Broderick, Robert Joseph; Seuss, John; Grijalva, Santiago

    2016-01-01

    The research presented in this report compares several real - time control strategies for the power output of a large number of PV distributed throughout a large distribution feeder circuit. Both real and reactive power controls are considered with the goal of minimizing network over - voltage violations caused by large amounts of PV generation. Several control strategies are considered under various assumptions regarding the existence and latency of a communication network. The control parameters are adjusted to maximize the effectiveness of each control. The controls are then compared based on their ability to achieve multiple objectiv es. These objectives include minimizing the total number of voltage violations , minimizing the total amount of PV energy curtailed or reactive power generated, and maximizing the fairness of any control action among all PV systems . The controls are simulat ed on the OpenDSS platform using time series load and spatially - distributed irradiance data.

  7. Distributed Power Electronics for PV Systems (Presentation)

    SciTech Connect

    Deline, C.

    2011-12-01

    An overview of the benefits and applications of microinverters and DC power optimizers in residential systems. Some conclusions from this report are: (1) The impact of shade is greater than just the area of shade; (2) Additional mismatch losses include panel orientation, panel distribution, inverter voltage window, soiling; (3) Per-module devices can help increase performance, 4-12% or more depending on the system; (4) Value-added benefits (safety, monitoring, reduced design constraints) are helping their adoption; and (5) The residential market is growing rapidly. Efficiency increases, cost reductions are improving market acceptance. Panel integration will further reduce price and installation cost. Reliability remains an unknown.

  8. PV Charging System for Remote Area Operations

    SciTech Connect

    Ilsemann, Frederick; Thompson, Roger

    2008-07-31

    The objective of this project is to provide the public with a study of new as well existing technology to recharge batteries used in the field. A new product(s) will also be built based upon the information ascertained. American Electric Vehicles, Inc. (AEV) developed systems and methods suitable for charging state-of-the-art lithium-ion batteries in remote locations under both ideal and cloudy weather conditions. Conceptual designs are described for existing and next generation technology, particularly as regards solar cells, peak power trackers and batteries. Prototype system tests are reported.

  9. Analysis of Dissemination of Residential PV Systems in Japan

    NASA Astrophysics Data System (ADS)

    Endo, Eiichi

    This paper focuses on residential PV systems in Japan. It projects installation and installed capacity of residential PV systems by analyzing correlation between their pay-back period and annual installation by new and existing houses. Exponential and hyperbolic curves are applied for correlation analysis. But exponential curve shows better fit than hyperbolic one. PV installation in new houses shows stronger correlation with pay-back period than that in existing houses. For the installation projection, target and delayed scenarios are assumed. In the target scenario, target price is achieved as planned. However it is achieved with delay in the delayed scenario. Ongoing subsidy and feed-in-tariff is also assumed. Based on the results of the analysis, the target cumulative installation and installed capacity are achieved in the target scenario. They are not so affected even if without subsidy and feed-in-tariff. But they become almost half in the delayed scenario compared with that in the target scenario. This means system price reduction by R&D and mass production is more effective than ongoing dissemination acceleration programs. To achieve the target capacity, not only cost reduction, but also conversion efficiency improvement by R&D is indispensable.

  10. How PV system ownership can impact the market value of residential homes

    SciTech Connect

    Klise, Geoffrey Taylor; Johnson, Jamie L.

    2014-01-01

    There are multiple ways for a homeowner to obtain the electricity generating and savings benefits offered by a photovoltaic (PV) system. These include purchasing a PV system through various financing mechanisms, or by leasing the PV system from a third party with multiple options that may include purchase, lease renewal or PV system removal. The different ownership options available to homeowners presents a challenge to appraisal and real estate professionals during a home sale or refinance in terms of how to develop a value that is reflective of the PV systems operational characteristics, local market conditions, and lender and underwriter requirements. This paper presents these many PV system ownership options with a discussion of what considerations an appraiser must make when developing the contributory value of a PV system to a residential property.

  11. A MPPT Algorithm Based PV System Connected to Single Phase Voltage Controlled Grid

    NASA Astrophysics Data System (ADS)

    Sreekanth, G.; Narender Reddy, N.; Durga Prasad, A.; Nagendrababu, V.

    2012-10-01

    Future ancillary services provided by photovoltaic (PV) systems could facilitate their penetration in power systems. In addition, low-power PV systems can be designed to improve the power quality. This paper presents a single-phase PV systemthat provides grid voltage support and compensation of harmonic distortion at the point of common coupling thanks to a repetitive controller. The power provided by the PV panels is controlled by a Maximum Power Point Tracking algorithm based on the incremental conductance method specifically modified to control the phase of the PV inverter voltage. Simulation and experimental results validate the presented solution.

  12. A New Approach to Design of an optimized Grid Tied Smart Solar Photovoltaic (PV) System

    NASA Astrophysics Data System (ADS)

    Farhad, M. Mehedi; Ali, M. Mohammad; Iqbal, M. Asif; Islam, N. Nahar; Ashraf, N.

    2012-11-01

    Energy is the key element for the economical development of a country. With the increasing concern about the global demand for Renewable Energy (RE) energy, it is very much important to reduce the cost of the whole solar photovoltaic (PV) system. Still now most of the solar photovoltaic (PV) system is highly expensive. In this paper we have shown that grid tied solar system can be developed by omitting the energy storage device like large capacity battery bank. It will not only reduce the internallosses for charging and discharging of battery bank but also at the same time a large amount of cost of the battery will be reduced. So, the system maintenance cost will be reduced also. We have proposed a new approach to design a photovoltaic (PV) solar power system which can be operated by feeding the solar power to the national grid along with the residential load. Again if there is an extra power demand for residential load along with the solar power then this system can also provide an opportunity to consume the power from the national grid. The total system is controlled with the help of some the sensors and a microcontroller. As a whole a significant reduction in the system costs and efficient system performance can be realized.

  13. Rooftop PV system. Final technical progress report, Phase II

    SciTech Connect

    1995-08-01

    Under this four-year PV:BONUS Program, ECD and United Solar are developing and demonstrating two new lightweight flexible building integrated Photovoltaic (BIPV) modules specifically designed as exact replacements for conventional asphalt shingles and standing seam metal roofing. These modules can be economically and aesthetically integrated into new residential and commercial buildings, and address the even larger roofing replacement market. The modules are designed to be installed by roofing contractors without special training which minimizes the installation and balance of system costs. The modules will be fabricated from high-efficiency, multiple-junction a-Si alloy solar cells developed by ECD and United Solar. Under the Phase I Program, which ended in March 1994, we developed two different concept designs for rooftop PV modules: (1) the United Solar overlapping (asphalt shingle replacement) shingle-type modules and (2) the ECD metal roof-type modules. We also developed a plan for fabricating, testing and demonstrating these modules. Candidate demonstration sites for our rooftop PV modules were identified and preliminary engineering designs for these demonstrations were developed; a marketing study plan was also developed. The major objectives of the Phase II Program, which started in June 1994 was (1) to develop, test, and qualify these new rooftop modules; (2) to develop mechanical and electrical engineering specifications for the demonstration projects; and (3) to develop a marketing/commercialization plan.

  14. Solar PV Manufacturing Cost Model Group: Installed Solar PV System Prices (Presentation)

    SciTech Connect

    Goodrich, A. C.; Woodhouse, M.; James, T.

    2011-02-01

    EERE's Solar Energy Technologies Program is charged with leading the Secretary's SunShot Initiative to reduce the cost of electricity from solar by 75% to be cost competitive with conventional energy sources without subsidy by the end of the decade. As part of this Initiative, the program has funded the National Renewable Energy Laboratory (NREL) to develop module manufacturing and solar PV system installation cost models to ensure that the program's cost reduction targets are carefully aligned with current and near term industry costs. The NREL cost analysis team has leveraged the laboratories' extensive experience in the areas of project finance and deployment, as well as industry partnerships, to develop cost models that mirror the project cost analysis tools used by project managers at leading U.S. installers. The cost models are constructed through a "bottoms-up" assessment of each major cost element, beginning with the system's bill of materials, labor requirements (type and hours) by component, site-specific charges, and soft costs. In addition to the relevant engineering, procurement, and construction costs, the models also consider all relevant costs to an installer, including labor burdens and overhead rates, supply chain costs, and overhead and materials inventory costs, and assume market-specific profits.

  15. Rooftop PV system. PV:BONUS Phase 3B, final technical report

    SciTech Connect

    1998-11-01

    Under the PV:BONUS Program, ECD and United Solar developed, demonstrated and commercialized two new lightweight, flexible BIPV modules specifically designed as replacements for conventional asphalt shingles and standing seam metal roofing. These modules can be economically and aesthetically integrated into new residential and commercial buildings, and can be used to address the even larger roofing-replacement market. An important design feature of these modules, which minimizes the installation and balance-of-system costs, is their ability to be installed by conventional roofing contractors without special training. The modules are fabricated from high-efficiency, triple-junction spectrum-splitting a-Si alloy solar cells developed by ECD and United Solar. These cells are produced on thin, flexible stainless steel substrates and encapsulated with polymer materials. The Phase 3 program began in August 1995. The principal tasks and goals of this program, which have all been successfully completed by ECD and United Solar, are described in the body and appendices of this report.

  16. Theoretical analysis and experimental study on the PV-IESAHP system

    NASA Astrophysics Data System (ADS)

    Wu, Xingying

    2017-05-01

    Solar photovoltaic/thermal integration (PV/T) and heat pump are very important techniques for energy conservation and carbon reduction. A practical design for an integrated PV/T and heat pump system is presented, the integrated system is called the Photovoltaic-Indirect Expansion Solar Assisted Heat Pump (PV-IESAHP) system, which uses the heat energy supplied by PV/T as an evaporating heat source and can achieve high coefficient of performance(COP). It is essential to master the completed design idea and thermodynamic analysis method for the integration of PV/T and heat pump. In this study a kind of theoretical and matching performance model of the PV-IESAHP system is established, and a series of experiments were conducted to study the performance of the heat-pipe type PV/T experimental system and heat hump experimental system. Moreover, energy and energy analyses were used to investigate the performance of the systems. The results show that the COP of the PV-IESAHP system is about 4.0, and the energy efficiency about 0.05, which not only implies that the PV-IESAHP system has a significant energy-saving potential, but also will provide a theoretical basis for the application and parameters design of the PV-IESAHP system in the future.

  17. Assuring long-term reliability of concentrator PV systems

    NASA Astrophysics Data System (ADS)

    McConnell, R.; Garboushian, V.; Brown, J.; Crawford, C.; Darban, K.; Dutra, D.; Geer, S.; Ghassemian, V.; Gordon, R.; Kinsey, G.; Stone, K.; Turner, G.

    2009-08-01

    Concentrator PV (CPV) systems have attracted significant interest because these systems incorporate the world's highest efficiency solar cells and they are targeting the lowest cost production of solar electricity for the world's utility markets. Because these systems are just entering solar markets, manufacturers and customers need to assure their reliability for many years of operation. There are three general approaches for assuring CPV reliability: 1) field testing and development over many years leading to improved product designs, 2) testing to internationally accepted qualification standards (especially for new products) and 3) extended reliability tests to identify critical weaknesses in a new component or design. Amonix has been a pioneer in all three of these approaches. Amonix has an internal library of field failure data spanning over 15 years that serves as the basis for its seven generations of CPV systems. An Amonix product served as the test CPV module for the development of the world's first qualification standard completed in March 2001. Amonix staff has served on international standards development committees, such as the International Electrotechnical Commission (IEC), in support of developing CPV standards needed in today's rapidly expanding solar markets. Recently Amonix employed extended reliability test procedures to assure reliability of multijunction solar cell operation in its seventh generation high concentration PV system. This paper will discuss how these three approaches have all contributed to assuring reliability of the Amonix systems.

  18. Quantify Degradation Rates and Mechanisms of PV Modules and Systems Installed in Florida Through Comprehensive Experimental and Theoretical Analysis (Poster)

    SciTech Connect

    Sorloaica-Hickman, N.; Davis, K.; Kurtz, S.; Jordan, D.

    2011-02-01

    The economic viability of photovoltaic (PV) technologies is inextricably tied to both the electrical performance and degradation rate of the PV systems, which are the generators of electrical power in PV systems. Over the past 15 years, performance data have been collected on numerous PV systems installed throughout the state of Florida and will be presented.

  19. The impact of codes and standards on PV systems

    SciTech Connect

    Wiles, J.C.

    1996-11-01

    Terrestrial photovoltaic (PV) power systems, as field-installed and wired electrical power systems, may be subject to codes such as the National Electrical Code{reg_sign} (NEC{reg_sign}) and standards established by the Institute of Electrical and Electronic Engineers (IEEE) and Underwriters Laboratories (UL{reg_sign}). Codes and standards may be required, not only by the local jurisdiction where the system is installed, but also by the purchasing agency. While the application and enforcement of the applicable codes and standards may enhance safety, it may also affect performance and increase system costs. Although there is an increase in the number of components and systems that meet standards and codes, systems are still being installed with components that do not comply with any standards, while using installation methods that do not comply with the required codes. Performance and cost may be impacted by code compliance, but safety and product liability will dictate the final approach.

  20. Enhancement of real-time EPICS IOC PV management for the data archiving system

    NASA Astrophysics Data System (ADS)

    Kim, Jae-Ha

    2015-10-01

    The operation of a 100-MeV linear proton accelerator, the major driving values and experimental data need to be archived. According to the experimental conditions, different data are required. Functions that can add new data and delete data in real time need to be implemented. In an experimental physics and industrial control system (EPICS) input output controller (IOC), the value of process variables (PVs) are matched with the driving values and data. The PV values are archived in text file format by using the channel archiver. There is no need to create a database (DB) server, just a need for large hard disk. Through the web, the archived data can be loaded, and new PV values can be archived without stopping the archive engine. The details of the implementation of a data archiving system with channel archiver are presented, and some preliminary results are reported.

  1. Design and Implementation of an Innovative Residential PV System

    NASA Astrophysics Data System (ADS)

    Najm, Elie Michel

    This work focuses on the design and implementation of an innovative residential PV system. In chapter one, after an introduction related to the rapid growth of solar systems' installations, the most commonly used state of the art solar power electronics' configurations are discussed, which leads to introducing the proposed DC/DC parallel configuration. The advantages and disadvantages of each of the power electronics' configurations are deliberated. The scope of work in the power electronics is defined in this chapter to be related to the panel side DC/DC converter. System integration and mechanical proposals are also within the scope of work and are discussed in later chapters. Operation principle of a novel low cost PV converter is proposed in chapter 2. The proposal is based on an innovative, simplified analog implementation of a master/slave methodology resulting in an efficient, soft-switched interleaved variable frequency flybacks, operating in the boundary conduction mode (BCM). The scheme concept and circuit configuration, operation principle and theoretical waveforms, design equations, and design considerations are presented. Furthermore, design examples are also given, illustrating the significance of the newly derived frequency equation for flybacks operating in BCM. In chapters 3, 4, and 5, the design implementation and optimization of the novel DC/DC converter illustrated in chapter 2 are discussed. In chapter 3, a detailed variable frequency BCM flyback design model leading to optimizing the component selections and transformer design, detailed in chapter 4, is presented. Furthermore, in chapter 4, the method enabling the use of lower voltage rating switching devices is also discussed. In chapter 5, circuitry related to Start-UP, drive for the main switching devices, zero-voltage-switching (ZVS) as well as turn OFF soft switching and interleaving control are fully detailed. The experimental results of the proposed DC/DC converter are presented in

  2. Intelligent control of PV system on the basis of the fuzzy recurrent neuronet*

    NASA Astrophysics Data System (ADS)

    Engel, E. A.; Kovalev, I. V.; Engel, N. E.

    2016-04-01

    This paper presents the fuzzy recurrent neuronet for PV system’s control. Based on the PV system’s state, the fuzzy recurrent neural net tracks the maximum power point under random perturbations. The validity and advantages of the proposed intelligent control of PV system are demonstrated by numerical simulations. The simulation results show that the proposed intelligent control of PV system achieves real-time control speed and competitive performance, as compared to a classical control scheme on the basis of the perturbation & observation algorithm.

  3. Field Demonstration of Using Advanced PV Inverter Functionality to Mitigate the Impacts of High-Penetration PV Grid Integration on the Distribution System

    SciTech Connect

    Mather, Barry; Gebeyehu, Araya

    2015-06-14

    This paper describes a field demonstration that was completed to show the ability of currently installed PV inverters to implement advanced PV inverter functionality and that such functionality was effective at reducing the voltage-related PV impacts of high-penetration PV integration. A distribution circuit was instrumented and then tested for a two week period using off-unity power factor operation. Specifically, an inductive power factor of -0.95 was demonstrated. The results show that the PV inverters were capable of such operation and that the use of off-unity power factor operation was highly effective at reducing the voltage-related impacts of the PV systems interconnected to the circuits used in the demonstration. The impacts of using off-unity power factor operation - resulting in additional reactive current flow on the distribution circuit - are also presented and analyzed.

  4. Installation of solar PV systems in Sri Lanka

    SciTech Connect

    Fernando, M.P.T.P.

    1995-10-01

    The tropical country of Sri Lanka has hydroelectric power plants sufficient to provide electricity to only 40% of its 25,000 villages. The electric power needs of the average Sri Lankan rural communities are basic: three or four lights to illuminate their house and a power supply for their televisions. Solar radiation is abundant throughout the year. To take advantage of this resource, the Sarvodaya Rural Technical Services launched a Solar PV pilot demonstration project in the rural areas not served by the electric grid. The systems were being installed on an individual residence basis and funded by loans. Social and cultural problems which have arisen during the course of the project have slowed its implementation. This study identifies the problems and makes recommendations to resolve the current problems and avoid new ones.

  5. Comparative analysis of DG and solar PV water pumping system

    NASA Astrophysics Data System (ADS)

    Tharani, Kusum; Dahiya, Ratna

    2016-03-01

    Looking at present day electricity scenario, there is a major electricity crisis in rural areas. The farmers are still dependant on the monsoon rains for their irrigation needs and livestock maintenance. Some of the agrarian population has opted to use Diesel Generators for pumping water in their fields. But taking into consideration the economics and environmental conditions, the above choice is not suitable for longer run. An effort to shift from non-renewable sources such as diesel to renewable energy source such as solar has been highlighted. An approximate comparative analysis showing the life cycle costs of a PV pumping system with Diesel Generator powered water pumping is done using MATLAB/STMULTNK.

  6. Interconnection Assessment Methodology and Cost Benefit Analysis for High-Penetration PV Deployment in the Arizona Public Service System

    SciTech Connect

    Baggu, Murali; Giraldez, Julieta; Harris, Tom; Brunhart-Lupo, Nicholas; Lisell, Lars; Narang, David

    2015-06-14

    In an effort to better understand the impacts of high penetrations of photovoltaic (PV) generators on distribution systems, Arizona Public Service and its partners completed a multi-year project to develop the tools and knowledge base needed to safely and reliably integrate high penetrations of utility- and residential-scale PV. Building upon the APS Community Power Project-Flagstaff Pilot, this project investigates the impact of PV on a representative feeder in northeast Flagstaff. To quantify and catalog the effects of the estimated 1.3 MW of PV that will be installed on the feeder (both smaller units at homes and large, centrally located systems), high-speed weather and electrical data acquisition systems and digital 'smart' meters were designed and installed to facilitate monitoring and to build and validate comprehensive, high-resolution models of the distribution system. These models are being developed to analyze the impacts of PV on distribution circuit protection systems (including coordination and anti-islanding), predict voltage regulation and phase balance issues, and develop volt/VAr control schemes. This paper continues from a paper presented at the 2014 IEEE PVSC conference that described feeder model evaluation and high penetration advanced scenario analysis, specifically feeder reconfiguration. This paper presents results from Phase 5 of the project. Specifically, the paper discusses tool automation; interconnection assessment methodology and cost benefit analysis.

  7. PV Standards Work: Photovoltaic System and Component Certification, Test Facility Accreditation, and Solar Photovoltaic Energy Systems International Standards

    SciTech Connect

    Basso, T. S.; Chalmers, S.; Barikmo, H. O.

    2005-11-01

    This paper discusses efforts led by two companies (PowerMark Corporation and Sunset Technologies Inc.) to support both U.S. domestic and international photovoltaic (PV) system and component certification and test facility accreditation programs and the operation of the International Electrotechnical Commission (IEC) Technical Committee 82 (TC-82) Photovoltaic Energy Systems. International and national PV certification/accreditation programs are successfully facilitating entry of only the highest quality PV products into the marketplace. Standards also continue to be a cornerstone for assuring global PV product conformity assessment, reducing non-tariff trade barriers, and ultimately improving PV products while lowering cost.

  8. Evaluation of neural network based real time maximum power tracking controller for PV system

    SciTech Connect

    Hiyama, Takashi; Kouzuma, Shinichi; Imakubo, Tomofumi; Ortmeyer, T.H.

    1995-09-01

    This paper presents a neural network based maximum power tracking controller for interconnected PV systems to commercial power sources. The neural network is utilized to identify the optimal operating voltage of the PV system. The controller generates the control signal in real time, and the control signal is fed back to the voltage control loop of the inverter to shift the terminal voltage of the PV system to the identified optimal one, which yields the maximum power generation. The controller is a PI type one. The proportion an the integral gains are set to their optimal values to achieve the fast response and also to prevent the overshoot and also the undershoot. The continuous measurement is required for the open circuit voltage on the monitoring cell, and also for the terminal voltage of the PV system. Because of the accurate identification of the optimal operating voltage of the PV system, more than 99% power is drawn for the actual maximum power.

  9. Establishment of key grid-connected performance index system for integrated PV-ES system

    NASA Astrophysics Data System (ADS)

    Li, Q.; Yuan, X. D.; Qi, Q.; Liu, H. M.

    2016-08-01

    In order to further promote integrated optimization operation of distributed new energy/ energy storage/ active load, this paper studies the integrated photovoltaic-energy storage (PV-ES) system which is connected with the distribution network, and analyzes typical structure and configuration selection for integrated PV-ES generation system. By combining practical grid- connected characteristics requirements and technology standard specification of photovoltaic generation system, this paper takes full account of energy storage system, and then proposes several new grid-connected performance indexes such as paralleled current sharing characteristic, parallel response consistency, adjusting characteristic, virtual moment of inertia characteristic, on- grid/off-grid switch characteristic, and so on. A comprehensive and feasible grid-connected performance index system is then established to support grid-connected performance testing on integrated PV-ES system.

  10. Analysis of concentrating PV-T systems for the commercial/industrial sector. Volume II. PV-T state-of-the-art survey and site/application pair selection and analysis

    SciTech Connect

    Schwinkendorf, W.E.

    1984-09-01

    As part of a project to develop feasibility assessments, design procedures, and reference designs for total energy systems that could use actively cooled concentrating photovoltaic collectors, a survey was conducted to provide an overview of available photovoltaic-thermal (PV-T) technology. General issues associated with the design and installation of a PV-T system are identified. Electrical and thermal efficiencies for the line-focus Fresnel, the linear parabolic trough, and the point-focus Fresnel collectors are specified as a function of operating temperature, ambient temperature, and insolation. For current PV-T technologies, the line-focus Fresnel collector proved to have the highest thermal and electrical efficiencies, lowest array cost, and lowest land area requirement. But a separate feasibility analysis involving 11 site/application pairs showed that for most applications, the cost of the photovoltaic portion of a PV-T system is not recovered through the displacement of an electrical load, and use of a thermal-only system to displace the thermal load would be a more economical alternative. PV-T systems are not feasible for applications that have a small thermal load, a large steam requirement, or a high load return temperature. SAND82-7157/3 identifies the technical issues involved in designing a photovoltaic-thermal system and provides guidance for resolving such issues. Detailed PV-T system designs for three selected applications and the results of a trade-off study for these applications are presented in SAND82-7157/4. A summary of the major results of this entire study and conclusions concerning PV-T systems and applications is presented in SAND82-7157/1.

  11. Cooperative Voltage Control Method by Power Factor Control of PV Systems and LRT

    NASA Astrophysics Data System (ADS)

    Kawasaki, Shoji; Kanemoto, Noriaki; Taoka, Hisao; Matsuki, Junya; Hayashi, Yasuhiro

    Recently, the number of system interconnection of the renewable energy sources (RES) such as the photovoltaic generation (PV) and wind power generation is increasing drastically, and there is in danger of changing the voltages in a distribution system by the precipitous output variation of RESs. In this study, the authors propose one voltage control method of the distribution system by the power factor control of plural PV systems in consideration of cooperation with the load ratio control transformer (LRT) of laggard control response installed beforehand in the distribution system. In the proposed method, the slow voltage variation is controlled by LRT, and the steep voltage variation uncontrollable by LRT is controlled by plural PV systems, as a result, all the node voltages are controllable within the proper limits. In order to verify the validity of the proposed method, the numerical calculations are carried out by using an analytical model of distribution system which interconnected PV systems.

  12. Experimental Performance Investigation of Photovoltaic/Thermal (PV-T) System

    NASA Astrophysics Data System (ADS)

    Ozgoren, M.; Aksoy, M. H.; Bakir, C.; Dogan, S.

    2013-04-01

    Photovoltaic solar cells convert light energy from the sun into electricity. Photovoltaic cells are produced by semi-conducting materials to convert the energy into electricity and during this process heat is absorbed by the solar radiation. This heat causes a loss of electricity generation efficiencies.In this study, an experimental setup was designed and established to test two separate photovoltaic panel systems with alone PV and with water cooling system PV/T to examine the heat effect on PV systems. The absorbed heat energy behind the photovoltaic cell's surface in insulated ambient was removed by means of a water cooling system and the tests for both systems were simultaneously performed along the July 2011. It is found that without active water cooling, the temperature of the PV module was higher during day time and solar cells could only achieve around 8% conversion efficiency. On the other hand, when the PV module was operated with active water cooling condition, the temperature dropped significantly, leading to an increase in the efficiency of solarcells as much as 13.6%. Gained from absorbed solar heat and maximum thermal conversion efficiencies of the system are determined as 49% and 51% for two different mass flow rates. It is observed that water flow rate is effective on the increasing the conversion efficiency as well as absorption and transitionrates of cover glass in PV/T (PV-Thermal) collector, the insulation material and cell efficiency. As a conclusion, the conversion efficiency of the PV system with water cooling might be improved on average about 10%. Therefore, it is recommended that PV system should be designed with most efficient type cooling system to enhance the efficiency and to decrease the payback period.

  13. Solar PV water pumping system for rural development in Nepal: Problems and prospects

    SciTech Connect

    Shrestha, J.N.

    1996-12-31

    Although PV water pumping systems have high initial costs, they require virtually no maintenance, require no fuel and thus save foreign exchange. They are easy to install and operate, have no moving parts and hence are highly reliable and durable and are modular in nature for future expansion, PV systems are found to be competitive with conventional diesel generator systems. Despite the above mentioned facts policy makers are still not convinced that solar PV water pumping systems can support rural development. This paper gives reasons for the failures of some solar PV water pumping projects in Nepal. Development of solar electricity totaling about 800 KWp in Nepal is briefly highlighted. Basic preconditions are identified for the successful operation of solar PV water pumping systems. The findings of successful solar PV water pumping systems are highlighted with specific reference to socio-economic impacts in the rural society. Subsidy policy of the government on solar PV water pumping systems is analyzed. Development of a spontaneous market for community solar PV water pumping system is analyzed. Suggestions are given on how solar PV water pumping system can be made more affordable by village people. Typical Nepalese rural areas are found to be suitable and economical for SPVWPS. Site evaluation procedure is given. Finally, the paper indicates the important of training for the local people in installation, operation and routine maintenance to ensure the reliability of the SPVWPS. The paper emphasizes the involvement of end-users from the very beginning of planning stage of SPVWPS. Detail comparison between a SPVWPS and an equivalent diesel generator is also indicated in the paper.

  14. Innovative Ballasted Flat Roof Solar PV Racking System

    SciTech Connect

    Peek, Richard T.

    2014-12-15

    The objective of this project was to reduce the cost of racking for PV solar on flat commercial rooftops. Cost reductions would come from both labor savings and material savings related to the installation process. The rack would need to accommodate the majority of modules available on the market. Cascade Engineering has a long history of converting traditional metal type applications over to plastic. Injection molding of plastics have numerous advantages including selection of resin for the application, placing the material exactly where it is needed, designing in features that will speed up the installation process, and weight reduction of the array. A plastic rack would need to meet the requirements of UL2703, Mounting systems, mounting devices, clamping/retention devices, and ground lugs for use with flat-plate photovoltaic modules and panels. Comparing original data to the end of project racking design, racking material costs were reduced 50% and labor costs reduced 64%. The racking product accommodates all 60 and 72 cell panels on the market, meets UL2703 requirements, contributes only 1.3 pounds per square foot of weight to the array, requires little ballast to secure the array, automatically grounds the module when the module is secured, stacks/nests well for shipping/fewer lifts to the roof, provides integrated wire routing, allows water to drain on the roof, and accommodates various seismic roof connections. Project goals were achieved as noted in the original funding application.

  15. Economics and performance of PV hybrid power systems: Three case studies

    SciTech Connect

    Rosenthal, A.L.; Durand, S.J.; Thomas, M.G.; Post, H.N.

    1998-07-01

    The Photovoltaic Systems Assistance Center (PVSAC) of Sandia National Laboratories (SNL) has been supporting the development and implementation of off-grid PV hybrid power systems for many years. Technical support has included: refining hardware; understanding system design techniques; obtaining operation and maintenance data; studying use of energy produced. As part of the program, the PVSAC has provided technical expertise on hybrid systems to many federal agencies including the National Park Service, the Forest Service, the Bureau of Land Management, and the Department of Defense. The goal of these partnerships has been to ensure that reliable and safe PV hybrid systems are specified and procured. At present, a critical review of performance and costs of several representative PV hybrid systems is underway. This paper presents a summary of the performance and economical analyses conducted on three PV hybrid systems.

  16. Small PV Systems Performance Evaluation at NREL's Outdoor Test Facility Using the PVUSA Power Rating Method

    SciTech Connect

    Adelstein, J.; Sekulic, W.

    2005-11-01

    The PV Systems Performance and Reliability R & D group currently has seven grid-tied 1-2 kilowatt PV systems deployed at NREL's Outdoor Test Facility (OTF) and two 6 kilowatt systems mounted on the roof of NREL's Solar Energy Research Facility (SERF). The systems, which employ several PV module technologies including crystalline silicon (c-Si), amorphous silicon (a-Si), cadmium telluride (CdTe), and copper indium diselenide (CIS), are being monitored to determine the long-term performance and reliability of the modules and arrays under actual field conditions. The length of observation ranges from 2 months for our newest system to 11 years for our oldest systems. The annual degradation and seasonal fluctuation of the systems' power output are calculated using the PV for Utility-Scale Applications (PVUSA) power rating regression model.

  17. Mathematical modeling of photovoltaic thermal PV/T system with v-groove collector

    NASA Astrophysics Data System (ADS)

    Zohri, M.; Fudholi, A.; Ruslan, M. H.; Sopian, K.

    2017-07-01

    The use of v-groove in solar collector has a higher thermal efficiency in references. Dropping the working heat of photovoltaic panel was able to raise the electrical efficiency performance. Electrical and thermal efficiency were produced by photovoltaic thermal (PV/T) system concurrently. Mathematical modeling based on steady-state thermal analysis of PV/T system with v-groove was conducted. With matrix inversion method, the energy balance equations are explained by means of the investigative method. The comparison results show that in the PV/T system with the V-groove collector is higher temperature, thermal and electrical efficiency than other collectors.

  18. Joint U.S./Brazilian hybrid power system (wind-PV-diesel) on Marajo Island

    SciTech Connect

    Leboeuf, C.; Taylor, R.W.; Corbus, D.; Moszkowicz, M.; Lima, J.; Ribeiro, C.

    1995-09-01

    A cooperative renewable energy project is underway between the U.S. Department of Energy (through the National Renewable Energy Laboratory, NREL), and the Federal Republic of Brazil (through the Centro de Pesquisas de Energia Eletrica, CEPEL). The objectives of this joint US/Brazilian program are to establish technical, institutional, and economic confidence in using renewable energy systems to meet the needs of the people of rural Brazil, to build ongoing partnerships beneficial to both countries, and to demonstrate the potential for large-scale rural electrification through the use of renewable energy systems. Phase 1 of this program resulted in the deployment of more than 700 photovoltaic (PV) electric lighting systems in the Brazilian states of Pernambuco and Ceara. Phase 2 of the program extends the pilot project into six additional Brazilian states and demonstrates a wider variety of stand-alone end uses, including the use of wind electric power generation for selected sites and applications. Additionally, Phase 2 also includes the development of two hybrid village power systems, including one comprising PV, wind, battery, and diesel power sources. This paper focuses on this hybrid system, which is located in the Amazon River delta.

  19. Realworld maximum power point tracking simulation of PV system based on Fuzzy Logic control

    NASA Astrophysics Data System (ADS)

    Othman, Ahmed M.; El-arini, Mahdi M. M.; Ghitas, Ahmed; Fathy, Ahmed

    2012-12-01

    In the recent years, the solar energy becomes one of the most important alternative sources of electric energy, so it is important to improve the efficiency and reliability of the photovoltaic (PV) systems. Maximum power point tracking (MPPT) plays an important role in photovoltaic power systems because it maximize the power output from a PV system for a given set of conditions, and therefore maximize their array efficiency. This paper presents a maximum power point tracker (MPPT) using Fuzzy Logic theory for a PV system. The work is focused on the well known Perturb and Observe (P&O) algorithm and is compared to a designed fuzzy logic controller (FLC). The simulation work dealing with MPPT controller; a DC/DC Ćuk converter feeding a load is achieved. The results showed that the proposed Fuzzy Logic MPPT in the PV system is valid.

  20. Amp-hour counting control for PV hybrid power systems

    SciTech Connect

    Hund, T.D.; Thompson, B.

    1997-06-01

    The performance of an amp-hour (Ah) counting battery charge control algorithm has been defined and tested using the Digital Solar Technologies MPR-9400 microprocessor based PV hybrid charge controller. This work included extensive field testing of the charge algorithm on flooded lead-antimony and valve regulated lead-acid (VRLA) batteries. The test results after one-year have demonstrated that PV charge utilization, battery charge control, and battery state of charge (SOC) has been significantly improved by providing maximum charge to the batteries while limiting battery overcharge to manufacturers specifications during variable solar resource and load periods.

  1. Life cycle cost analysis of a stand-alone PV system in rural Kenya

    NASA Astrophysics Data System (ADS)

    Daly, Emma

    The purpose of this quantitative research study was to determine the economic feasibility of a stand-alone PV system to electrify a rural area in Kenya. The research conducted involved a comprehensive review of all the relevant literature associated with the study. Methodologies were extrapolated from this extensive literature to develop a model for the complete design and economic analysis of a stand-alone PV system. A women's center in rural Kenya was used as a worked example to demonstrate the workings of the model. The results suggest that electrifying the center using a stand-alone PV system is an economically viable option which is encouraging for the surrounding area. This model can be used as a business model to determine the economic feasibility of a stand-alone PV system in alternative sites in Kenya.

  2. PV Systems Reliability Final Technical Report: Ground Fault Detection

    SciTech Connect

    Lavrova, Olga; Flicker, Jack David; Johnson, Jay

    2016-01-01

    We have examined ground faults in PhotoVoltaic (PV) arrays and the efficacy of fuse, current detection (RCD), current sense monitoring/relays (CSM), isolation/insulation (Riso) monitoring, and Ground Fault Detection and Isolation (GFID) using simulations based on a Simulation Program with Integrated Circuit Emphasis SPICE ground fault circuit model, experimental ground faults installed on real arrays, and theoretical equations.

  3. Plug and Play Components for Building Integrated PV Systems, Phase II Final Report, 20 February 2003 - 31 May 2007

    SciTech Connect

    Rowell, D.

    2008-04-01

    Progress by Schott Solar, Inc. under NREL's PV Manufacturing R&D Project. Details progress on meter-interconnect device; free-standing mounting system; dark I-V curves to unearth problems with PV module strings; new 34-V version of ASE-300 PV module; and updated source-circuit protectors.

  4. An investigation of the maximum penetration level of a photovoltaic (PV) system into a traditional distribution grid

    NASA Astrophysics Data System (ADS)

    Chalise, Santosh

    Although solar photovoltaic (PV) systems have remained the fastest growing renewable power generating technology, variability as well as uncertainty in the output of PV plants is a significant issue. This rapid increase in PV grid-connected generation presents not only progress in clean energy but also challenges in integration with traditional electric power grids which were designed for transmission and distribution of power from central stations. Unlike conventional electric generators, PV panels do not have rotating parts and thus have no inertia. This potentially causes a problem when the solar irradiance incident upon a PV plant changes suddenly, for example, when scattered clouds pass quickly overhead. The output power of the PV plant may fluctuate nearly as rapidly as the incident irradiance. These rapid power output fluctuations may then cause voltage fluctuations, frequency fluctuations, and power quality issues. These power quality issues are more severe with increasing PV plant power output. This limits the maximum power output allowed from interconnected PV plants. Voltage regulation of a distribution system, a focus of this research, is a prime limiting factor in PV penetration levels. The IEEE 13-node test feeder, modeled and tested in the MATLAB/Simulink environment, was used as an example distribution feeder to analyze the maximum acceptable penetration of a PV plant. The effect of the PV plant's location was investigated, along with the addition of a VAR compensating device (a D-STATCOM in this case). The results were used to develop simple guidelines for determining an initial estimate of the maximum PV penetration level on a distribution feeder. For example, when no compensating devices are added to the system, a higher level of PV penetration is generally achieved by installing the PV plant close to the substation. The opposite is true when a VAR compensator is installed with the PV plant. In these cases, PV penetration levels over 50% may be

  5. Designing PV Incentive Programs to Promote System Performance: AReview of Current Practice

    SciTech Connect

    Barbose, Galen; Wiser, Ryan; Bolinger, Mark

    2006-11-12

    Some stakeholders continue to voice concerns about the performance of customer-sited photovoltaic (PV) systems, particularly because these systems typically receive financial support through ratepayer- or publicly-funded programs. Although much remains to be understood about the extent and specific causes of poor PV system performance, several studies of the larger programs and markets have shed some light on the issue. An evaluation of the California Energy Commission (CEC)'s Emerging Renewables Program, for example, found that 7% of systems, in a sample of 95, had lower-than-expected power output due to shading or soiling (KEMA 2005). About 3% of a larger sample of 140 systems were not operating at all or were operating well below expected output, due to failed equipment, faulty installation workmanship, and/or a lack of basic maintenance. In a recent evaluation of the other statewide PV incentive program in California, the Self-Generation Incentive Program, 9 of 52 projects sampled were found to have annual capacity factors less than 14.5%, although reasons for these low capacity factors generally were not identified (Itron 2005). Studies of PV systems in Germany and Japan, the two largest PV markets worldwide, have also revealed some performance problems associated with issues such as shading, equipment and installation defects, inverter failure, and deviations from module manufacturers' specifications (Otani et al. 2004, Jahn & Nasse 2004). Although owners of PV systems have an inherent incentive to ensure that their systems perform well, many homeowners and building operators may lack the necessary information and expertise to carry out this task effectively. Given this barrier, and the responsibility of PV incentive programs to ensure that public funds are prudently spent, these programs should (and often do) play a critical role in promoting PV system performance. Performance-based incentives (PBIs), which are based on actual energy production rather than

  6. Performance of modular grid connected PV systems with undersized inverters in Portugal and the Netherlands

    SciTech Connect

    Kil, A.J.; Weiden, T.C.J. van der

    1994-12-31

    Preliminary results on the design and performance of three multi-array grid connected PV systems on flat roofs are presented. From the results it can be concluded that inverters can at least be undersized to 65% of the PV peak power without any significant loss of energy production. These results confirm the findings from model calculations carried out as a part of the design process.

  7. Hybrid photovoltaic/thermal (PV/T) solar systems simulation with Simulink/Matlab

    SciTech Connect

    da Silva, R.M.; Fernandes, J.L.M.

    2010-12-15

    The purpose of this work consists in thermodynamic modeling of hybrid photovoltaic-thermal (PV/T) solar systems, pursuing a modular strategy approach provided by Simulink/Matlab. PV/T solar systems are a recently emerging solar technology that allows for the simultaneous conversion of solar energy into both electricity and heat. This type of technology present some interesting advantages over the conventional ''side-by-side'' thermal and PV solar systems, such as higher combined electrical/thermal energy outputs per unit area, and a more uniform and aesthetical pleasant roof area. Despite the fact that early research on PV/T systems can be traced back to the seventies, only recently it has gained a renewed impetus. In this work, parametric studies and annual transient simulations of PV/T systems are undertaken in Simulink/Matlab. The obtained results show an average annual solar fraction of 67%, and a global overall efficiency of 24% (i.e. 15% thermal and 9% electrical), for a typical four-person single-family residence in Lisbon, with p-Si cells, and a collector area of 6 m{sup 2}. A sensitivity analysis performed on the PV/T collector suggests that the most important variable that should be addressed to improve thermal performance is the photovoltaic (PV) module emittance. Based on those results, some additional improvements are proposed, such as the use of vacuum, or a noble gas at low-pressure, to allow for the removal of PV cells encapsulation without air oxidation and degradation, and thus reducing the PV module emittance. Preliminary results show that this option allows for an 8% increase on optical thermal efficiency, and a substantial reduction of thermal losses, suggesting the possibility of working at higher fluid temperatures. The higher working temperatures negative effect in electrical efficiency was negligible, due to compensation by improved optical properties. The simulation results are compared with experimental data obtained from other authors

  8. Experimental investigations of hybrid PV/Spiral flow thermal collector system performance using Al2O3/water nanofluid

    NASA Astrophysics Data System (ADS)

    Gangadevi, R.; Vinayagam, B. K.; Senthilraja, S.

    2017-05-01

    In this paper, the PV/T (Photovoltaic thermal unit) system is investigated experimentally to examine the thermal, electrical and overall efficiency by circulating Al2O3/water nanofluid of 1wt% and 2wt% with an optimum flow rate of 40L/H. The overall efficiency of PVT system is largely influenced by various factors such as heat due to photovoltaic action; energy radiated at the infrared wavelength of the solar spectrum, solar irradiance, mounting structure, tilt angle, wind speed direction, Ambient temperature and panel material composition. However, the major factor is considered in this study to extract the heat generated in the PV panel by using nanofluid as a coolant to increase the overall system efficiency. Therefore, the result shows that by using 2 wt% Al2O3/water nanofluid the electrical efficiency, thermal efficiency and overall efficiency of the PVT system enhanced by 13%, 45%, and 58% respectively compared with water.

  9. A simple model of PV system performance and its use in fault detection

    SciTech Connect

    Firth, S.K.; Lomas, K.J.; Rees, S.J.

    2010-04-15

    Results are presented from a monitoring study of the performance of a sample of UK domestic PV systems. Five-minute average climatic and performance data was recorded for 27 PV systems at two sites for up to 2 years of operation. On average, the annual energy losses due to faults were 3.6% (Site A, first year of operation), 6.6% (Site A, second year of operation) and 18.9% (Site B, first year of operation). Simple empirical models are constructed to describe the performance of the PV systems under 'normal operation' (when no faults occur). New analysis techniques are developed which estimate the energy losses of four different fault categories: sustained zero efficiency faults; brief zero efficiency faults; shading; and non-zero efficiency non-shading faults. The results demonstrate that faults have the potential to cause significant energy losses in domestic PV systems. The benefits of applying the data analysis techniques described in this work to PV system clusters and other urban micro-generation technologies are discussed. (author)

  10. Energy 101: Solar PV

    ScienceCinema

    None

    2016-07-12

    Solar photovoltaic (PV) systems can generate clean, cost-effective power anywhere the sun shines. This video shows how a PV panel converts the energy of the sun into renewable electricity to power homes and businesses.

  11. Energy 101: Solar PV

    SciTech Connect

    2011-01-01

    Solar photovoltaic (PV) systems can generate clean, cost-effective power anywhere the sun shines. This video shows how a PV panel converts the energy of the sun into renewable electricity to power homes and businesses.

  12. Reliability assessment for components of large scale photovoltaic systems

    NASA Astrophysics Data System (ADS)

    Ahadi, Amir; Ghadimi, Noradin; Mirabbasi, Davar

    2014-10-01

    Photovoltaic (PV) systems have significantly shifted from independent power generation systems to a large-scale grid-connected generation systems in recent years. The power output of PV systems is affected by the reliability of various components in the system. This study proposes an analytical approach to evaluate the reliability of large-scale, grid-connected PV systems. The fault tree method with an exponential probability distribution function is used to analyze the components of large-scale PV systems. The system is considered in the various sequential and parallel fault combinations in order to find all realistic ways in which the top or undesired events can occur. Additionally, it can identify areas that the planned maintenance should focus on. By monitoring the critical components of a PV system, it is possible not only to improve the reliability of the system, but also to optimize the maintenance costs. The latter is achieved by informing the operators about the system component's status. This approach can be used to ensure secure operation of the system by its flexibility in monitoring system applications. The implementation demonstrates that the proposed method is effective and efficient and can conveniently incorporate more system maintenance plans and diagnostic strategies.

  13. RTDS implementation of an improved sliding mode based inverter controller for PV system.

    PubMed

    Islam, Gazi; Muyeen, S M; Al-Durra, Ahmed; Hasanien, Hany M

    2016-05-01

    This paper proposes a novel approach for testing dynamics and control aspects of a large scale photovoltaic (PV) system in real time along with resolving design hindrances of controller parameters using Real Time Digital Simulator (RTDS). In general, the harmonic profile of a fast controller has wide distribution due to the large bandwidth of the controller. The major contribution of this paper is that the proposed control strategy gives an improved voltage harmonic profile and distribute it more around the switching frequency along with fast transient response; filter design, thus, becomes easier. The implementation of a control strategy with high bandwidth in small time steps of Real Time Digital Simulator (RTDS) is not straight forward. This paper shows a good methodology for the practitioners to implement such control scheme in RTDS. As a part of the industrial process, the controller parameters are optimized using particle swarm optimization (PSO) technique to improve the low voltage ride through (LVRT) performance under network disturbance. The response surface methodology (RSM) is well adapted to build analytical models for recovery time (Rt), maximum percentage overshoot (MPOS), settling time (Ts), and steady state error (Ess) of the voltage profile immediate after inverter under disturbance. A systematic approach of controller parameter optimization is detailed. The transient performance of the PSO based optimization method applied to the proposed sliding mode controlled PV inverter is compared with the results from genetic algorithm (GA) based optimization technique. The reported real time implementation challenges and controller optimization procedure are applicable to other control applications in the field of renewable and distributed generation systems. Copyright © 2015 ISA. Published by Elsevier Ltd. All rights reserved.

  14. Fuzzy comprehensive evaluation for grid-connected performance of integrated distributed PV-ES systems

    NASA Astrophysics Data System (ADS)

    Lv, Z. H.; Li, Q.; Huang, R. W.; Liu, H. M.; Liu, D.

    2016-08-01

    Based on the discussion about topology structure of integrated distributed photovoltaic (PV) power generation system and energy storage (ES) in single or mixed type, this paper focuses on analyzing grid-connected performance of integrated distributed photovoltaic and energy storage (PV-ES) systems, and proposes a comprehensive evaluation index system. Then a multi-level fuzzy comprehensive evaluation method based on grey correlation degree is proposed, and the calculations for weight matrix and fuzzy matrix are presented step by step. Finally, a distributed integrated PV-ES power generation system connected to a 380 V low voltage distribution network is taken as the example, and some suggestions are made based on the evaluation results.

  15. Capacity Value of PV and Wind Generation in the NV Energy System

    SciTech Connect

    Lu, Shuai; Diao, Ruisheng; Samaan, Nader A.; Etingov, Pavel V.

    2014-03-21

    Calculation of photovoltaic (PV) and wind power capacity values is important for estimating additional load that can be served by new PV or wind installations in the electrical power system. It also is the basis for assigning capacity credit payments in systems with markets. Because of variability in solar and wind resources, PV and wind generation contribute to power system resource adequacy differently from conventional generation. Many different approaches to calculating PV and wind generation capacity values have been used by utilities and transmission operators. Using the NV Energy system as a study case, this report applies peak-period capacity factor (PPCF) and effective load carrying capability (ELCC) methods to calculate capacity values for renewable energy sources. We show the connection between the PPCF and ELCC methods in the process of deriving a simplified approach that approximates the ELCC method. This simplified approach does not require generation fleet data and provides the theoretical basis for a quick check on capacity value results of PV and wind generation. The diminishing return of capacity benefit as renewable generation increases is conveniently explained using the simplified capacity value approach.

  16. Determination of Duty Cycle for Energy Storage Systems in a PV Smoothing Application

    SciTech Connect

    Schoenwald, David A.; Ellison, James

    2016-04-01

    This report supplements the document, "Protocol for Uniformly Measuring and Expressing the Performance of Energy Storage Systems," issued in a revised version in April 2016 (see [4]), which will include the photovoltaic (PV) smoothing application for an energy storage system (ESS). This report provides the background and documentation associated with the determination of a duty cycle for an ESS operated in a PV smoothing application for the purpose of measuring and expressing ESS performance in accordance with the ESS performance protocol. ACKNOWLEDGEMENTS The authors gratefully acknowledge the support of Dr. Imre Gyuk, program manager for the DOE Energy Storage Systems Program. The authors would also like to express their appreciation to all the stakeholders who participated as members of the PV Smoothing Subgroup. Without their thoughtful input and recommendations, the definitions, metrics, and duty cycle provided in this report would not have been possible. A complete listing of members of the PV Smoothing Subgroup appears in the first chapter of this report. Special recognition should go to the staffs at Pacific Northwest National Laboratory (PNNL) and Sandia National Laboratories (SNL) in collaborating on this effort. In particular, Mr. David Conover and Dr. Vish Viswanathan of PNNL and Dr. Summer Ferreira of SNL were especially helpful in their suggestions for the determination of a duty cycle for the PV Smoothing application.

  17. Integrating Solar PV in Utility System Operations: Analytical Framework and Arizona Case Study

    SciTech Connect

    Wu, Jing; Botterud, Audun; Mills, Andrew; Zhou, Zhi; Hodge, Bri-Mathias; Mike, Heaney

    2015-06-01

    A systematic framework is proposed to estimate the impact on operating costs due to uncertainty and variability in renewable resources. The framework quantifies the integration costs associated with subhourly variability and uncertainty as well as day-ahead forecasting errors in solar PV (photovoltaics) power. A case study illustrates how changes in system operations may affect these costs for a utility in the southwestern United States (Arizona Public Service Company). We conduct an extensive sensitivity analysis under different assumptions about balancing reserves, system flexibility, fuel prices, and forecasting errors. We find that high solar PV penetrations may lead to operational challenges, particularly during low-load and high solar periods. Increased system flexibility is essential for minimizing integration costs and maintaining reliability. In a set of sensitivity cases where such flexibility is provided, in part, by flexible operations of nuclear power plants, the estimated integration costs vary between $1.0 and $4.4/MWh-PV for a PV penetration level of 17%. The integration costs are primarily due to higher needs for hour-ahead balancing reserves to address the increased sub-hourly variability and uncertainty in the PV resource. (C) 2015 Elsevier Ltd. All rights reserved.

  18. Investigation of Synergy Between Electrochemical Capacitors, Flywheels, and Batteries in Hybrid Energy Storage for PV Systems

    SciTech Connect

    Miller, John; Sibley, Lewis, B.; Wohlgemuth, John

    1999-06-01

    This report describes the results of a study that investigated the synergy between electrochemical capacitors (ECs) and flywheels, in combination with each other and with batteries, as energy storage subsystems in photovoltaic (PV) systems. EC and flywheel technologies are described and the potential advantages and disadvantages of each in PV energy storage subsystems are discussed. Seven applications for PV energy storage subsystems are described along with the potential market for each of these applications. A spreadsheet model, which used the net present value method, was used to analyze and compare the costs over time of various system configurations based on flywheel models. It appears that a synergistic relationship exists between ECS and flywheels. Further investigation is recommended to quantify the performance and economic tradeoffs of this synergy and its effect on overall system costs.

  19. Value of PV systems experiments. Volume 1: A preliminary assessment of the lessons learned from nine intermediate-size systems

    NASA Astrophysics Data System (ADS)

    Thomas, M.

    1984-08-01

    Nine intermediate-size photovoltaic (PV) experiments sponsored by the US Department of Energy (DOE) are reviewed. Five variations of PV technology were represented in the experiments: (1) flat plate; (2) flat plate with mirror enhancement; (3) combined photovoltaic/thermal (PV/T) parabolic trough concentrator; (4) combined line-focus Fresnel lens concentrator and thermal; and (5) point-focus Fresnel lens concentrator. The system costs and installation costs are reviewed. The characteristics and electrical performance of the systems are described. Operation and maintenance data are given.

  20. Value of PV systems experiments. Volume I. A preliminary assessment of the lessons learned from nine intermediate-size systems

    SciTech Connect

    Thomas, M.

    1984-08-01

    This report reviews nine intermediate-size photovoltaic (PV) experiments sponsored by the US Department of Energy (DOE). Five variations of PV technology were represented in the experiments: (1) flat plate; (2) flat plate with mirror enhancement; (3) combined photovoltaic/thermal (PV/T) parabolic trough concentrator; (4) combined line-focus Fresnel lens concentrator and thermal; and (5) point-focus Fresnel lens concentrator. The system costs and installation costs are reviewed. The characteristics and electrical performance of the systems are described. Operation and maintenance data are given.

  1. Comparison of four MPPT techniques for PV systems

    NASA Astrophysics Data System (ADS)

    Atik, L.; Petit, P.; Sawicki, J. P.; Ternifi, Z. T.; Bachir, G.; Aillerie, M.

    2016-07-01

    The working behavior of a module / PV array is non-linear and highly dependent on working conditions. As a given condition, there is only one point at which the level of available power at its output is maximum. This point varies with time, enlightenment and temperature. To ensure optimum operation, the use of MPPT control allows us to extract the maximum power. This paper presents a comparative study of four widely-adopted MPPT algorithms, such as Perturb and Observe, Incremental Conductance, Measurements of the variation of the open circuit voltage or of the short-circuit current. Their performance is evaluated using, for all these techniques. In particular, this study compares the behaviors of each technique in presence of solar irradiation variations and temperature fluctuations. These MPPT techniques will be compared using the Matlab / Simulink tool.

  2. Comparison of four MPPT techniques for PV systems

    SciTech Connect

    Atik, L. Ternifi, Z. T.; Petit, P.; Sawicki, J. P.; Aillerie, M.; Bachir, G.

    2016-07-25

    The working behavior of a module / PV array is non-linear and highly dependent on working conditions. As a given condition, there is only one point at which the level of available power at its output is maximum. This point varies with time, enlightenment and temperature. To ensure optimum operation, the use of MPPT control allows us to extract the maximum power. This paper presents a comparative study of four widely-adopted MPPT algorithms, such as Perturb and Observe, Incremental Conductance, Measurements of the variation of the open circuit voltage or of the short-circuit current. Their performance is evaluated using, for all these techniques. In particular, this study compares the behaviors of each technique in presence of solar irradiation variations and temperature fluctuations. These MPPT techniques will be compared using the Matlab / Simulink tool.

  3. PV System 'Availability' as a Reliability Metric -- Improving Standards, Contract Language and Performance Models

    SciTech Connect

    Klise, Geoffrey T.; Hill, Roger; Walker, Andy; Dobos, Aron; Freeman, Janine

    2016-11-21

    The use of the term 'availability' to describe a photovoltaic (PV) system and power plant has been fraught with confusion for many years. A term that is meant to describe equipment operational status is often omitted, misapplied or inaccurately combined with PV performance metrics due to attempts to measure performance and reliability through the lens of traditional power plant language. This paper discusses three areas where current research in standards, contract language and performance modeling is improving the way availability is used with regards to photovoltaic systems and power plants.

  4. Public Response to Residential Grid-Tied PV Systems in Colorado: A Qualitative Market Assessment

    SciTech Connect

    Farhar, B. C.; Buhrmann, J.

    1998-07-01

    The early adopters of residential grid-tied photovoltaics (PV) have complex motivations to pay today's costs, including altruistic, environmental, and financial reasons. Focused interviews were conducted with a self-selected purposive sample interested in purchasing 2-kW or 3-kW PV systems with an installed cost of $8,000 to $12,000. The sample tended to be men or married couples ranging in age from their early thirties to their mid-eighties; professionals, managers, or small business owners; relatively financially secure, with experience with energy efficiency and renewable energy. Product attributes they preferred were net metering, warranties, guarantees, utility financing, maintenance, an option to own or lease, a battery option, and an aesthetically pleasing system. Potential PV customers needed more information before making a purchase decision.

  5. Robust nonlinear controller design to improve the stability of a large scale photovoltaic system

    NASA Astrophysics Data System (ADS)

    Islam, Gazi Md. Saeedul

    Recently interest in photovoltaic (PV) power generation systems is increasing rapidly and the installation of large PV systems or large groups of PV systems that are interconnected with the utility grid is accelerating despite their high cost and low efficiency due to environmental issues and depletions of fossil fuels. Most of the photovoltaic (PV) applications are grid connected. Existing power systems may face the stability problems because of the high penetration of PV systems to the grid. Therefore, more stringent grid codes are being imposed by the energy regulatory bodies for grid integration of PV plants. Recent grid codes dictate that PV plants need to stay connected with the power grid during the network faults because of their increased power penetration level. This requires the system to have large disturbance rejection capability to protect the system and provide dynamic grid support. This thesis presents a new control method to enhance the steady-state and transient stabilities of a grid connected large scale photovoltaic (PV) system. A new control coordination scheme is also presented to reduce the power mismatch during the fault condition in order to limit the fault currents, which is one of the salient features of this study. The performance of the overall system is analyzed using laboratory standard power system simulation software PSCAD/EMTDC.

  6. What Factors Affect the Prices of Low-Priced U.S. Solar PV Systems?

    SciTech Connect

    Nemet, Gregory F.; O'Shaughnessy, Eric; Wiser, Ryan; Darghouth, Naïm R.; Barbose, Galen; Gillingham, Ken; Rai, Varun

    2016-08-01

    The price of solar PV systems has declined rapidly, yet there are some much lower-priced systems than others. This study explores the factors leading some systems to be so much lower priced than others. Using a data set of 42,611 residential-scale PV systems installed in the U.S. in 2013, we use quantile regressions to estimate the importance of factors affecting the installed prices for low-priced (LP) systems (those at the 10th percentile) in comparison to median-priced systems. We find that the value of solar to consumers–a variable that accounts for subsidies, electric rates, and PV generation levels–is associated with lower prices for LP systems but higher prices for median priced systems. Conversely, systems installed in new home construction are associated with lower prices at the median but higher prices for LP. Other variables have larger cost-reducing effects on LP than on median priced systems: systems installed in Arizona and Florida, as well as commercial and thin film systems. In contrast, the following have a smaller effect on prices for LP systems than median priced systems: tracking systems, self-installations, systems installed in Massachusetts, the system size, and installer experience. These results highlight the complex factors at play that lead to LP systems and shed light into how such LP systems can come about.

  7. Performance of a 268Wp stand-alone PV system test facility

    SciTech Connect

    Adanu, K.G.

    1994-12-31

    This paper reports on studies carried out on a 268 Wp stand-alone PV test facility installed at the University of Ghana. Parameters measured include solar irradiance, ambient temperature, cell temperature, array voltage, battery voltage, and energy output from array. An automatic data acquisition system was used to record the data. The purpose of this study was to determine the effect on performance of a PV array due to seasonal climatic changes: for example, effect due to dust during the period when dust-laden winds blow from the Sahara desert to most sub-saharan West African countries. The reduced intensity of the solar radiation as would be expected reduced the total array output during the harmattan and the rainy seasons. No visible changes were observed in the PV modules themselves over the period of study, but one of the junction boxes attached to the modules had become severely corroded.

  8. What factors affect the prices of low-priced U.S. solar PV systems?

    DOE PAGES

    Nemet, Gregory F.; O'Shaughnessy, Eric; Wiser, Ryan; ...

    2017-08-09

    The price of solar PV systems has declined rapidly, yet there are some much lower-priced systems than others. This study explores the factors that determine prices in these low-priced (LP) systems. Using a data set of 42,611 residential-scale PV systems installed in the U.S. in 2013, we use quantile regressions to estimate the importance of factors affecting the installed prices for LP systems (those at the 10th percentile) in comparison to median-priced systems. We find that the value of solar to consumers-a variable that accounts for subsidies, electric rates, and PV generation levels-is associated with lower prices for LP systemsmore » but higher prices for median priced systems. Conversely, systems installed in new home construction are associated with lower prices at the median but higher prices for LP. Other variables have larger price-reducing effects on LP than on median priced systems: systems installed in Arizona and Florida, as well as commercial and thin film systems. In contrast, the following have a smaller effect on prices for LP systems than median priced systems: tracking systems, self-installations, systems installed in Massachusetts, the system size, and installer experience. Furthermore, these results highlight the complex factors at play that lead to LP systems and shed light into how such LP systems can come about.« less

  9. Recent advances in outdoor performance evaluation of PV systems

    SciTech Connect

    Quintana, M.A.; King, D.L.; Cannon, J.E.; Woodworth, J.R.; Boyson, W.E.; Adams, N.P.; Ellibee, D.E.

    1992-12-31

    Sandia`s Photovoltaic Technology Laboratory (PTEL) routinely performs outdoor tests of a variety of one-sun and concentrator PV modules. The authors experience is that while outdoor testing has its own set of problems, it can produce results that are more directly applicable to ``field`` conditions than testing in solar simulators. They have recently improved both the hardware and software at the PTEL to improve their accuracy and to deal with the special set of problems encountered in outdoor testing. Improvements in hardware include a computer-controlled solar tracker that allows us to test arrays up to 21 m{sup 2} in size; infrared imaging of modules; and electronic loads that allow us to test components with outputs up to 1,800 watts. Improvements in software include real-time monitoring of data collection; a relational data base that has improved the reliability of test setups, operations and analyses; and a standardized reporting process that relates module performance to a number of environmental parameters.

  10. Recent advances in outdoor performance evaluation of PV systems

    NASA Astrophysics Data System (ADS)

    Quintana, M. A.; King, D. L.; Cannon, J. E.; Woodworth, J. R.; Boyson, W. E.; Adams, N. P.; Ellibee, D. E.

    Sandia's Photovoltaic Technology Laboratory (PTEL) routinely performs outdoor tests of a variety of one-sun and concentrator PV modules. The authors' experience is that while outdoor testing has its own set of problems, it can produce results that are more directly applicable to 'field' conditions than testing in solar simulators. They have recently improved both the hardware and software at the PTEL to improve their accuracy and to deal with the special set of problems encountered in outdoor testing. Improvements in hardware include a computer-controlled solar tracker that allows us to test arrays up to 21 sq m in size, infrared imaging of modules, and electronic loads that allow us to test components with outputs up to 1,800 watts. Improvements in software include real-time monitoring of data collection; a relational data base that has improved the reliability of test setups, operations, and analyses; and a standardized reporting process that relates module performance to a number of environmental parameters.

  11. PLL Based Energy Efficient PV System with Fuzzy Logic Based Power Tracker for Smart Grid Applications.

    PubMed

    Rohini, G; Jamuna, V

    This work aims at improving the dynamic performance of the available photovoltaic (PV) system and maximizing the power obtained from it by the use of cascaded converters with intelligent control techniques. Fuzzy logic based maximum power point technique is embedded on the first conversion stage to obtain the maximum power from the available PV array. The cascading of second converter is needed to maintain the terminal voltage at grid potential. The soft-switching region of three-stage converter is increased with the proposed phase-locked loop based control strategy. The proposed strategy leads to reduction in the ripple content, rating of components, and switching losses. The PV array is mathematically modeled and the system is simulated and the results are analyzed. The performance of the system is compared with the existing maximum power point tracking algorithms. The authors have endeavored to accomplish maximum power and improved reliability for the same insolation of the PV system. Hardware results of the system are also discussed to prove the validity of the simulation results.

  12. Investigation of power values of PV rooftop systems based on heat gain reduction

    NASA Astrophysics Data System (ADS)

    Chenvidhya, Tanokkorn; Seapan, Manit; Parinya, Panom; Wiengmoon, Buntoon; Chenvidhya, Dhirayut; Songprakorp, Roongrojana; Limsakul, Chamnan; Sangpongsanont, Yaowanee; Tannil, Nittaya

    2015-09-01

    PV rooftop system can generally be installed to produce electricity for the domestic house, office, small enterprise as well as factory. Such a system has direct useful for reducing peak load, meanwhile it also provides shaded area on the roof and hence the heat gain into the building is reduced. This study aims to investigate the shading effect on reduction of heat transfer into the building. The 49 kWp of PV rooftop system has been installed on the deck of the office building located in the middle of Thailand where the latitude of 14 ° above the equator. The estimation of heat gain into the building due to the solar irradiation throughout a day for one year has been carried out, before and after the installation of the PV rooftop system. Then the Newton's law of cooling is applied to calculate the heat gain. The calculation and the measurement of the heat reduction are compared. Finally, the indirect benefit of the PV rooftop system installed is evaluated in terms of power value.

  13. PLL Based Energy Efficient PV System with Fuzzy Logic Based Power Tracker for Smart Grid Applications

    PubMed Central

    Rohini, G.; Jamuna, V.

    2016-01-01

    This work aims at improving the dynamic performance of the available photovoltaic (PV) system and maximizing the power obtained from it by the use of cascaded converters with intelligent control techniques. Fuzzy logic based maximum power point technique is embedded on the first conversion stage to obtain the maximum power from the available PV array. The cascading of second converter is needed to maintain the terminal voltage at grid potential. The soft-switching region of three-stage converter is increased with the proposed phase-locked loop based control strategy. The proposed strategy leads to reduction in the ripple content, rating of components, and switching losses. The PV array is mathematically modeled and the system is simulated and the results are analyzed. The performance of the system is compared with the existing maximum power point tracking algorithms. The authors have endeavored to accomplish maximum power and improved reliability for the same insolation of the PV system. Hardware results of the system are also discussed to prove the validity of the simulation results. PMID:27294189

  14. Solar PV Project Financing: Regulatory and Legislative Challenges for Third-Party PPA System Owners

    SciTech Connect

    Kollins, K.; Speer, B.; Cory, K.

    2009-11-01

    Residential and commercial end users of electricity who want to generate electricity using on-site solar photovoltaic (PV) systems face challenging initial and O&M costs. The third-party ownership power purchase agreement (PPA) finance model addresses these and other challenges. It allows developers to build and own PV systems on customers? properties and sell power back to customers. However, third-party electricity sales commonly face five regulatory challenges. The first three challenges involve legislative or regulatory definitions of electric utilities, power generation equipment, and providers of electric services. These definitions may compel third-party owners of solar PV systems to comply with regulations that may be cost prohibitive. Third-party owners face an additional challenge if they may not net meter, a practice that provides significant financial incentive to owning solar PV systems. Finally, municipalities and cooperatives worry about the regulatory implications of allowing an entity to sell electricity within their service territories. This paper summarizes these challenges, when they occur, and how they have been addressed in five states. This paper also presents alternative to the third-party ownership PPA finance model, including solar leases, contractual intermediaries, standardized contract language, federal investment tax credits, clean renewable energy bonds, and waived monopoly powers.

  15. Analysis of concentrating PV-T systems for the commercial/industrial sector. Volume III. Technical issues and design guidance

    SciTech Connect

    Schwinkendorf, W.E.

    1984-09-01

    This report provide appropriate guidance for addressing the major technical issues associated with the design and installation of a photovoltaic-thermal (PV-T) system. Nomographs are presented for developing preliminary sizing and costing, and issues associated with specific components and the overall design of the electrical and mechanical system are discussed. SAND82-7157/2 presents a review of current PV-T technology and operating systems and a study of potential PV-T applications. Detailed PV-T system designs for three selected applications and the results of a trade-off study for these applications are presented in SAND82-7157/4. A summary of the major results of this entire study and conclusions concerning PV-T systems and applications is presented in SAND82-7157/1.

  16. Design considerations and performance of Maspeth a-Si PV system

    NASA Astrophysics Data System (ADS)

    Stafford, Byron

    1994-06-01

    This paper describes the design and early performance of a 17-kWp(ac) amorphous silicon (a-Si) photovoltaic (PV) system in Maspeth, New York. The system started operating in June, 1993. The system is mounted on the roof of a warehouse operated by the New York City Transit Authority. The system was designed and installed by Integrated Power Corporation using a unique ballast-weighted system configuration with no roof penetrations. Same-band-gap tandem a-Si modules from United Solar Systems Corporation are used. The PV modules face south and slope 10 degrees from horizontal. This paper estimates the monthly system performance and reports the system's performance during the first three months of operation.

  17. Optimization of PV/WIND/DIESEL Hybrid Power System in HOMER for Rural Electrification

    NASA Astrophysics Data System (ADS)

    Hassan, Q.; Jaszczur, M.; Abdulateef, J.

    2016-09-01

    A large proportion of the world's population lives in remote rural areas that are geographically isolated and sparsely populated. The present study is based on modeling, computer simulation and optimization of hybrid power generation system in the rural area in Muqdadiyah district of Diyala state, Iraq. Two renewable resources, namely, solar photovoltaic (PV) and wind turbine (WT) are considered. The HOMER software is used to study and design the proposed hybrid energy system model. Based on simulation results, it has been found that renewable energy sources perhaps replace the conventional energy sources and would be a feasible solution for the generation of electric power at remote locations with a reasonable investment. The hybrid power system solution to electrify the selected area resulted in a least-cost combination of the hybrid power system that can meet the demand in a dependable manner at a cost about (0.321/kWh). If the wind resources in the study area at the lower stage, it's not economically viable for a wind turbine to generate the electricity.

  18. Sustainable electricity generation by solar pv/diesel hybrid system without storage for off grids areas

    NASA Astrophysics Data System (ADS)

    Azoumah, Y.; Yamegueu, D.; Py, X.

    2012-02-01

    Access to energy is known as a key issue for poverty reduction. The electrification rate of sub Saharan countries is one of the lowest among the developing countries. However this part of the world has natural energy resources that could help raising its access to energy, then its economic development. An original "flexy energy" concept of hybrid solar pv/diesel/biofuel power plant, without battery storage, is developed in order to not only make access to energy possible for rural and peri-urban populations in Africa (by reducing the electricity generation cost) but also to make the electricity production sustainable in these areas. Some experimental results conducted on this concept prototype show that the sizing of a pv/diesel hybrid system by taking into account the solar radiation and the load/demand profile of a typical area may lead the diesel generator to operate near its optimal point (70-90 % of its nominal power). Results also show that for a reliability of a PV/diesel hybrid system, the rated power of the diesel generator should be equal to the peak load. By the way, it has been verified through this study that the functioning of a pv/Diesel hybrid system is efficient for higher load and higher solar radiation.

  19. Intelligent Energy Management System for PV-Battery-based Microgrids in Future DC Homes

    NASA Astrophysics Data System (ADS)

    Chauhan, R. K.; Rajpurohit, B. S.; Gonzalez-Longatt, F. M.; Singh, S. N.

    2016-06-01

    This paper presents a novel intelligent energy management system (IEMS) for a DC microgrid connected to the public utility (PU), photovoltaic (PV) and multi-battery bank (BB). The control objectives of the proposed IEMS system are: (i) to ensure the load sharing (according to the source capacity) among sources, (ii) to reduce the power loss (high efficient) in the system, and (iii) to enhance the system reliability and power quality. The proposed IEMS is novel because it follows the ideal characteristics of the battery (with some assumptions) for the power sharing and the selection of the closest source to minimize the power losses. The IEMS allows continuous and accurate monitoring with intelligent control of distribution system operations such as battery bank energy storage (BBES) system, PV system and customer utilization of electric power. The proposed IEMS gives the better operational performance for operating conditions in terms of load sharing, loss minimization, and reliability enhancement of the DC microgrid.

  20. Battery and charge controller evaluations in small stand-alone PV systems

    NASA Astrophysics Data System (ADS)

    Woodworth, J. R.; Thomas, M. G.; Stevens, J. W.; Dunlop, J. L.; Swamy, M. R.; Demetrius, L.; Harrington, S. R.

    1994-12-01

    We report the results of two separate long-term tests of batteries and charge controllers in small stand-alone PV systems. In these experiments, seven complete systems were tested for two years at each of two locations: Sandia National Laboratories in Albuquerque and the Florida Solar Energy Center in Cape Canaveral, Florida. Each system contained a PV array, flooded-lead-acid battery, a charge controller and a resistive load. Performance of the systems was strongly influenced by the difference in solar irradiance at the two sites, with some batteries at Sandia exceeding manufacturer's predictions for cycle life. System performance was strongly correlated with regulation reconnect voltage (R(sup 2) correlation coefficient = 0.95) but only weakly correlated with regulation voltage. We will also discuss details of system performance, battery lifetime and battery water consumption.

  1. Battery and charge controller evaluations in small stand-alone PV systems

    SciTech Connect

    Woodworth, J.R.; Thomas, M.G.; Stevens, J.W.; Dunlop, J.L.; Swamy, M.R.; Demetrius, L.; Harrington, S.R.

    1994-07-01

    We report the results of to separate long-term tests of batteries and charge controllers in small stand-alone PV systems. In these experiments, seven complete systems were tested for two years at each of two locations: Sandia National Laboratories in Albuquerque and the Florida Solar Energy Center in Cape Canaveral, Florida. Each system contained a PV array, flooded-lead-acid battery, a charge controller and a resistive load. Performance of the systems was strongly influenced by the difference in solar irradiance at the two sites, with some batteries at Sandia exceeding manufacturer`s predictions for cycle life. System performance was strongly correlated with regulation reconnect voltage (R{sup 2} correlation coefficient = 0.95) but only weakly correlated with regulation voltage. We will also discuss details of system performance, battery lifetime and battery water consumption.

  2. Performance analysis of ‘Perturb and Observe’ and ‘Incremental Conductance’ MPPT algorithms for PV system

    NASA Astrophysics Data System (ADS)

    Lodhi, Ehtisham; Lodhi, Zeeshan; Noman Shafqat, Rana; Chen, Fieda

    2017-07-01

    Photovoltaic (PV) system usually employed The Maximum power point tracking (MPPT) techniques for increasing its efficiency. The performance of the PV system perhaps boosts by controlling at its apex point of power, in this way maximal power can be given to load. The proficiency of a PV system usually depends upon irradiance, temperature and array architecture. PV array shows a non-linear style for V-I curve and maximal power point on V-P curve also varies with changing environmental conditions. MPPT methods grantees that a PV module is regulated at reference voltage and to produce entire usage of the maximal output power. This paper gives analysis between two widely employed Perturb and Observe (P&O) and Incremental Conductance (INC) MPPT techniques. Their performance is evaluated and compared through theoretical analysis and digital simulation on the basis of response time and efficiency under varying irradiance and temperature condition using Matlab/Simulink.

  3. Bulk Heterojunction Solar Cells for Large-Area PV Fabrication on Flexible Substrates

    NASA Astrophysics Data System (ADS)

    Waldauf, C.; Dennler, G.; Schilinsky, P.; Brabec, C. J.

    Photovoltaics (PV) is the harvesting of energy from sunlight and conversion into electrical power. This technology is being increasingly recognized as one of the key components in our future global energy scenario. The limited resources of fossil fuel and the steadily increasing costs to supply fossil fuels to the market give a natural limit when renewable energies will begin to kick in as major energy suppliers. In addition, the detrimental long-term effects of CO2 and other emissions from burning fossil fuels into our atmosphere underscore the multiple benefits of developing renewable energy resources and commercializing them.

  4. Mitigating the Detrimental Impacts of Solar PV Penetration on Electric Power Transmission Systems

    NASA Astrophysics Data System (ADS)

    Prakash, Nitin

    At present, almost 70% of the electric energy in the United States is produced utilizing fossil fuels. Combustion of fossil fuels contributes CO 2 to the atmosphere, potentially exacerbating the impact on global warming. To make the electric power system (EPS) more sustainable for the future, there has been an emphasis on scaling up generation of electric energy from wind and solar resources. These resources are renewable in nature and have pollution free operation. Various states in the US have set up different goals for achieving certain amount of electrical energy to be produced from renewable resources. The Southwestern region of the United States receives significant solar radiation throughout the year. High solar radiation makes concentrated solar power and solar PV the most suitable means of renewable energy production in this region. However, the majority of the projects that are presently being developed are either residential or utility owned solar PV plants. This research explores the impact of significant PV penetration on the steady state voltage profile of the electric power transmission system. This study also identifies the impact of PV penetration on the dynamic response of the transmission system such as rotor angle stability, frequency response and voltage response after a contingency. The light load case of spring 2010 and the peak load case of summer 2018 have been considered for analyzing the impact of PV. If the impact is found to be detrimental to the normal operation of the EPS, mitigation measures have been devised and presented in the thesis. Commercially available software tools/packages such as PSLF, PSS/E, DSA Tools have been used to analyze the power network and validate the results.

  5. Xanthomonas campestris pv. vesicatoria Secretes Proteases and Xylanases via the Xps Type II Secretion System and Outer Membrane Vesicles.

    PubMed

    Solé, Magali; Scheibner, Felix; Hoffmeister, Anne-Katrin; Hartmann, Nadine; Hause, Gerd; Rother, Annekatrin; Jordan, Michael; Lautier, Martine; Arlat, Matthieu; Büttner, Daniela

    2015-09-01

    Many plant-pathogenic bacteria utilize type II secretion (T2S) systems to secrete degradative enzymes into the extracellular milieu. T2S substrates presumably mediate the degradation of plant cell wall components during the host-pathogen interaction and thus promote bacterial virulence. Previously, the Xps-T2S system from Xanthomonas campestris pv. vesicatoria was shown to contribute to extracellular protease activity and the secretion of a virulence-associated xylanase. The identities and functions of additional T2S substrates from X. campestris pv. vesicatoria, however, are still unknown. In the present study, the analysis of 25 candidate proteins from X. campestris pv. vesicatoria led to the identification of two type II secreted predicted xylanases, a putative protease and a lipase which was previously identified as a virulence factor of X. campestris pv. vesicatoria. Studies with mutant strains revealed that the identified xylanases and the protease contribute to virulence and in planta growth of X. campestris pv. vesicatoria. When analyzed in the related pathogen X. campestris pv. campestris, several T2S substrates from X. campestris pv. vesicatoria were secreted independently of the T2S systems, presumably because of differences in the T2S substrate specificities of the two pathogens. Furthermore, in X. campestris pv. vesicatoria T2S mutants, secretion of T2S substrates was not completely absent, suggesting the contribution of additional transport systems to protein secretion. In line with this hypothesis, T2S substrates were detected in outer membrane vesicles, which were frequently observed for X. campestris pv. vesicatoria. We, therefore, propose that extracellular virulence-associated enzymes from X. campestris pv. vesicatoria are targeted to the Xps-T2S system and to outer membrane vesicles. The virulence of plant-pathogenic bacteria often depends on TS2 systems, which secrete degradative enzymes into the extracellular milieu. T2S substrates are being

  6. Xanthomonas campestris pv. vesicatoria Secretes Proteases and Xylanases via the Xps Type II Secretion System and Outer Membrane Vesicles

    PubMed Central

    Solé, Magali; Scheibner, Felix; Hoffmeister, Anne-Katrin; Hartmann, Nadine; Hause, Gerd; Rother, Annekatrin; Jordan, Michael; Lautier, Martine; Arlat, Matthieu

    2015-01-01

    ABSTRACT Many plant-pathogenic bacteria utilize type II secretion (T2S) systems to secrete degradative enzymes into the extracellular milieu. T2S substrates presumably mediate the degradation of plant cell wall components during the host-pathogen interaction and thus promote bacterial virulence. Previously, the Xps-T2S system from Xanthomonas campestris pv. vesicatoria was shown to contribute to extracellular protease activity and the secretion of a virulence-associated xylanase. The identities and functions of additional T2S substrates from X. campestris pv. vesicatoria, however, are still unknown. In the present study, the analysis of 25 candidate proteins from X. campestris pv. vesicatoria led to the identification of two type II secreted predicted xylanases, a putative protease and a lipase which was previously identified as a virulence factor of X. campestris pv. vesicatoria. Studies with mutant strains revealed that the identified xylanases and the protease contribute to virulence and in planta growth of X. campestris pv. vesicatoria. When analyzed in the related pathogen X. campestris pv. campestris, several T2S substrates from X. campestris pv. vesicatoria were secreted independently of the T2S systems, presumably because of differences in the T2S substrate specificities of the two pathogens. Furthermore, in X. campestris pv. vesicatoria T2S mutants, secretion of T2S substrates was not completely absent, suggesting the contribution of additional transport systems to protein secretion. In line with this hypothesis, T2S substrates were detected in outer membrane vesicles, which were frequently observed for X. campestris pv. vesicatoria. We, therefore, propose that extracellular virulence-associated enzymes from X. campestris pv. vesicatoria are targeted to the Xps-T2S system and to outer membrane vesicles. IMPORTANCE The virulence of plant-pathogenic bacteria often depends on TS2 systems, which secrete degradative enzymes into the extracellular milieu. T2S

  7. Design and evaluation of hybrid wind/PV/diesel power systems for Brazilian applications

    SciTech Connect

    McGowan, J.G.; Manwell, J.F.; Avelar, C.; Warner, C.

    1996-12-31

    This paper presents a summary of a study centered on the design and evaluation of hybrid wind/PV/diesel systems for remote locations in Brazil. The objective of this work was to evaluate high reliability hybrid power systems that have been designed for the lowest life cycle costs. The technical and economic analysis of the hybrid wind/PV/diesel systems was carried out using HYBRID2, a computational code developed at the University of Massachusetts in conjunction with the National Renewable Energy Laboratory (NREL). After a summary of a generalized design procedure for such systems based on the use of this code, a systematic parametric evaluation of a representative design case for a village power system in Brazil is presented. As summarized in the paper, the performance and economic effects of key design parameters are illustrated. 8 refs., 10 figs.

  8. Design and application of PV power system for 100w to 10kw

    SciTech Connect

    Matlin, R.W.

    1982-06-01

    Photovoltaic systems are economically viable in remote areas where grid power is not available and where power requirements are modest. PV systems provide power for water pumping, navigation aids, and residential electrification. Water pumping applications are projected to provide the largest market. The world's largest PV pumping unit, a 25Kw centrifugal pump system used to irrigate 80 acres of corn in Nebraska, is shown. Volumetric style ''jack pumps'' have been installed in the Upper Volta, and in Arizona. Remote residential AC power systems at the Hopi reservation, and a navigational aid system in the St. Lawrence Seaway are also demonstrated. Life cycle costing has shown that it is preferable to use deep cycle batteries.

  9. PV system reliability: lessons learned from a fleet of 333 systems

    NASA Astrophysics Data System (ADS)

    Kaushik, A.; Golnas, A.

    2011-09-01

    The levelized cost of energy (LCOE) from PV systems can be reduced by maximizing the energy production of existing/future PV plants through increased availability. This can be achieved by detailed study of root cause and failure analysis of component failures leading to a systematic progress towards improving the reliability of various sub-systems. SunEdison owns/operates ~500 sites across the world and systematically collects field failure data in addition to power output and weather data. Analysis of this information allows following-up on corrective actions to eliminate/minimize the re-occurrence of failures and leads to continuous improvements. This paper will analyze some of the key findings from the system failures as follows: - Inverter failures not only cause most of the system outages, but also result in substantial energy losses. Component failures in PCBs and inverter software/firmware bugs are the most common root cause of system outages - From a systemic root cause perspective, lack of robust quality systems at multiple levels of the supply chain is quite evident, which points toward the need for collectively inculcating the quality culture at every stage of the supply chain - This paper will try to establish the need for "Continuous Improvement Process" (CIP) where systemic issues are confronted and solutions are internalized in the operating procedures as the only path to improving component reliability - For a given level of reliability, cost associated with servicing the plant becomes critical. This paper highlights the importance of using "cost of ownership" metrics for making procurement decisions

  10. Performance Modeling and Testing of Distributed Electronics in PV Systems; NREL (National Renewable Energy Laboratory)

    SciTech Connect

    Deline, C.

    2015-03-18

    Computer modeling is able to predict the performance of distributed power electronics (microinverters, power optimizers) in PV systems. However, details about partial shade and other mismatch must be known in order to give the model accurate information to go on. This talk will describe recent updates in NREL’s System Advisor Model program to model partial shading losses with and without distributed power electronics, along with experimental validation results. Computer modeling is able to predict the performance of distributed power electronics (microinverters, power optimizers) in PV systems. However, details about partial shade and other mismatch must be known in order to give the model accurate information to go on. This talk will describe recent updates in NREL’s System Advisor Model program to model partial shading losses.

  11. Optimization of a stand-alone Solar PV-Wind-DG Hybrid System for Distributed Power Generation at Sagar Island

    NASA Astrophysics Data System (ADS)

    Roy, P. C.; Majumder, A.; Chakraborty, N.

    2010-10-01

    An estimation of a stand-alone solar PV and wind hybrid system for distributed power generation has been made based on the resources available at Sagar island, a remote area distant to grid operation. Optimization and sensitivity analysis has been made to evaluate the feasibility and size of the power generation unit. A comparison of the different modes of hybrid system has been studied. It has been estimated that Solar PV-Wind-DG hybrid system provides lesser per unit electricity cost. Capital investment is observed to be lesser when the system run with Wind-DG compared to Solar PV-DG.

  12. Distribution system model calibration with big data from AMI and PV inverters

    SciTech Connect

    Peppanen, Jouni; Reno, Matthew J.; Broderick, Robert J.; Grijalva, Santiago

    2016-03-03

    Efficient management and coordination of distributed energy resources with advanced automation schemes requires accurate distribution system modeling and monitoring. Big data from smart meters and photovoltaic (PV) micro-inverters can be leveraged to calibrate existing utility models. This paper presents computationally efficient distribution system parameter estimation algorithms to improve the accuracy of existing utility feeder radial secondary circuit model parameters. The method is demonstrated using a real utility feeder model with advanced metering infrastructure (AMI) and PV micro-inverters, along with alternative parameter estimation approaches that can be used to improve secondary circuit models when limited measurement data is available. Lastly, the parameter estimation accuracy is demonstrated for both a three-phase test circuit with typical secondary circuit topologies and single-phase secondary circuits in a real mixed-phase test system.

  13. Distribution system model calibration with big data from AMI and PV inverters

    DOE PAGES

    Peppanen, Jouni; Reno, Matthew J.; Broderick, Robert J.; ...

    2016-03-03

    Efficient management and coordination of distributed energy resources with advanced automation schemes requires accurate distribution system modeling and monitoring. Big data from smart meters and photovoltaic (PV) micro-inverters can be leveraged to calibrate existing utility models. This paper presents computationally efficient distribution system parameter estimation algorithms to improve the accuracy of existing utility feeder radial secondary circuit model parameters. The method is demonstrated using a real utility feeder model with advanced metering infrastructure (AMI) and PV micro-inverters, along with alternative parameter estimation approaches that can be used to improve secondary circuit models when limited measurement data is available. Lastly, themore » parameter estimation accuracy is demonstrated for both a three-phase test circuit with typical secondary circuit topologies and single-phase secondary circuits in a real mixed-phase test system.« less

  14. Grid Integration of Single Stage Solar PV System using Three-level Voltage Source Converter

    NASA Astrophysics Data System (ADS)

    Hussain, Ikhlaq; Kandpal, Maulik; Singh, Bhim

    2016-08-01

    This paper presents a single stage solar PV (photovoltaic) grid integrated power generating system using a three level voltage source converter (VSC) operating at low switching frequency of 900 Hz with robust synchronizing phase locked loop (RS-PLL) based control algorithm. To track the maximum power from solar PV array, an incremental conductance algorithm is used and this maximum power is fed to the grid via three-level VSC. The use of single stage system with three level VSC offers the advantage of low switching losses and the operation at high voltages and high power which results in enhancement of power quality in the proposed system. Simulated results validate the design and control algorithm under steady state and dynamic conditions.

  15. PV-hybrid village power systems in Amazonia

    SciTech Connect

    Warner, C.L.; Taylor, R.W.; Ribeiro, C.M.; Moszkowicz, M.; Borba, A.J.V.

    1996-09-01

    The Brazilian Amazon region is an ideal location for isolated mini-grid systems. Hundreds of diesel systems have been installed to supply electricity to this sparsely populated region. However, the availability of renewable energy resources makes the Amazon well-suited to renewable energy systems. This paper describes the technical aspects of two hybrid systems being installed in this region through the cooperative effort of multiple partners: US Department of Energy, through NREL, and Brazilian CEPEL/Eletrobras and state electric utilities. The first system is a 50-kW photovoltaic-wind-battery hybrid and the second is a 50-kW photovoltaic-diesel-battery hybrid.

  16. ENVI-PV: An Interactive Web Client for Multi-Criteria Life Cycle Assessment of Photovoltaic Systems Worldwide

    SciTech Connect

    Perez-Lopez, Paula; Gschwind, Benoit; Blanc, Philippe; Frischknecht, Rolf; Stolz, Philippe; Durand, Yvonnick; Heath, Garvin; Menard, Lionel; Blanc, Isabelle

    2016-11-23

    Solar photovoltaics (PV) is the second largest source of new capacity among renewable energies. The worldwide capacity encompassed 135 GW in 2013 and is estimated to increase to 1721 GW in 2030 and 4674 GW in 2050, according to a prospective high-renewable scenario. To achieve this production level while minimizing environmental impacts, decision makers must have access to environmental performance data that reflect their high spatial variability accurately. We propose ENVI-PV (http://viewer.webservice-energy.org/project_iea), a new interactive tool that provides maps and screening level data, based on weighted average supply chains, for the environmental performance of common PV technologies. Environmental impacts of PV systems are evaluated according to a life cycle assessment approach. ENVI-PV was developed using a state-of-the-art interoperable and open standard Web Service framework from the Open Geospatial Consortium (OGC). It combines the latest life cycle inventories, published in 2015 by the International Energy Agency (IEA) under the Photovoltaic Power Systems Program (PVPS) Task 12, and some inventories previously published from Ecoinvent v2.2 database with solar irradiation estimates computed from the worldwide NASA SSE database. ENVI-PV is the first tool to propose a worldwide coverage of environmental performance of PV systems using a multi-criteria assessment. The user can compare the PV environmental performance to the environmental footprint of country electricity mixes. ENVI-PV is designed as an environmental interactive tool to generate PV technological options and evaluate their performance in different spatial and techno-economic contexts. Its potential applications are illustrated in this paper with several examples.

  17. A methodology to quantify and optimize time complementarity between hydropower and solar PV systems

    NASA Astrophysics Data System (ADS)

    Kougias, Ioannis; Szabó, Sándor; Monforti-Ferrario, Fabio; Huld, Thomas; Bódis, Katalin

    2016-04-01

    Hydropower and solar energy are expected to play a major role in achieving renewable energy sources' (RES) penetration targets. However, the integration of RES in the energy mix needs to overcome the technical challenges that are related to grid's operation. Therefore, there is an increasing need to explore approaches where different RES will operate under a synergetic approach. Ideally, hydropower and solar PV systems can be jointly developed in such systems where their electricity output profiles complement each other as much as possible and minimize the need for reserve capacities and storage costs. A straightforward way to achieve that is by optimizing the complementarity among RES systems both over time and spatially. The present research developed a methodology that quantifies the degree of time complementarity between small-scale hydropower stations and solar PV systems and examines ways to increase it. The methodology analyses high-resolution spatial and temporal data for solar radiation obtained from the existing PVGIS model (available online at: http://re.jrc.ec.europa.eu/pvgis/) and associates it with hydrological information of water inflows to a hydropower station. It builds on an exhaustive optimization algorithm that tests possible alterations of the PV system installation (azimuth, tilt) aiming to increase the complementarity, with minor compromises in the total solar energy output. The methodology has been tested in several case studies and the results indicated variations among regions and different hydraulic regimes. In some cases a small compromise in the solar energy output showed significant increases of the complementarity, while in other cases the effect is not that strong. Our contribution aims to present these findings in detail and initiate a discussion on the role and gains of increased complementarity between solar and hydropower energies. Reference: Kougias I, Szabó S, Monforti-Ferrario F, Huld T, Bódis K (2016). A methodology for

  18. In-situ defect detection systems for R2R flexible PV barrier films

    NASA Astrophysics Data System (ADS)

    Gao, F.; Muhamedsalih, H.; Tang, D.; Elrawemi, M.; Blunt, L.; Jiang, X.; Edge, S.; Bird, D.; Hollis, P.

    2015-08-01

    Film processing procedures by means of Roll-to-Roll (R2R) for barrier coatings can often result in PV barrier films being manufactured with significant quantities of defects, which results in lower efficiency and a short life span. In order to improve the process yield and product efficiency, it is desirable to develop an inspection system that can detect transparent barrier film defects in the production line during film processing. Off-line detection of defects in transparent PV barrier films is difficult and time consuming. Consequently, implementing an accurate in-situ defects inspection system in the production environment is even more challenging, since the requirements on positioning, fast measurement, long term stability and robustness against environmental disturbance are demanding. This paper reports on the development and deployment of two in-situ PV barrier films defect detection systems, one based on wavelength scanning interferometry (WSI) and the other on White Light Channeled Spectral Interferometry (WLCSI), and the integration into an R2R film processing line at the Centre for Process Innovation (CPI). The paper outlines the environmental vibration strategy for both systems, and the developed auto-focusing methodology for WSI. The systems have been tested and characterised and initial results compared to laboratory-based instrumentation are presented.

  19. Impact of Distributed Power Electronics on the Lifetime and Reliability of PV Systems

    DOE PAGES

    Deline, Christopher A; Olalla, Carlos; Maksimovic, Dragan; ...

    2017-04-26

    This paper quantifies the impact of distributed power electronics in photovoltaic (PV) systems in terms of end-of-life energy-capture performance and reliability. The analysis is based on simulations of PV installations over system lifetime at various degradation rates. It is shown how module-level or submodule-level power converters can mitigate variations in cell degradation over time, effectively increasing the system lifespan by 5-10 years compared with the nominal 25-year lifetime. An important aspect typically overlooked when characterizing such improvements is the reliability of distributed power electronics, as power converter failures may not only diminish energy yield improvements but also adversely affect themore » overall system operation. Failure models are developed, and power electronics reliability is taken into account in this work, in order to provide a more comprehensive view of the opportunities and limitations offered by distributed power electronics in PV systems. It is shown how a differential power-processing approach achieves the best mismatch mitigation performance and the least susceptibility to converter faults.« less

  20. Why do electricity policy and competitive markets fail to use advanced PV systems to improve distribution power quality?

    DOE PAGES

    McHenry, Mark P.; Johnson, Jay; Hightower, Mike

    2016-01-01

    The increasing pressure for network operators to meet distribution network power quality standards with increasing peak loads, renewable energy targets, and advances in automated distributed power electronics and communications is forcing policy-makers to understand new means to distribute costs and benefits within electricity markets. Discussions surrounding how distributed generation (DG) exhibits active voltage regulation and power factor/reactive power control and other power quality capabilities are complicated by uncertainties of baseline local distribution network power quality and to whom and how costs and benefits of improved electricity infrastructure will be allocated. DG providing ancillary services that dynamically respond to the networkmore » characteristics could lead to major network improvements. With proper market structures renewable energy systems could greatly improve power quality on distribution systems with nearly no additional cost to the grid operators. Renewable DG does have variability challenges, though this issue can be overcome with energy storage, forecasting, and advanced inverter functionality. This paper presents real data from a large-scale grid-connected PV array with large-scale storage and explores effective mitigation measures for PV system variability. As a result, we discuss useful inverter technical knowledge for policy-makers to mitigate ongoing inflation of electricity network tariff components by new DG interconnection requirements or electricity markets which value power quality and control.« less

  1. PV-hybrid village power systems in Amazonia

    SciTech Connect

    Warner, C.L.; Taylor, R.W.; Ribeiro, C.M.

    1996-05-01

    The Brazilian Amazon region is an ideal location for isolated mini-grid systems. Hundreds of diesel systems have been installed to supply electricity to this sparsely populated region. However, the availability of renewable energy resources makes the Amazon well-suited to renewable energy systems. This paper describes the technical aspects of two hybrid systems being installed in this region through the cooperative effort of multiple partners: U.S. Department of Energy, through NREL, and Brazilian CEPEL/Eletrobras and state electric utilities.

  2. Standardized large-scale H-1PV production process with efficient quality and quantity monitoring.

    PubMed

    Leuchs, Barbara; Roscher, Mandy; Müller, Marcus; Kürschner, Kathrin; Rommelaere, Jean

    2016-03-01

    The promising anticancer properties of rodent protoparvoviruses, notably H-1PV, have led to their clinical testing. This makes it necessary to produce highly pure, well-characterized virus batches in sufficient quantity. The present work focused on developing standardized production, purification, and characterization procedures as a basis for exploiting H-1PV both preclinically and in clinical trials for anticancer virotherapy. Two infection and two virus purification strategies were tested and the resulting virus preparations compared for their purity and full-, infectious-, and empty-particle contents. The adopted production process, which involves culturing and infecting NB-324K cells in 10-layer CellSTACK(®) chambers (1×10(3) infectious units per infected cell), is simple, scalable, and reproducible. Downstream processing to eliminate contaminating DNA and protein includes DNAse treatment, filtration, and two Iodixanol density-gradient centrifugations, the first gradient being a step gradient and the second, either a step (1×10(10) PFU/ml) or a continuous gradient (3×10(11) PFU/ml). A procedure was also developed for obtaining infectious particle-free preparations of empty virions for research purposes: cesium chloride density gradient centrifugation followed by UV irradiation (1×10(14) physical particles/ml). For quick, sensitive determination of physical particles (and hence, particle-to-infectivity ratios), a "Capsid-ELISA" was developed, based on a novel monoclonal antibody that specifically targets assembled capsids. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  3. Status and modeling improvements of hybrid wind/PV/diesel power systems for Brazilian applications

    SciTech Connect

    McGowan, J.G.; Manwell, J.F.; Avelar, C.; Taylor, R.

    1997-12-31

    This paper present a summary of the ongoing work on the modeling and system design of hybrid wind/PV/diesel systems for two different sites in the Amazonia region of Brazil. The work incorporates the latest resource data and is based on the use of the Hybrid2 simulation code developed by the University of Massachusetts and NREL. Details of the baseline operating hybrid systems are reviewed, and the results of the latest detailed hybrid system evaluation for each site are summarized. Based on the system modeling results, separate recommendations for system modification and improvements are made.

  4. The development and test of the PV concentrator system with electrical and thermal output

    NASA Astrophysics Data System (ADS)

    Okhorzina, A.; Kshalova, A.

    2017-08-01

    The article presents the control system of the PV concentrator system cooled by a heat sink. The installation is a hybrid system that generates heat and electrical energy from sunlight. The installation consists of a concentrator, photovoltaic modules and their cooling systems. It is necessary to control each part of the System to make it work effectively and get the highest amount of energy from it. The control system consists of subsystems, which control the sun tracking, cooling and the photovoltaic modules with accumulators.

  5. Grid tied PV/battery system architecture and power management for fast electric vehicle charging

    NASA Astrophysics Data System (ADS)

    Badawy, Mohamed O.

    The prospective spread of Electric vehicles (EV) and plug-in hybrid electric vehicles (PHEV) arises the need for fast charging rates. Higher charging rates requirements lead to high power demands, which cant be always supported by the grid. Thus, the use of on-site sources alongside the electrical grid for EVs charging is a rising area of interest. In this dissertation, a photovoltaic (PV) source is used to support the high power EVs charging. However, the PV output power has an intermittent nature that is dependable on the weather conditions. Thus, battery storage are combined with the PV in a grid tied system, providing a steady source for on-site EVs use in a renewable energy based fast charging station. Verily, renewable energy based fast charging stations should be cost effective, efficient, and reliable to increase the penetration of EVs in the automotive market. Thus, this Dissertation proposes a novel power flow management topology that aims on decreasing the running cost along with innovative hardware solutions and control structures for the developed architecture. The developed power flow management topology operates the hybrid system at the minimum operating cost while extending the battery lifetime. An optimization problem is formulated and two stages of optimization, i.e online and offline stages, are adopted to optimize the batteries state of charge (SOC) scheduling and continuously compensate for the forecasting errors. The proposed power flow management topology is validated and tested with two metering systems, i.e unified and dual metering systems. The results suggested that minimal power flow is anticipated from the battery storage to the grid in the dual metering system. Thus, the power electronic interfacing system is designed accordingly. Interconnecting bi-directional DC/DC converters are analyzed, and a cascaded buck boost (CBB) converter is chosen and tested under 80 kW power flow rates. The need to perform power factor correction (PFC) on

  6. Benchmarking Soft Costs for PV Systems in the United States (Presentation)

    SciTech Connect

    Ardani, K.

    2012-06-01

    This paper presents results from the first U.S. based data collection effort to quantify non-hardware, business process costs for PV systems at the residential and commercial scales, using a bottom-up approach. Annual expenditure and labor hour productivity data are analyzed to benchmark business process costs in the specific areas of: (1) customer acquisition; (2) permitting, inspection, and interconnection; (3) labor costs of third party financing; and (4) installation labor.

  7. An optimal control strategy for standalone PV system with Battery-Supercapacitor Hybrid Energy Storage System

    NASA Astrophysics Data System (ADS)

    Chong, Lee Wai; Wong, Yee Wan; Rajkumar, Rajprasad Kumar; Isa, Dino

    2016-11-01

    This paper proposes an optimal control strategy for a standalone PV system with Battery-Supercapacitor Hybrid Energy Storage System to prolong battery lifespan by reducing the dynamic stress and peak current demand of the battery. Unlike the conventional methods which only use either filtration based controller (FBC) or fuzzy logic controller (FLC), the proposed control strategy comprises of a low-pass filter (LPF) and FLC. Firstly, LPF removes the high dynamic components from the battery demand. FLC minimizes the battery peak current demand while constantly considering the state-of-charge of the supercapacitor. Particle swarm optimization (PSO) algorithm optimizes the membership functions of the FLC to achieve optimal battery peak current reduction. The proposed system is compared to the conventional system with battery-only storage and the systems with conventional control strategies (Rule Based Controller and FBC). The proposed system reduces the battery peak current, battery peak power, maximum absolute value of the rate of change of power and average absolute value of the rate of change of power by 16.05%, 15.19%, 77.01%, and 95.59%, respectively as compared to the conventional system with battery-only storage. Moreover, he proposed system increases the level of supercapacitor utilization up to 687.122% in comparison to the conventional control strategies.

  8. Design of A Grid Integrated PV System with MPPT Control and Voltage Oriented Controller using MATLAB/PLECES

    NASA Astrophysics Data System (ADS)

    Soreng, Bineeta; Behera, Pradyumna; Pradhan, Raseswari

    2017-08-01

    This paper presents model of a grid-integrated photovoltaic array with Maximum Power Point Tracker (MPPT) and voltage oriented controller. The MPPT of the PV array is usually an essential part of PV system as MPPT helps the operating point of the solar array to align its maximum power point. In this model, the MPPT along with a DC-DC converter lets a PV generator to produce continuous power, despite of the measurement conditions. The neutral-point-clamped converter (NPC) with a boost converter raises the voltage from the panels to the DC-link. An LCL-filter smoothens the current ripple caused by the PWM modulation of the grid-side inverter. In addition to the MPPT, the system has two more two controllers, such as voltage controller and a current controller. The voltage control has a PI controller to regulate the PV voltage to optimal level by controlling the amount of current injected into the boost stage. Here, the grid-side converter transfers the power from the DC-link into the grid and maintains the DC-link voltage. Three-phase PV inverters are used for off-grid or designed to create utility frequency AC. The PV system can be connected in series or parallel to get the desired output power. To justify the working of this model, the grid-integrated PV system has been designed in MATLAB/PLECS. The simulation shows the P-V curve of implemented PV Array consisting 4 X 20 modules, reactive, real power, grid voltage and current.

  9. 205 kW Photovoltaic (PV) System Installed on the U.S. Department of Energy’s Forrestal Building

    SciTech Connect

    2008-09-11

    The Forrestal PV system will provide a clean, domestic, renewable source of energy for the U.S. Department of Energy (DOE), and provide leadership in meeting Federal goals for increasing the use of renewable energy technologies.

  10. Dynamic Performance Comparison for MPPT-PV Systems using Hybrid Pspice/Matlab Simulation

    NASA Astrophysics Data System (ADS)

    Aouchiche, N.; Becherif, M.; HadjArab, A.; Aitcheikh, M. S.; Ramadan, H. S.; Cheknane, A.

    2016-10-01

    The power generated by solar photovoltaic (PV) module depends on the surrounding irradiance and temperature. This paper presents a hybrid Matlab™/Pspice™ simulation model of PV system, combined with Cadence software SLPS. The hybridization is performed in order to gain the advantages of both simulation tools such as accuracy and efficiency in both Pspice electronic circuit and Matlab™ mathematical modelling respectively. For this purpose, the PV panel and the boost converter are developed using Pspice™ and hybridized with the mathematical Matlab™ model of maximum power point method controller (MPPT) through SLPS. The main objective is verify the significance of using the proposed hybrid simulation techniques in comparing the different MPPT algorithms such as the perturbation and observation (P&O), incremental of conductance (Inc-Cond) and counter reaction voltage using pilot cell (Pilot-Cell). Various simulations are performed under different atmospheric conditions in order to evaluate the dynamic behaviour for the system under study in terms of stability, efficiency and rapidity.

  11. Study of photovoltaic cost elements. Volume 5: Installation cost model for intermediate PV systems: Users manual

    NASA Astrophysics Data System (ADS)

    Ayers, J. B.

    1981-07-01

    A cost modeling methodology is presented for estimating installation costs associated with intermediate photovoltaic (PV) systems. With only a parametric description of an intermediate power system, the model can be used to develop an installation cost estimate for that system. The model is based on conventional cost-estimating procedures widely used by the construction industry and was validated by comparing estimates for the same 10 systems made independently by a cost engineering firm. A description of the model is included as well as an example of its use with a 200 KW solar breeder plant design to be located in Rockville, Maryland.

  12. Superficial photoluminescence and PV conversion of nanoscale Si-layered systems at 400 nm

    NASA Astrophysics Data System (ADS)

    Kuznicki, Zbigniew T.; Meyrueis, Patrick; Sarrabayrouse, Gérard; Rousset, Bernard

    2006-04-01

    A surprising photovoltaic (PV) conversion at 400 nm has been observed in nanoscale Si-layered systems (ns-Si-ls) during spectral response measurements. In conventional solar cells the UV and blue PV conversion may be poor because of the surface recombination within a thin superficial layer. In multi-interface novel devices (MIND) containing ns-Si-ls this conversion is always negligible within an even thicker surface dead zone from which practically no free-carriers can be collected. So the measured 400 nm band PV conversion in MIND cells is totally inconsistent with usually observed effects. Another CE paradox concerns its inversely proportional variation versus incident flux intensity, lower the intensity higher the CE, which value can even exceed unity. This new effect is also localized at the superficial nanostratum and originates from postimplantation defects and nanostructures formed during the implantation process. A similar low energy free-carrier generation has been observed recently in MIND cells with buried ns-Si-ls having a relatively very thin superficial stratum because of an excellent electronic passivation. No available publication mentions such an effect despite extensive investigations on the subject of structural and optical properties of Si nanoparticles, Si nanolayers, new Si-based materials such as semiconductor silicides and the luminescence-center doped Si materials. In this work, the carrier collection properties of the superficial Si nanostratum are reported and discussed in detail in relation to incident flux intensity. An additional low energy generation was observed experimentally. The effect could have capital importance for a breakthrough in the PV conversion efficiency in Si solar cells with nanotransformations.

  13. Real-time POD-CFD Wind-Load Calculator for PV Systems

    SciTech Connect

    Huayamave, Victor; Divo, Eduardo; Ceballos, Andres; Barriento, Carolina; Stephen, Barkaszi; Hubert, Seigneur

    2014-03-21

    The primary objective of this project is to create an accurate web-based real-time wind-load calculator. This is of paramount importance for (1) the rapid and accurate assessments of the uplift and downforce loads on a PV mounting system, (2) identifying viable solutions from available mounting systems, and therefore helping reduce the cost of mounting hardware and installation. Wind loading calculations for structures are currently performed according to the American Society of Civil Engineers/ Structural Engineering Institute Standard ASCE/SEI 7; the values in this standard were calculated from simplified models that do not necessarily take into account relevant characteristics such as those from full 3D effects, end effects, turbulence generation and dissipation, as well as minor effects derived from shear forces on installation brackets and other accessories. This standard does not include provisions that address the special requirements of rooftop PV systems, and attempts to apply this standard may lead to significant design errors as wind loads are incorrectly estimated. Therefore, an accurate calculator would be of paramount importance for the preliminary assessments of the uplift and downforce loads on a PV mounting system, identifying viable solutions from available mounting systems, and therefore helping reduce the cost of the mounting system and installation. The challenge is that although a full-fledged three-dimensional computational fluid dynamics (CFD) analysis would properly and accurately capture the complete physical effects of air flow over PV systems, it would be impractical for this tool, which is intended to be a real-time web-based calculator. CFD routinely requires enormous computation times to arrive at solutions that can be deemed accurate and grid-independent even in powerful and massively parallel computer platforms. This work is expected not only to accelerate solar deployment nationwide, but also help reach the SunShot Initiative goals

  14. Dynamic Model Validation of PV Inverters Under Short-Circuit Conditions: Preprint

    SciTech Connect

    Muljadi, E.; Singh, M.; Bravo, R.; Gevorgian, V.

    2013-03-01

    Photovoltaic (PV) modules have dramatically decreased in price in the past few years, spurring the expansion of photovoltaic deployment. Residential and commercial rooftop installations are connected to the distribution network; large-scale installation PV power plants (PVPs) have benefited from tax incentives and the low cost of PV modules. As the level penetration of PV generation increases, the impact on power system reliability will also be greater. Utility power system planners must consider the role of PV generation in power systems more realistically by representing PV generation in dynamic stability analyses. Dynamic models of PV inverters have been developed in the positive sequence representation. NREL has developed a PV inverter dynamic model in PSCAD/EMTDC. This paper validates the dynamic model with an actual hardware bench test conducted by Southern California Edison's Distributed Energy Resources laboratory. All the fault combinations -- symmetrical and unsymmetrical -- were performed in the laboratory. We compare the simulation results with the bench test results.

  15. Integration of Behind-the-Meter PV Fleet Forecasts into Utility Grid System Operations

    SciTech Connect

    Hoff, Thomas Hoff; Kankiewicz, Adam

    2016-02-26

    Four major research objectives were completed over the course of this study. Three of the objectives were to evaluate three, new, state-of-the-art solar irradiance forecasting models. The fourth objective was to improve the California Independent System Operator’s (ISO) load forecasts by integrating behind-the-meter (BTM) PV forecasts. The three, new, state-of-the-art solar irradiance forecasting models included: the infrared (IR) satellite-based cloud motion vector (CMV) model; the WRF-SolarCA model and variants; and the Optimized Deep Machine Learning (ODML)-training model. The first two forecasting models targeted known weaknesses in current operational solar forecasts. They were benchmarked against existing operational numerical weather prediction (NWP) forecasts, visible satellite CMV forecasts, and measured PV plant power production. IR CMV, WRF-SolarCA, and ODML-training forecasting models all improved the forecast to a significant degree. Improvements varied depending on time of day, cloudiness index, and geographic location. The fourth objective was to demonstrate that the California ISO’s load forecasts could be improved by integrating BTM PV forecasts. This objective represented the project’s most exciting and applicable gains. Operational BTM forecasts consisting of 200,000+ individual rooftop PV forecasts were delivered into the California ISO’s real-time automated load forecasting (ALFS) environment. They were then evaluated side-by-side with operational load forecasts with no BTM-treatment. Overall, ALFS-BTM day-ahead (DA) forecasts performed better than baseline ALFS forecasts when compared to actual load data. Specifically, ALFS-BTM DA forecasts were observed to have the largest reduction of error during the afternoon on cloudy days. Shorter term 30 minute-ahead ALFS-BTM forecasts were shown to have less error under all sky conditions, especially during the morning time periods when traditional load forecasts often experience their largest

  16. Large scale dynamic systems

    NASA Technical Reports Server (NTRS)

    Doolin, B. F.

    1975-01-01

    Classes of large scale dynamic systems were discussed in the context of modern control theory. Specific examples discussed were in the technical fields of aeronautics, water resources and electric power.

  17. Economic Analysis of a Brackish Water Photovoltaic-Operated (BWRO-PV) Desalination System: Preprint

    SciTech Connect

    Al-Karaghouli, A.; Kazmerski, L. L.

    2010-10-01

    The photovoltaic (PV)-powered reverse-osmosis (RO) desalination system is considered one of the most promising technologies in producing fresh water from both brackish and sea water, especially for small systems located in remote areas. We analyze the economic viability of a small PV-operated RO system with a capacity of 5 m3/day used to desalinate brackish water of 4000 ppm total dissolve solids, which is proposed to be installed in a remote area of the Babylon governorate in the middle of Iraq; this area possesses excellent insolation throughout the year. Our analysis predicts very good economic and environmental benefits of using this system. The lowest cost of fresh water achieved from using this system is US $3.98/ m3, which is very reasonable compared with the water cost reported by small-sized desalination plants installed in rural areas in other parts of the world. Our analysis shows that using this small system will prevent the release annually of 8,170 kg of CO2, 20.2 kg of CO, 2.23 kg of CH, 1.52 kg of particulate matter, 16.41 kg of SO2, and 180 kg of NOx.

  18. Statistical analysis of the performance and simulation of a two-axis tracking PV system

    SciTech Connect

    Perpinan, O.

    2009-11-15

    The energy produced by a photovoltaic system over a given period can be estimated from the incident radiation at the site where the Grid Connected PV System (GCPVS) is located, assuming knowledge of certain basic features of the system under study. Due to the inherently stochastic nature of solar radiation, the question ''How much energy will a GCPVS produce at this location over the next few years?'' involves an exercise of prediction inevitably subjected to a degree of uncertainty. Moreover, during the life cycle of the GCPVS, another question arises: ''Is the system working correctly?''. This paper proposes and examines several methods to cope with these questions. The daily performance of a PV system is simulated. This simulation and the interannual variability of both radiation and productivity are statistically analyzed. From the results several regression adjustments are obtained. This analysis is shown to be useful both for productivity prediction and performance checking exercises. Finally, a statistical analysis of the performance of a GCPVS is carried out as a detection method of malfunctioning parts of the system. (author)

  19. Outdoor PV Degradation Comparison

    SciTech Connect

    Jordan, D. C.; Smith, R. M.; Osterwald, C. R.; Gelak, E.; Kurtz, S. R.

    2011-02-01

    As photovoltaic (PV) penetration of the power grid increases, it becomes vital to know how decreased power output; may affect cost over time. In order to predict power delivery, the decline or degradation rates must be determined; accurately. At the Performance and Energy Rating Testbed (PERT) at the Outdoor Test Facility (OTF) at the; National Renewable Energy Laboratory (NREL) more than 40 modules from more than 10 different manufacturers; were compared for their long-term outdoor stability. Because it can accommodate a large variety of modules in a; limited footprint the PERT system is ideally suited to compare modules side-by-side under the same conditions.

  20. Feasibility Study of Grid Connected PV-Biomass Integrated Energy System in Egypt

    NASA Astrophysics Data System (ADS)

    Barakat, Shimaa; Samy, M. M.; Eteiba, Magdy B.; Wahba, Wael Ismael

    2016-10-01

    The aim of this paper is to present a feasibility study of a grid connected photovoltaic (PV) and biomass Integrated renewable energy (IRE) system providing electricity to rural areas in the Beni Suef governorate, Egypt. The system load of the village is analyzed through the environmental and economic aspects. The model has been designed to provide an optimal system configuration based on daily data for energy availability and demands. A case study area, Monshaet Taher village (29° 1' 17.0718"N, 30° 52' 17.04"E) is identified for economic feasibility in this paper. HOMER optimization model plan imputed from total daily load demand, 2,340 kWh/day for current energy consuming of 223 households with Annual Average Insolation Incident on a Horizontal Surface of 5.79 (kWh/m2/day) and average biomass supplying 25 tons / day. It is found that a grid connected PV-biomass IRE system is an effective way of emissions reduction and it does not increase the investment of the energy system.

  1. Nonlinear phenomenon in monocrystalline silicon based PV module for low power system: Lead acid battery for low energy storage

    NASA Astrophysics Data System (ADS)

    El Amrani, A.; El Amraoui, M.; El Abbassi, A.; Messaoudi, C.

    2014-11-01

    In the present work, we report the indoor photo-electrical measurements of monocrystalline silicon based photovoltaic (PV) module associated with 4 Ah lead acid battery as a storage unit for low power PV system applications. Concerning the PV module, our measurements show, at low illumination regime, that the short circuit current ISC increases linearly with the illumination power levels. Moreover, for high illumination levels, the mechanism of bimolecular recombination and space charge limitation may be intensified and hence the short current of the PV module ISCMod depends sublinearly on the incident optical power; the behavior is nonlinear. For the open circuit voltage of the PV module VOCMod measurements, a linear variation of the VOCMod versus the short circuit current in semi-logarithmic scale has been noticed. The diode ideality factor n and diode saturation current Is have been investigated; the values of n and Is are approximately of 1.3 and 10-9 A, respectively. In addition, we have shown, for different discharging-charging currents rates (i.e. 0.35 A, 0.2 A and 0.04 A), that the battery voltage decreases with discharging time as well as discharging battery capacity, and on the other hand it increases with the charging time and will rise up until it maximized value. The initial result shows the possibility to use such lead acid battery for low power PV system, which is generally designed for the motorcycle battery.

  2. Space Shuttle production verification motor 1 (PV-1) field joint protection system, volume 7

    NASA Technical Reports Server (NTRS)

    Wilkinson, J. P.

    1990-01-01

    The performance of the field joint protection system (FJPS) of the Space Shuttle Production Verification Motor 1 (PV-1), as evaluated by postfire hardware inspection. Compliance with the specifications is shown for the FJPS assembly and components. The simplified FJPS and field joint heaters performed nominally, maintaining all joint seal temperatures within the required range. One anomally was noted on the igniter-to-case joint heater during postfire inspection. The heater buckled off the surface in two areas, resulting in two hot spots on the heater and darkened heater insulation. The condition did not affect heater performance during ignition countdown and all igniter seals were maintained within required temperature limits.

  3. Dynamic load management and optimum sizing of stand-alone hybrid PV/wind system

    NASA Astrophysics Data System (ADS)

    Kaplani, E.; Ntafogiannis, P.; Pappas, K.; Diamantopoulos, N.

    2015-12-01

    Simulation algorithms for the sizing of stand-alone hybrid PV/Wind systems are a powerful tool in evaluating the optimum configuration that would cover the energy demand with a predefined reliability level at the lowest cost. Several parameters such as the interval of the simulation (day, day-night, hourly) and the consumption profile may significantly affect the optimum configuration. This paper examines the effect of these parameters within an optimum sizing simulation algorithm developed. The effect of these parameters was particularly evident at low battery capacities, which involve optimum configurations resulting in minimum cost. Furthermore, shift-able loads in the hourly-based weekly profile assumed in this study were identified, and a dynamic load management functionality was developed. In this approach, loads that could be shifted through time were dynamically allocated during periods of excess energy production by the hybrid PV/Wind system. The results showed an increase in system reliability from 95% to 97% when load shifting was introduced. Finally, sizing the system for only the static (non-shift-able loads) proved to withstand the addition of the extra shift-able loads while retaining the 95% reliability level when the load management functionality was introduced. Thus, a smaller installation with lower cost is achieved.

  4. Quantifying PV power Output Variability

    SciTech Connect

    Hoff, Thomas E.; Perez, Richard

    2010-10-15

    This paper presents a novel approach to rigorously quantify power Output Variability from a fleet of photovoltaic (PV) systems, ranging from a single central station to a set of distributed PV systems. The approach demonstrates that the relative power Output Variability for a fleet of identical PV systems (same size, orientation, and spacing) can be quantified by identifying the number of PV systems and their Dispersion Factor. The Dispersion Factor is a new variable that captures the relationship between PV Fleet configuration, Cloud Transit Speed, and the Time Interval over which variability is evaluated. Results indicate that Relative Output Variability: (1) equals the inverse of the square root of the number of systems for fully dispersed PV systems; and (2) could be further minimized for optimally-spaced PV systems. (author)

  5. Experimental study of a novel photovoltaic solar-assisted heat pump/loop heat-pipe (PV-SAHP/LHP) system

    NASA Astrophysics Data System (ADS)

    Zhang, Tao; Pei, Gang; Zhu, Qunzhi; Ji, Jie

    2017-01-01

    A prototype of a photovoltaic solar-assisted heat-pump/loop heat-pipe system (PV-SAHP/LHP) was constructed in this paper. The system was a combination of photovoltaic solar-assisted heat pump system (PV-SAHP) and loop heat pipe photovoltaic/thermal (LHP-PV/T) system. The combined system can carry out with two modes but using the same working fluid, and the two modes can switch operation freely. R600a was employed as the working fluid, and system performance under different working mode was presented in this paper. The results show that the day average photothermal efficiency & photovoltaic efficiency can reach to 43.6% & 11.3% under LHP-PV/T working mode compared with that of 57.5% & 12.1% under PV-SAHP working mode: Besides that, a day average COP of 3.66 was obtained under PV-SAHP working mode.

  6. CPV Vs. PV from a grid-matching perspective

    NASA Astrophysics Data System (ADS)

    Strobach, E.; Bader, S.; Faiman, D.; Solomon, A. A.; Meron, G.

    2012-10-01

    In a recently-published series of papers we studied the general problem of matching large PV systems of various kinds to the electricity grid. In those studies CPV systems were simulated via an artificial ansatz in which they were treated as 2-axis flat-panel PV systems whose light sensitivity is only to the direct normal component (DNI) of solar irradiance. The present study replaces this ansatz with an experimentally validated model of a real CPV system. We compare a genuine 2-axis high-concentration CPV system with a static flat-panel PV system from the standpoint of matching both system types to the Israeli electricity grid.

  7. Methodology and systems to ensure reliable thin-film PV modules

    NASA Astrophysics Data System (ADS)

    Call, Jon; Varde, Uday; Konson, Alla; Walters, Mike; Kotarba, Chad, III; Kraft, Tim; Guha, Subhendu

    2008-08-01

    The reliability of Uni-Solar triple-junction amorphous silicon thin-film PV modules is very important to their success in an increasingly competitive PV market. Modules must show useful operating lifetimes on the order of 20 to 30 years, and although module efficiency is very important, the total energy a module will produce is largely dependent on its operating lifetime. Thus, it is essential to evaluate module reliability in order to estimate module lifetime and establish customer warranty periods. While real world outdoor exposure testing is necessary and important, it is essential that accelerated environmental test methods are utilized to provide more rapid feedback regarding failure modes, design flaws and degradation mechanisms. The following paper gives an overview of the methodology used to ensure long-term reliability of Uni-Solar flexible thin-film modules. The applied test methods are primarily based upon accepted industry test standards such as IEC-61646, UL-1703, and ASTM. The design, screening, and qualification process to ensure the robustness of new designs is described as well as subsequent module validation testing and manufacturing process control. Test methods important for flexible module laminates are briefly discussed and examples of reliability tests are given. Upon successful design validation and certification, the quality and reliability of manufactured modules is maintained through supplier and product quality assurance programs.

  8. PV_LIB Toolbox

    SciTech Connect

    2012-09-11

    While an organized source of reference information on PV performance modeling is certainly valuable, there is nothing to match the availability of actual examples of modeling algorithms being used in practice. To meet this need, Sandia has developed a PV performance modeling toolbox (PV_LIB) for Matlab. It contains a set of well-documented, open source functions and example scripts showing the functions being used in practical examples. This toolbox is meant to help make the multi-step process of modeling a PV system more transparent and provide the means for model users to validate and understand the models they use and or develop. It is fully integrated into Matlab’s help and documentation utilities. The PV_LIB Toolbox provides more than 30 functions that are sorted into four categories

  9. Remote monitoring of solar PV system for rural areas using GSM, V-F & F-V converters

    NASA Astrophysics Data System (ADS)

    Tejwani, R.; Kumar, G.; Solanki, C. S.

    2016-05-01

    The Small capacity photovoltaic (PV) systems like solar lantern and home lighting systems installed in remote rural area often fail without any prior warning due to lack of monitoring and maintenance. This paper describes implementation of remote monitoring for small capacity solar PV system that uses GSM voice channel for communication. Through GSM analog signal of sine wave with frequency range 300-3500 Hz and amplitude range 2.5-4 V is transmitted. Receiver is designed to work in the same frequency range. The voltage from solar PV system in range of 2 to 7.5 V can be converted to frequency directly at the transmitting end. The frequency range from 300-6000 Hz can be sensed and directly converted to voltage signal at receiving end. Testing of transmission and reception of analog signal through GSM voice channel is done for voltage to frequency (V-F) and frequency to voltage (F-V) conversions.

  10. Large TV display system

    NASA Technical Reports Server (NTRS)

    Liu, Hua-Kuang (Inventor)

    1986-01-01

    A relatively small and low cost system is provided for projecting a large and bright television image onto a screen. A miniature liquid crystal array is driven by video circuitry to produce a pattern of transparencies in the array corresponding to a television image. Light is directed against the rear surface of the array to illuminate it, while a projection lens lies in front of the array to project the image of the array onto a large screen. Grid lines in the liquid crystal array are eliminated by a spacial filter which comprises a negative of the Fourier transform of the grid.

  11. Lanai high-density irradiance sensor network for characterizing solar resource variability of MW-scale PV system.

    SciTech Connect

    Stein, Joshua S.; Johnson, Lars; Ellis, Abraham; Kuszmaul, Scott S.

    2012-01-01

    Sandia National Laboratories (Sandia) and SunPower Corporation (SunPower) have completed design and deployment of an autonomous irradiance monitoring system based on wireless mesh communications and a battery operated data acquisition system. The Lanai High-Density Irradiance Sensor Network is comprised of 24 LI-COR{reg_sign} irradiance sensors (silicon pyranometers) polled by 19 RF Radios. The system was implemented with commercially available hardware and custom developed LabVIEW applications. The network of solar irradiance sensors was installed in January 2010 around the periphery and within the 1.2 MW ac La Ola PV plant on the island of Lanai, Hawaii. Data acquired at 1 second intervals is transmitted over wireless links to be time-stamped and recorded on SunPower data servers at the site for later analysis. The intent is to study power and solar resource data sets to correlate the movement of cloud shadows across the PV array and its effect on power output of the PV plant. The irradiance data sets recorded will be used to study the shape, size and velocity of cloud shadows. This data, along with time-correlated PV array output data, will support the development and validation of a PV performance model that can predict the short-term output characteristics (ramp rates) of PV systems of different sizes and designs. This analysis could also be used by the La Ola system operator to predict power ramp events and support the function of the future battery system. This experience could be used to validate short-term output forecasting methodologies.

  12. Sub-synchronous resonance damping using high penetration PV plant

    NASA Astrophysics Data System (ADS)

    Khayyatzadeh, M.; Kazemzadeh, R.

    2017-02-01

    The growing need to the clean and renewable energy has led to the fast development of transmission voltage-level photovoltaic (PV) plants all over the world. These large scale PV plants are going to be connected to power systems and one of the important subjects that should be investigated is the impact of these plants on the power system stability. Can large scale PV plants help to damp sub-synchronous resonance (SSR) and how? In this paper, this capability of a large scale PV plant is investigated. The IEEE Second Benchmark Model aggregated with a PV plant is utilized as the case study. A Wide Area Measurement System (WAMS) based conventional damping controller is designed and added to the main control loop of PV plant in order to damp the SSR and also investigation of the destructive effect of time delay in remote feedback signal. A new optimization algorithm called teaching-learning-based-optimization (TLBO) algorithm has been used for managing the optimization problems. Fast Furrier Transformer (FFT) analysis and also transient simulations of detailed nonlinear system are considered to investigate the performance of the controller. Robustness of the proposed system has been analyzed by facing the system with disturbances leading to significant changes in generator and power system operating point, fault duration time and PV plant generated power. All the simulations are carried out in MATLAB/SIMULINK environment.

  13. Performance assessment and transient optimization of multi-stage solid desiccant air conditioning systems with building PV/T integration

    NASA Astrophysics Data System (ADS)

    Gadalla, Mohamed; Saghafifar, Mohammad

    2016-09-01

    One of the popular solar air conditioning technologies is desiccant air conditioning. Nonetheless, single stage desiccant air conditioning systems' coefficient of performance (COP) are relatively low. Therefore, multi-stage solid desiccant air conditioning systems are recommended. In this paper, an integrated double-stage desiccant air conditioning systems and PV/T collector is suggested for hot and humid climates such as the UAE. The results for the PV/T implementation in the double-stage desiccant cooling system are assessed against the PV/T results for a single-stage desiccant air conditioning system. In order to provide a valid comparative evaluation between the single and double stage desiccant air conditioning systems, an identical PV/T module, in terms of dimensions, is incorporated into these systems. The overall required auxiliary air heating is abated by 46.0% from 386.8 MWh to 209.0 MWh by replacing the single stage desiccant air conditioning system with the proposed double stage configuration during June to October. Moreover, the overall averaged solar share during the investigated months for the single and double stage systems are 36.5% and 43.3%.

  14. Residential, Commercial, and Utility-Scale Photovoltaic (PV) System Prices in the United States: Current Drivers and Cost-Reduction Opportunities

    SciTech Connect

    Goodrich, A.; James, T.; Woodhouse, M.

    2012-02-01

    The price of photovoltaic (PV) systems in the United States (i.e., the cost to the system owner) has dropped precipitously in recent years, led by substantial reductions in global PV module prices. However, system cost reductions are not necessarily realized or realized in a timely manner by many customers. Many reasons exist for the apparent disconnects between installation costs, component prices, and system prices; most notable is the impact of fair market value considerations on system prices. To guide policy and research and development strategy decisions, it is necessary to develop a granular perspective on the factors that underlie PV system prices and to eliminate subjective pricing parameters. This report's analysis of the overnight capital costs (cash purchase) paid for PV systems attempts to establish an objective methodology that most closely approximates the book value of PV system assets.

  15. Optical Design and Manufacturing of Fresnel Lenses for The First Korean High Concentration Solar PV System

    NASA Astrophysics Data System (ADS)

    Ryu, Kwangsun; Shin, Goo-Hwan; Cha, Wonho; Kang, Seongwon; Kim, Youngsik; Kang, Gi-Hwan

    2011-12-01

    In this study, we designed and optimized flat Fresnel lens and the light pipe to develop 500X concentrated solar PV system. In the process, we compare the transmission efficiencies according to groove types. We performed rigorous ray tracing simulation of the flat Fresnel lenses. The computer aided simulation showed the `grooves in' case has the better efficiency than that of `grooves out' case. Based on the ray-trace results, we designed and manufactured sample Fresnel lenses. The optical performance were measured and compared with ray-trace results. Finally, the optical efficiency was measured to be above 75%. All the design and manufacturing were performed based on that InGaP/InGaAs/Ge triple junction solar cell is used to convert the photon energy to electrical power. Field test will be made and analyzed in the near future.

  16. Locational Sensitivity Investigation on PV Hosting Capacity and Fast Track PV Screening

    SciTech Connect

    Ding, Fei; Mather, Barry; Ainsworth, Nathan; Gotseff, Peter; Baker, Kyri

    2016-05-05

    A 15% PV penetration threshold is commonly used by utilities to define photovoltaic (PV) screening methods where PV penetration is defined as the ratio of total solar PV capacity on a line section to peak load. However, this method doesn't take into account PV locational impact or feeder characteristics that could strongly change the feeder's capability to host PVs. This paper investigates the impact of PV location and phase connection type on PV hosting capacity, and then proposes a fast-track PV screening approach that leverages various PV hosting capacity metric responding to different PV locations and types. The proposed study could help utilities to evaluate PV interconnection requests and also help increase the PV hosting capacity of distribution feeders without adverse impacts on system voltages.

  17. Development of A Fully Integrated PV System for Residential Applications: PVMaT5a Final Report, 18 December 2001

    SciTech Connect

    Oatman, J.; West, R.

    2002-10-01

    This report describes both the Utility Power Group (UPG), a wholly owned subsidiary of Kyocera Solar, Inc., and Xantrex Technology Inc., have designed, assembled, and tested a new photovoltaic (PV) power system for residential rooftops to meet the goal of a readily manufacturable product that will increase US domestic PV power system production and installed capacity, by reducing the total installed cost and increasing the reliability of residential rooftop mounted PV power systems. A new factory pre-fabricated PV array system was developed, and 80 have been installed on the residential rooftops using standard metal parts. The direct material and labor cost of the array installation has been reduced to $3.79 per square foot for a 2400W installation. A modular, maintenance free, battery-based Power Unit and Energy Storage Unit (power conditioning and control) have also been developed. The design, fabrication, and testing have been completed for two prototypes of this system. These products have been evaluated for their structural integrity, electrical performance, reliability, cost, and manufacturability. The direct material and labor cost of the Power Unit has been reduced to $0.34 per watt. The 13 kW-hr Energy Storage Unit (ESU) has been UL listed.

  18. Design, Operation and Economic Analysis of Autonomous Hybrid PV-Diesel Power Systems Including Battery Storage

    NASA Astrophysics Data System (ADS)

    Papadopoulos, Demetrios P.; Maltas, Eleftherios Z.

    2010-01-01

    This paper presents a systematic techno-economic analysis of autonomous PV-Diesel energy system with battery storage. This hybrid type power system was developed and installed on the roof of the Electrical Engineering Laboratory building in the city of Xanthi, Greece, where a weather station is also installed providing necessary meteorological data since 2002. Such system can be generally used to supply electrical loads of isolated remote areas. The actual design of such a system is based on: a pre-defined load pattern to be supplied; the pertinent weather data; the relevant market prices; and the applicable recent economic rates (eg June 2009 for the Greek case). The system is operated on a predictive manner using a Programmable Logic Controller (PLC) which controls the main system parameters for safe and continuous power supply to meet reliably the desired load demand. Three distinct systems of this type and of equal capacity, which combine energy sources and battery storage have been proposed and assessed technically and economically.

  19. Establishment, in silico analysis, and experimental verification of a large-scale metabolic network of the xanthan producing Xanthomonas campestris pv. campestris strain B100.

    PubMed

    Schatschneider, Sarah; Persicke, Marcus; Watt, Steven Alexander; Hublik, Gerd; Pühler, Alfred; Niehaus, Karsten; Vorhölter, Frank-Jörg

    2013-08-20

    The γ-proteobacterium Xanthomonas campestris pv. campestris (Xcc) B100 synthesizes the polysaccharide xanthan, a commercially important viscosifier. Since the complete genome of Xcc B100 is available, systems biology tools were applied to obtain a deeper understanding of the metabolism involved in xanthan biosynthesis. A large-scale metabolic network was reconstructed and manually curated. The reconstructed network included 352 genes, 437 biochemical reactions, 10 transport reactions, and 338 internal metabolites. To use this network for flux balance analysis, the biomass composition of Xcc B100 was determined. The comprehensive model obtained was applied for in silico analyses to predict biomass generation and gene essentiality. Predictions were extensively validated by analyzing batch culture performance and by carbon balancing including xanthan production. Single gene deletion mutants causing deficiencies in the central carbohydrate metabolism were constructed to enforce major flux redistributions. The impact of xanthan production was studied in vivo and in silico, comparing the physiology of a gumD mutant, negative in xanthan production, with the original strain. The results indicate a redistribution of resources from xanthan to biomass, rather than a reduction in carbon uptake. With this high quality metabolic model, both systems biology analyses and synthetic biology reengineering of Xcc gained an important tool.

  20. Comparison of Pyranometers vs. PV Reference Cells for Evaluation of PV Array Performance

    SciTech Connect

    Dunn, L.; Gostein, M.; Emery, K.

    2012-09-01

    As the photovoltaics (PV) industry has grown, the need for accurately monitoring the solar resource of PV power plants has increased. Historically, the PV industry has relied on thermopile pyranometers for irradiance measurements, and a large body of historical irradiance data taken with pyranometers exists. However, interest in PV reference devices is increasing. In this paper, we discuss why PV reference devices are better suited for PV applications, and estimate the typical uncertainties in irradiance measurements made with both pyranometers and PV reference devices. We assert that the quantity of interest in monitoring a PV power plant is the equivalent irradiance under the IEC 60904-3 reference solar spectrum that would produce the same electrical response in the PV array as the incident solar radiation. For PV-plant monitoring applications, we find the uncertainties in irradiance measurements of this type to be on the order of +/-5% for thermopile pyranometers and +/-2.4% for PV reference devices.

  1. Advanced polymer PV system: PVMaT 4A1 annual report, September 1995--September 1996

    SciTech Connect

    Hanoka, J; Chleboski, R; Farber, M; Fava, J; Kane, P; Martz, J

    1997-06-01

    Purpose of this subcontract was to produce lower module and systems costs through the innovative use of polymeric materials. The Innovative Mounting System (IMS) was developed and testing begun during the first year of this contract. IMS reduces the cost of installed PV systems by reducing labor and materials costs both in the factory and in field installation. It incorporates several advances in polymers, processing methods and product design. An advanced backskin material permits elimination of the conventional Al perimeter frame by protecting and sealing the edge and by direct bonding of multifunctional mounting bars. Electrical interconnection is easier and more reliable with a new junction box. Feasibility of a non-vacuum, high-throughput lamination method was also demonstrated, involving a novel transparent encapsulant with UV stabilization package that can be laminated in air and which should lead to longer field life than conventional designs. The first-year program culminated in the fielding of prototype products with the new encapsulant, backskin, junction box, frameless edge seal, and IMS. Feedback and marketing information from potential customers were solicited. Result promises a $0.50/watt manufacturing and system cost reductions as well as increased system lifetime. The second year will complete refinement and test of the encapsulant and backskin, complete the new lamination method, and refine product designs.

  2. Genome-scale mutagenesis and phenotypic characterization of two-component signal transduction systems in Xanthomonas campestris pv. campestris ATCC 33913.

    PubMed

    Qian, Wei; Han, Zhong-Ji; Tao, Jun; He, Chaozu

    2008-08-01

    The gram-negative bacterium Xanthomonas campestris pv. campestris is the causal agent of black rot disease of cruciferous plants. Its genome encodes a large repertoire of two-component signal transduction systems (TCSTSs), which consist of histidine kinases and response regulators (RR) to monitor and respond to environmental stimuli. To investigate the biological functions of these TCSTS genes, we aimed to inactivate all 54 RR genes in X. campestris pv. campestris ATCC 33913, and successfully generated 51 viable mutants using the insertion inactivation method. Plant inoculation identified two novel response regulator genes (XCC1958 and XCC3107) that are involved in virulence of this strain. Genetic complementation demonstrated that XCC3107, designated as vgrR (virulence and growth regulator), also affects bacterial growth and activity of extracellular proteases. In addition, we assessed the survival of these mutants under various stresses, including osmotic stress, high sodium concentration, heat shock, and sodium dodecyl sulfate exposure, and identified a number of genes that may be involved in the general stress response of X. campestris pv. campestris. Mutagenesis and phenotypic characterization of RR genes in this study will facilitate future studies on signaling networks in this important phytopathogenic bacterium.

  3. Design construction and analysis of solar ridge concentrator photovoltaic (PV) system to improve battery charging performance.

    PubMed

    Narasimman, Kalaiselvan; Selvarasan, Iniyan

    2016-05-01

    A ridge concentrator photovoltaic system for a 10W multi-crystalline solar panel was designed with the concentration ratios of 1X and 2X. The ray tracing model of ridge concentrator photovoltaic system was carried out using Trace-Pro simulation. The optimum tilt angle for the concentrator PV system throughout the year was computed. The electrical parameters of the 3 panels were analyzed. The effect of temperature on the electrical performance of the panel was also studied. The reduction of voltage due to increasing panel temperature was managed by MPES type Charge controller. Glass reflector with reflectivity 0.95 was chosen as the ridge wall for the concentrator system. The maximum power outputs for the 1X and 2X panel reached were 9W and 10.5W with glass reflector. The percentage of power improvement for 1X and 2X concentrations were 22.3% and 45.8% respectively. The 2X concentrated panel connected battery takes lower time to charge compared with normal panel connected battery. Copyright © 2016. Published by Elsevier Inc.

  4. Selective harmonic elimination strategy in eleven level inverter for PV system with unbalanced DC sources

    NASA Astrophysics Data System (ADS)

    Ghoudelbourk, Sihem.; Dib, D.; Meghni, B.; Zouli, M.

    2017-02-01

    The paper deals with the multilevel converters control strategy for photovoltaic system integrated in distribution grids. The objective of the proposed work is to design multilevel inverters for solar energy applications so as to reduce the Total Harmonic Distortion (THD) and to improve the power quality. The multilevel inverter power structure plays a vital role in every aspect of the power system. It is easier to produce a high-power, high-voltage inverter with the multilevel structure. The topologies of multilevel inverter have several advantages such as high output voltage, lower total harmonic distortion (THD) and reduction of voltage ratings of the power semiconductor switching devices. The proposed control strategy ensures an implementation of selective harmonic elimination (SHE) modulation for eleven levels. SHE is a very important and efficient strategy of eliminating selected harmonics by judicious selection of the firing angles of the inverter. Harmonics elimination technique eliminates the need of the expensive low pass filters in the system. Previous research considered that constant and equal DC sources with invariant behavior; however, this research extends earlier work to include variant DC sources, which are typical of lead-acid batteries when used in system PV. This Study also investigates methods to minimize the total harmonic distortion of the synthesized multilevel waveform and to help balance the battery voltage. The harmonic elimination method was used to eliminate selected lower dominant harmonics resulting from the inverter switching action.

  5. [Detection system for Xanthomonas axonopodis pv. citri using rolling circle amplification].

    PubMed

    Huang, Guanjun; Yin, Youping; Zhang, Lun; Li, Xiaojiao; Ge, Jianjun; Chen, Hongjun; Wang, Zhongkang

    2008-03-01

    Padlock probe was designed based on the sequence of the unique hypothetic protein gene in complete genome of Xanthomonas axonopodis pv. citri (Xac), and amplification primers ware designed according to the universal linking sequence of padlock probe. Detection system of rolling circle amplification (RCA) was established and optimized. Results show that the system could detect Xac and its DNA specifically, while other plant pathogens and bacteria attached on the surface of citrus leaves could not be detected. This indicates that the detection system had its specificity. The detection sensitivity of RCA was 20 cfu/microL for Xac cells and 10(2) copy/microL for cloned DNA fragment, which was slightly higher than the sensitivity of conventional PCR. Leaf samples collected from orange orchards were detected with both RCA and conventional PCR. The result shows that the Xac positive percentage had no remarkable difference between the two methods (P>0.01). Because the universal linking sequence in padlock probe can use same amplification condition, the new technology and detection system can be used to detect diverse plant pathogens simultaneously in plant quarantine and disease pre-symptom diagnosis.

  6. DOE High Performance Concentrator PV Project

    SciTech Connect

    McConnell, R.; Symko-Davies, M.

    2005-08-01

    Much in demand are next-generation photovoltaic (PV) technologies that can be used economically to make a large-scale impact on world electricity production. The U.S. Department of Energy (DOE) initiated the High-Performance Photovoltaic (HiPerf PV) Project to substantially increase the viability of PV for cost-competitive applications so that PV can contribute significantly to both our energy supply and environment. To accomplish such results, the National Center for Photovoltaics (NCPV) directs in-house and subcontracted research in high-performance polycrystalline thin-film and multijunction concentrator devices with the goal of enabling progress of high-efficiency technologies toward commercial-prototype products. We will describe the details of the subcontractor and in-house progress in exploring and accelerating pathways of III-V multijunction concentrator solar cells and systems toward their long-term goals. By 2020, we anticipate that this project will have demonstrated 33% system efficiency and a system price of $1.00/Wp for concentrator PV systems using III-V multijunction solar cells with efficiencies over 41%.

  7. Plant flavonoids target Pseudomonas syringae pv. tomato DC3000 flagella and type III secretion system.

    PubMed

    Vargas, Paola; Farias, Gabriela A; Nogales, Joaquina; Prada, Harold; Carvajal, Vivian; Barón, Matilde; Rivilla, Rafael; Martín, Marta; Olmedilla, Adela; Gallegos, María-Trinidad

    2013-12-01

    Flavonoids are among the most abundant plant secondary metabolites involved in plant protection against pathogens, but micro-organisms have developed resistance mechanisms to those compounds. We previously demonstrated that the MexAB-OprM efflux pump mediates resistance of Pseudomonas syringae pv. tomato (Pto) DC3000 to flavonoids, facilitating its survival and the colonization of the host. Here, we have shown that tomato plants respond to Pto infection producing flavonoids and other phenolic compounds. The effects of flavonoids on key traits of this model plant-pathogen bacterium have also been investigated observing that they reduce Pto swimming and swarming because of the loss of flagella, and also inhibited the expression and assembly of a functional type III secretion system. Those effects were more severe in a mutant lacking the MexAB-OprM pump. Our results suggest that flavonoids inhibit the function of the GacS/GacA two-component system, causing a depletion of rsmY RNA, therefore affecting the synthesis of two important virulence factors in Pto DC3000, flagella and the type III secretion system. These data provide new insights into the flavonoid role in the molecular dialog between host and pathogen.

  8. Grid-Competitive Residential and Commercial Fully Automated PV Systems Technology: Final technical Report, August 2011

    SciTech Connect

    Brown, Katie E.; Cousins, Peter; Culligan, Matt; Jonathan Botkin; DeGraaff, David; Bunea, Gabriella; Rose, Douglas; Bourne, Ben; Koehler, Oliver

    2011-08-26

    Under DOE's Technology Pathway Partnership program, SunPower Corporation developed turn-key, high-efficiency residential and commercial systems that are cost effective. Key program objectives include a reduction in LCOE values to 9-12 cents/kWh and 13-18 cents/kWh respectively for the commercial and residential markets. Target LCOE values for the commercial ground, commercial roof, and residential markets are 10, 11, and 13 cents/kWh. For this effort, SunPower collaborated with a variety of suppliers and partners to complete the tasks below. Subcontractors included: Solaicx, SiGen, Ribbon Technology, Dow Corning, Xantrex, Tigo Energy, and Solar Bridge. SunPower's TPP addressed nearly the complete PV value chain: from ingot growth through system deployment. Throughout the award period of performance, SunPower has made progress toward achieving these reduced costs through the development of 20%+ efficient modules, increased cell efficiency through the understanding of loss mechanisms and improved manufacturing technologies, novel module development, automated design tools and techniques, and reduced system development and installation time. Based on an LCOE assessment using NREL's Solar Advisor Model, SunPower achieved the 2010 target range, as well as progress toward 2015 targets.

  9. System Voltage Potential-Induced Degradation Mechanisms in PV Modules and Methods for Test

    SciTech Connect

    Hacke, P.; Terwilliger, K.; Smith, R.; Glick, S.; Pankow, J.; Kempe, M.; Kurtz, S.; Bennett, I.; Kloos, M.

    2011-01-01

    Over the past decade, degradation and power loss have been observed in PV modules resulting from the stress exerted by system voltage bias. This is due in part to qualification tests and standards that do not adequately evaluate for the durability of modules to the long-term effects of high voltage bias experienced in fielded arrays. High voltage can lead to module degradation by multiple mechanisms. The extent of the voltage bias degradation is linked to the leakage current or culombs passed from the silicon active layer through the encapsulant and glass to the grounded module frame, which can be experimentally determined; however, competing processes make the effect non-linear and history-dependent. Appropriate testing methods and stress levels are described that demonstrate module durability to system voltage potential-induced degradation (PID) mechanisms. This information, along with outdoor testing that is in progress, is used to estimate the acceleration factors needed to evaluate the durability of modules to system voltage stress. Na-rich precipitates are observed on the cell surface after stressing the module to induce PID in damp heat with negative bias applied to the active layer.

  10. System Voltage Potential-Induced Degradation Mechanisms in PV Modules and Methods for Test: Preprint

    SciTech Connect

    Hacke, P.; Terwilliger, K.; Smith, R.; Glick, S.; Pankow, J.; Kempe, M.; Kurtz, S.; Bennett, I.; Kloos, M.

    2011-07-01

    Over the past decade, degradation and power loss have been observed in PV modules resulting from the stress exerted by system voltage bias. This is due in part to qualification tests and standards that do not adequately evaluate for the durability of modules to the long-term effects of high voltage bias experienced in fielded arrays. High voltage can lead to module degradation by multiple mechanisms. The extent of the voltage bias degradation is linked to the leakage current or coulombs passed from the silicon active layer through the encapsulant and glass to the grounded module frame, which can be experimentally determined; however, competing processes make the effect non-linear and history-dependent. Appropriate testing methods and stress levels are described that demonstrate module durability to system voltage potential-induced degradation (PID) mechanisms. This information, along with outdoor testing that is in progress, is used to estimate the acceleration factors needed to evaluate the durability of modules to system voltage stress. Na-rich precipitates are observed on the cell surface after stressing the module to induce PID in damp heat with negative bias applied to the active layer.

  11. Dual-purpose self-deliverable lunar surface PV electrical power system

    NASA Technical Reports Server (NTRS)

    Arnold, Jack H.; Harris, David W.; Cross, Eldon R.; Flood, Dennis J.

    1991-01-01

    A safe haven and work supported PV power systems on the lunar surface will likely be required by NASA in support of the manned outpost scheduled for the post-2000 lunar/Mars exploration and colonization initiative. Initial system modeling and computer analysis shows that the concept is workable and contains no major high risk technology issues which cannot be resolved in the circa 2000 to 2025 timeframe. A specific selection of the best suited type of electric thruster has not been done; the initial modeling was done using an ion thruster, but Rocketdyne must also evaluate arc and resisto-jets before a final design can be formulated. As a general observation, it appears that such a system can deliver itself to the Moon using many system elements that must be transported as dead payload mass in more conventional delivery modes. It further appears that a larger power system providing a much higher safe haven power level is feasible if this delivery system is implemented, perhaps even sufficient to permit resource prospecting and/or lab experimentation. The concept permits growth and can be expanded to include cargo transport such as habitat and working modules. In short, the combined payload could be manned soon after landing and checkout. NASA has expended substantial resources in the development of electric propulsion concepts and hardware that can be applied to a lunar transport system such as described herein. In short, the paper may represent a viable mission on which previous investments play an invaluable role. A more comprehensive technical paper which embodies second generation analysis and system size will be prepared for near-term presentation.

  12. Exploring the Economic Value of EPAct 2005's PV Tax Credits

    SciTech Connect

    Bolinger, Mark A; Wiser, Ryan; Ing, Edwin

    2009-08-01

    This CESA - LBNL Case Study examines how much economic value do new and expanded federal tax credits really provide to PV system purchasers, and what implications might they hold for state/utility PV grant programs. The report begins with a discussion of the taxability of PV grants and their interaction with federal credits, as this issue significantly affects the analysis that follows. We then calculate the incremental value of EPAct's new and expanded credits for PV systems of different sizes, and owned by different types of entities. The report concludes with a discussion of potential implications for purchasers of PV systems, as well as for administrators of state/utility PV programs. The market for grid-connected photovoltaics (PV) in the US has grown dramatically in recent years, driven in large part by PV grant or 'buy-down' programs in California, New Jersey, and many other states. The recent announcement of a new 11-year, $3.2 billion PV program in California suggests that state policy will continue to drive even faster growth over the next decade. Federal policy has also played a role, primarily by providing commercial PV systems access to tax benefits, including accelerated depreciation (5-year MACRS schedule) and a business energy investment tax credit (ITC). Since the signing of the Energy Policy Act of 2005 (EPAct) on August 8, the federal government has begun to play a much more significant role in supporting both commercial and residential PV systems. Specifically, EPAct increased the federal ITC for commercial PV systems from 10% to 30% of system costs, and also created a new 30% ITC (capped at $2000) for residential solar systems. Both changes went into effect on January 1, 2006, for an initial period of two years, and in late 2006 were extended for an additional year. Unless extended further, the new residential ITC will expire, and the 30% commercial ITC will revert back to 10%, on January 1, 2009. How much economic value do these new and

  13. U.S. Residential Photovoltaic (PV) System Prices, Q4 2013 Benchmarks: Cash Purchase, Fair Market Value, and Prepaid Lease Transaction Prices

    SciTech Connect

    Davidson, C.; James, T. L.; Margolis, R.; Fu, R.; Feldman, D.

    2014-10-01

    The price of photovoltaic (PV) systems in the United States (i.e., the cost to the system owner) has dropped precipitously in recent years, led by substantial reductions in global PV module prices. This report provides a Q4 2013 update for residential PV systems, based on an objective methodology that closely approximates the book value of a PV system. Several cases are benchmarked to represent common variation in business models, labor rates, and module choice. We estimate a weighted-average cash purchase price of $3.29/W for modeled standard-efficiency, polycrystalline-silicon residential PV systems installed in the United States. This is a 46% decline from the 2013-dollar-adjusted price reported in the Q4 2010 benchmark report. In addition, this report frames the cash purchase price in the context of key price metrics relevant to the continually evolving landscape of third-party-owned PV systems by benchmarking the minimum sustainable lease price and the fair market value of residential PV systems.

  14. Examining System-Wide Impacts of Solar PV Control Systems with a Power Hardware-in-the-Loop Platform

    SciTech Connect

    Williams, Tess L.; Fuller, Jason C.; Schneider, Kevin P.; Palmintier, Bryan; Lundstrom, Blake; Chakraborty, Sudipta

    2014-10-11

    High penetration levels of distributed solar PV power generation can lead to adverse power quality impacts such as excessive voltage rise, voltage flicker, and reactive power values that result in unacceptable voltage levels. Advanced inverter control schemes have been proposed that have the potential to mitigate many power quality concerns. However, closed-loop control may lead to unintended behavior in deployed systems as complex interactions can occur between numerous operating devices. In order to enable the study of the performance of advanced control schemes in a detailed distribution system environment, a Hardware-in-the-Loop (HIL) platform has been developed. In the HIL system, GridLAB-D, a distribution system simulation tool, runs in real-time mode at the Pacific Northwest National Laboratory (PNNL) and supplies power system parameters at a point of common coupling to hardware located at the National Renewable Energy Laboratory (NREL). Hardware inverters interact with grid and PV simulators emulating an operational distribution system and power output from the inverters is measured and sent to PNNL to update the real-time distribution system simulation. The platform is described and initial test cases are presented. The platform is used to study the system-wide impacts and the interactions of controls applied to inverters that are integrated into a simulation of the IEEE 8500-node test feeder, with inverters in either constant power factor control or active volt/VAR control. We demonstrate that this HIL platform is well-suited to the study of advanced inverter controls and their impacts on the power quality of a distribution feeder. Additionally, the results from HIL are used to validate GridLAB-D simulations of advanced inverter controls.

  15. Examining System-Wide Impacts of Solar PV Control Systems with a Power Hardware-in-the-Loop Platform

    SciTech Connect

    Williams, Tess L.; Fuller, Jason C.; Schneider, Kevin P.; Palmintier, Bryan; Lundstrom, Blake; Chakraborty, Sudipta

    2014-06-08

    High penetration levels of distributed solar PV power generation can lead to adverse power quality impacts, such as excessive voltage rise, voltage flicker, and reactive power values that result in unacceptable voltage levels. Advanced inverter control schemes have been developed that have the potential to mitigate many power quality concerns. However, local closed-loop control may lead to unintended behavior in deployed systems as complex interactions can occur between numerous operating devices. To enable the study of the performance of advanced control schemes in a detailed distribution system environment, a test platform has been developed that integrates Power Hardware-in-the-Loop (PHIL) with concurrent time-series electric distribution system simulation. In the test platform, GridLAB-D, a distribution system simulation tool, runs a detailed simulation of a distribution feeder in real-time mode at the Pacific Northwest National Laboratory (PNNL) and supplies power system parameters at a point of common coupling. At the National Renewable Energy Laboratory (NREL), a hardware inverter interacts with grid and PV simulators emulating an operational distribution system. Power output from the inverters is measured and sent to PNNL to update the real-time distribution system simulation. The platform is described and initial test cases are presented. The platform is used to study the system-wide impacts and the interactions of inverter control modes—constant power factor and active Volt/VAr control—when integrated into a simulated IEEE 8500-node test feeder. We demonstrate that this platform is well-suited to the study of advanced inverter controls and their impacts on the power quality of a distribution feeder. Additionally, results are used to validate GridLAB-D simulations of advanced inverter controls.

  16. PV water pumping: NEOS Corporation recent PV water pumping activities

    SciTech Connect

    Lane, C.

    1995-11-01

    NEOS Corporation has been very active in PV-powered water pumping, particularly with respect to electric utilities. Most of the recent activity has been through the Photovoltaic Services Network (PSN). The PSN is an independent, not-for-profit organization comprised of all types of electric utilities: rural electric coops, public power districts, investor-owned utilities, and power marketing agencies. The PSN`s mission is to work pro-actively to promote utility involvement in PV through education and training. PV information is distributed by the PSN in three primary forms: (1) consultation with PSN technical service representatives: (2) literature generated by the PSN; and (3) literature published by other organizations. The PSN can also provide assistance to members in developing PV customer service programs. The PSN`s product support activities include consolidation of information on existing packaged PV systems and facilitation of the development of new PV product packages that meet utility-defined specifications for cost performance, and reliability. The PSN`s initial product support efforts will be focused on commercially available packaged PV systems for a variety of off-grid applications. In parallel with this effort, if no products exist that meet the PSN`s functional specifications, the PSN will initiate the second phase of product development support process by encouraging the development of new packaged systems. Through these services and product support activities, the PSN anticipates engaging all segments for the PV industry, thus providing benefits to PV systems suppliers as well as local PV service contractors.This paper describes field testing of pv power systems for water pumping.

  17. Coordination of International Standards with Implementation of the IECRE Conformity Assessment System to Provide Multiple Certification Offerings for PV Power Plants

    SciTech Connect

    Kelly, George; Haring, Adrian; Spooner, Ted; Ball, Greg; Kurtz, Sarah; Heinze, Matthias; Yamamichi, Masaaki; Eguchi, Yoshihito; Ramu, Govind

    2016-11-21

    To help address the industry's needs for assuring the value and reducing the risk of investments in PV power plants; the International Electrotechnical Commission (IEC) has established a new conformity assessment system for renewable energy (IECRE). There are presently important efforts underway to define the requirements for various types of PV system certificates, and publication of the international standards upon which these certifications will be based. This paper presents a detailed analysis of the interrelationship of these activities and the timing for initiation of IECRE PV system certifications.

  18. Impact of distributed power electronics on the lifetime and reliability of PV systems: Impact of distributed power electronics

    DOE PAGES

    Olalla, Carlos; Maksimovic, Dragan; Deline, Chris; ...

    2017-04-26

    Here, this paper quantifies the impact of distributed power electronics in photovoltaic (PV) systems in terms of end-of-life energy-capture performance and reliability. The analysis is based on simulations of PV installations over system lifetime at various degradation rates. It is shown how module-level or submodule-level power converters can mitigate variations in cell degradation over time, effectively increasing the system lifespan by 5-10 years compared with the nominal 25-year lifetime. An important aspect typically overlooked when characterizing such improvements is the reliability of distributed power electronics, as power converter failures may not only diminish energy yield improvements but also adversely affectmore » the overall system operation. Failure models are developed, and power electronics reliability is taken into account in this work, in order to provide a more comprehensive view of the opportunities and limitations offered by distributed power electronics in PV systems. Lastly, it is shown how a differential power-processing approach achieves the best mismatch mitigation performance and the least susceptibility to converter faults.« less

  19. Ota City : characterizing output variability from 553 homes with residential PV systems on a distribution feeder.

    SciTech Connect

    Stein, Joshua S.; Miyamoto, Yusuke; Nakashima, Eichi; Lave, Matthew

    2011-11-01

    This report describes in-depth analysis of photovoltaic (PV) output variability in a high-penetration residential PV installation in the Pal Town neighborhood of Ota City, Japan. Pal Town is a unique test bed of high-penetration PV deployment. A total of 553 homes (approximately 80% of the neighborhood) have grid-connected PV totaling over 2 MW, and all are on a common distribution line. Power output at each house and irradiance at several locations were measured once per second in 2006 and 2007. Analysis of the Ota City data allowed for detailed characterization of distributed PV output variability and a better understanding of how variability scales spatially and temporally. For a highly variable test day, extreme power ramp rates (defined as the 99th percentile) were found to initially decrease with an increase in the number of houses at all timescales, but the reduction became negligible after a certain number of houses. Wavelet analysis resolved the variability reduction due to geographic diversity at various timescales, and the effect of geographic smoothing was found to be much more significant at shorter timescales.

  20. Gac two-component system in Pseudomonas syringae pv. tabaci is required for virulence but not for hypersensitive reaction.

    PubMed

    Marutani, Mizuri; Taguchi, Fumiko; Ogawa, Yujiro; Hossain, Md Mijan; Inagaki, Yoshishige; Toyoda, Kazuhiro; Shiraishi, Tomonori; Ichinose, Yuki

    2008-04-01

    Pseudomonas syringae pv. tabaci 6605 causes wildfire disease on host tobacco plants. To investigate the regulatory mechanism of the expression of virulence, Gac two-component system-defective mutants, DeltagacA and DeltagacS, and a double mutant, DeltagacADeltagacS, were generated. These mutants produced smaller amounts of N-acyl homoserine lactones required for quorum sensing, had lost swarming motility, and had reduced expression of virulence-related hrp genes and the algT gene required for exopolysaccharide production. The ability of the mutants to cause disease symptoms in their host tobacco plant was remarkably reduced, while they retained the ability to induce hypersensitive reaction (HR) in the nonhost plants. These results indicated that the Gac two-component system of P. syringae pv. tabaci 6605 is indispensable for virulence on the host plant, but not for HR induction in the nonhost plants.

  1. Integrating High Penetrations of PV into Southern California

    SciTech Connect

    Kroposki, B.; Mather, B.; Hasper-Tuttle, J.; Neal, R.; Katiraei, F.; Yazdani, A.; Aguero, J. R.; Hoff, T. E.; Norris, B. L.; Parkins, A.; Seguin, R.; Schauder, C.

    2011-01-01

    California regulators recently approved a plan proposed by Southern California Edison (SCE) to install 500 MW of distributed photovoltaic (PV) energy in its utility service territory over the next 5 years. The installations will include 250 MW of utility-owned solar and 250 MW of independently owned solar. SCE expects that the majority of these systems will be commercial-scale rooftop PV systems connected at various points in the distribution system. Each of the SCE rooftop PV systems will typically have a rating of 1-3 MW. To understand the impact of high-penetration PV on the distribution grid, the National Renewable Energy Laboratory (NREL) and SCE brought together a team of experts in resource assessment, distribution modeling, and planning to help analyze the impacts of adding high penetration of PV into the distribution system. Through modeling and simulation, laboratory testing, and field demonstrations, the team will address the issues identified in the analysis by fully examining the challenges, developing solutions, and transitioning those solutions to the field for large-scale deployment. This paper gives an update on the project and discusses technical results of integrating a large number of distributed PV systems into the grid.

  2. Economic and Environmental Assessment of a 1 MW Grid Connected Rooftop Solar PV System for Energy Efficient Building in Bangladesh

    NASA Astrophysics Data System (ADS)

    Chakraborty, Sanjib; Hosain, Rubayet; Rahman, Toufiqur; Rabbi, Ahmead Fazle

    This paper evaluates the potentiality of a 1 MW grid connected rooftop solar PV system for an Energy Efficient Building in Bangladesh, which was estimated by utilizing NASA SSE solar radiation data, PVsyst simulation software and RETScreen simulation software. Economic and environmental viability for a ten-storied building with roof area of 6,500 m2 in the Capital City of Bangladesh, Dhaka was assessed by using the RETScreen simulation software. The yearly electricity production of the proposed system was 1,581 MWh estimated by PVsyst where the technical prospective of gird-connected solar PV in Bangladesh was calculated as about 50,174 MW. The economic assessments were determined the simple payback in such a way that the generated electricity first fulfills the demand of the building, and then the rest of the energy is supplied to the grid. The result indicates that the roof top solar PV system for an Energy efficient building in Dhaka city has a favorable condition for development both in economic and environmental point of view.

  3. A Framework for Evaluating Economic Impacts of Rooftop PV Systems with or without Energy Storage on Thai Distribution Utilities and Ratepayers

    NASA Astrophysics Data System (ADS)

    Chaianong, A.; Bangviwat, A.; Menke, C.

    2017-07-01

    Driven by decreasing PV and energy storage prices, increasing electricity costs and policy supports from Thai government (self-consumption era), rooftop PV and energy storage systems are going to be deployed in the country rapidly that may disrupt existing business models structure of Thai distribution utilities due to revenue erosion and lost earnings opportunities. The retail rates that directly affect ratepayers (non-solar customers) are expected to increase. This paper focuses on a framework for evaluating impacts of PV with and without energy storage systems on Thai distribution utilities and ratepayers by using cost-benefit analysis (CBA). Prior to calculation of cost/benefit components, changes in energy sales need to be addressed. Government policies for the support of PV generation will also help in accelerating the rooftop PV installation. Benefit components include avoided costs due to transmission losses and deferring distribution capacity with appropriate PV penetration level, while cost components consist of losses in revenue, program costs, integration costs and unrecovered fixed costs. It is necessary for Thailand to compare total costs and total benefits of rooftop PV and energy storage systems in order to adopt policy supports and mitigation approaches, such as business model innovation and regulatory reform, effectively.

  4. Benchmarking of Typical Meteorological Year datasets dedicated to Concentrated-PV systems

    NASA Astrophysics Data System (ADS)

    Realpe, Ana Maria; Vernay, Christophe; Pitaval, Sébastien; Blanc, Philippe; Wald, Lucien; Lenoir, Camille

    2016-04-01

    Accurate analysis of meteorological and pyranometric data for long-term analysis is the basis of decision-making for banks and investors, regarding solar energy conversion systems. This has led to the development of methodologies for the generation of Typical Meteorological Years (TMY) datasets. The most used method for solar energy conversion systems was proposed in 1978 by the Sandia Laboratory (Hall et al., 1978) considering a specific weighted combination of different meteorological variables with notably global, diffuse horizontal and direct normal irradiances, air temperature, wind speed, relative humidity. In 2012, a new approach was proposed in the framework of the European project FP7 ENDORSE. It introduced the concept of "driver" that is defined by the user as an explicit function of the pyranometric and meteorological relevant variables to improve the representativeness of the TMY datasets with respect the specific solar energy conversion system of interest. The present study aims at comparing and benchmarking different TMY datasets considering a specific Concentrated-PV (CPV) system as the solar energy conversion system of interest. Using long-term (15+ years) time-series of high quality meteorological and pyranometric ground measurements, three types of TMY datasets generated by the following methods: the Sandia method, a simplified driver with DNI as the only representative variable and a more sophisticated driver. The latter takes into account the sensitivities of the CPV system with respect to the spectral distribution of the solar irradiance and wind speed. Different TMY datasets from the three methods have been generated considering different numbers of years in the historical dataset, ranging from 5 to 15 years. The comparisons and benchmarking of these TMY datasets are conducted considering the long-term time series of simulated CPV electric production as a reference. The results of this benchmarking clearly show that the Sandia method is not

  5. An ice nucleation reporter gene system: identification of inducible pathogenicity genes in Pseudomonas syringae pv. phaseolicola.

    PubMed Central

    Lindgren, P B; Frederick, R; Govindarajan, A G; Panopoulos, N J; Staskawicz, B J; Lindow, S E

    1989-01-01

    We have constructed derivatives of the transposon Tn3 that allow an ice nucleation gene (inaZ) to be used as 'reporter' of the transcriptional activity of genes into which it is inserted. In these derivatives (Tn3-Ice and Tn3-Spice), the lacZYA sequences of transposon Tn3-HoHo1 were replaced with inaZ lacking its native promoter. The ice nucleation activity of virB::inaZ fusions in the correct transcriptional orientation was inducible by acetosyringone, a plant metabolite which activates the vir operon of Agrobacterium tumefaciens Ti plasmids, while fusions in the opposite orientation were unresponsive to the inducer. Tn3-Spice was also used to investigate the expression of a cluster of genes (hrp) which control pathogenicity and hypersensitivity elicited by Pseudomonas syringae pv. phaseolicola. An inducible region was identified which is expressed at low levels in vitro but becomes activated when the bacteria come into contact with the susceptible host, bean. Activation of this region occurred within 2 h post-inoculation and was nearly complete by the time the bacteria began to multiply in the leaf tissue. The inaZ reporter appears to be at least 10(5)-fold more sensitive than lacZ in P.s.phaseolicola. Thus, the inaZ fusion system provides a sensitive, convenient and inexpensive tool for the study of bacterial gene expression, particularly during plant pathogenesis, and should be generally useful as a reporter gene system in Gram-negative bacteria. PMID:2548841

  6. Tilt to horizontal global solar irradiance conversion: application to PV systems data

    NASA Astrophysics Data System (ADS)

    Housmans, Caroline; Leloux, Jonathan; Bertrand, Cédric

    2017-04-01

    Many transposition models have been proposed in the literature to convert solar irradiance on the horizontal plane to that on a tilted plane requiring that at least two of the three solar components (i.e. global, direct and diffuse) are known. When only global irradiance measurements are available, the conversion from horizontal to tilted planes is still possible but in this case transposition models have to be coupled with decomposition models (i.e. models that predict the direct and diffuse components from the global one). Here, two different approaches have been considered to solve the reverse process, i.e. the conversion from tilted to horizontal: (i) one-sensor approach and (ii) multi-sensors approach. Because only one tilted plane is involved in the one-sensor approach, a decomposition model need to be coupled with a transposition model to solve the problem. By contrast, at least two tilted planes being considered in the multi-sensors approach, only a transposition model is required to perform the conversion. First, global solar irradiance measurements recorded on the roof of the Royal Meteorological Institute of Belgium's radiation tower in Uccle were used to evaluate the performance of both approaches. Four pyranometers (one mounted in the horizontal plane and three on inclined surfaces with different tilts and orientations) were involved in the validation exercise. Second, the inverse transposition was applied to tilted global solar irradiance values retrieved from the energy production registered at residential PV systems located in the vicinity of Belgian radiometric stations operated by RMI (for validation purposes).

  7. Improved PV system reliability results from surge evaluations at Sandia National Laboratories

    SciTech Connect

    Russell H. Bonn; Sigifredo Gonzalez

    2000-04-11

    Electrical surges on ac and dc inverter power wiring and diagnostic cables have the potential to shorten the lifetime of power electronics. These surges may be caused by either nearby lightning or capacitor switching transients. This paper contains a description of ongoing surge evaluations of PV power electronics and surge mitigation hardware at Sandia.

  8. Benchmarking Non-Hardware Balance of System (Soft) Costs for U.S. Photovoltaic Systems Using a Data-Driven Analysis from PV Installer Survey Results

    SciTech Connect

    Ardani, K.; Barbose, G.; Margolis, R.; Wiser, R.; Feldman, D.; Ong, S.

    2012-11-01

    This report presents results from the first U.S. Department of Energy (DOE) sponsored, bottom-up data-collection and analysis of non-hardware balance-of-system costs--often referred to as 'business process' or 'soft' costs--for residential and commercial photovoltaic (PV) systems.

  9. Grid integrated distributed PV (GridPV).

    SciTech Connect

    Reno, Matthew J.; Coogan, Kyle

    2013-08-01

    This manual provides the documentation of the MATLAB toolbox of functions for using OpenDSS to simulate the impact of solar energy on the distribution system. The majority of the functions are useful for interfacing OpenDSS and MATLAB, and they are of generic use for commanding OpenDSS from MATLAB and retrieving information from simulations. A set of functions is also included for modeling PV plant output and setting up the PV plant in the OpenDSS simulation. The toolbox contains functions for modeling the OpenDSS distribution feeder on satellite images with GPS coordinates. Finally, example simulations functions are included to show potential uses of the toolbox functions. Each function in the toolbox is documented with the function use syntax, full description, function input list, function output list, example use, and example output.

  10. Comparison of three different methods of perturbing the potential vorticity field in mesoscale forecasts of Mediterranean heavy precipitation events: PV-gradient, PV-adjoint and PV-satellite

    NASA Astrophysics Data System (ADS)

    Vich, M.; Romero, R.; Richard, E.; Arbogast, P.; Maynard, K.

    2010-09-01

    a forecast with the corresponding perturbed initial state (PV-satellite). The non hydrostatic MM5 mesoscale model has been used to run all forecasts. The simulations are performed for a two-day period with a 22.5 km resolution domain (Domain 1 in http://mm5forecasts.uib.es) nested in the ECMWF large-scale forecast fields. The MEDEX cyclone of 10 June 2000, also known as the Montserrat Case, is a suitable testbed to compare the performance of each ensemble and the PV-satellite method. This case is characterized by an Atlantic upper-level trough and low-level cold front which generated a stationary mesoscale cyclone over the Spanish Mediterranean coast, advecting warm and moist air toward Catalonia from the Mediterranean Sea. The consequences of the resulting mesoscale convective system were 6-h accumulated rainfall amounts of 180 mm with estimated material losses to exceed 65 million euros by media. The performace of both ensemble forecasting systems and PV-satellite technique for our case study is evaluated through the verification of the rainfall field. Since the EPSs are probabilistic forecasts and the PV-satellite is deterministic, their comparison is done using the individual ensemble members. Therefore the verification procedure uses deterministic scores, like the ROC curve, the Taylor diagram or the Q-Q plot. These scores cover the different quality attributes of the forecast such as reliability, resolution, uncertainty and sharpness. The results show that the PV-satellite technique performance lies within the performance range obtained by both ensembles; it is even better than the non-perturbed ensemble member. Thus, perturbing randomly using the PV error climatology and introducing the perturbations in the zones given by each EPS captures the mismatch between PV and WV fields better than manual perturbations made by an expert forecaster, at least for this case study.

  11. Large gap magnetic suspension system

    NASA Technical Reports Server (NTRS)

    Abdelsalam, Moustafa K.; Eyssa, Y. M.

    1991-01-01

    The design of a large gap magnetic suspension system is discussed. Some of the topics covered include: the system configuration, permanent magnet material, levitation magnet system, superconducting magnets, resistive magnets, superconducting levitation coils, resistive levitation coils, levitation magnet system, and the nitrogen cooled magnet system.

  12. Grid-connected photovoltaic (PV) systems with batteries storage as solution to electrical grid outages in Burkina Faso

    NASA Astrophysics Data System (ADS)

    Abdoulaye, D.; Koalaga, Z.; Zougmore, F.

    2012-02-01

    This paper deals with a key solution for power outages problem experienced by many African countries and this through grid-connected photovoltaic (PV) systems with batteries storage. African grids are characterized by an insufficient power supply and frequent interruptions. Due to this fact, users who especially use classical grid-connected photovoltaic systems are unable to profit from their installation even if there is sun. In this study, we suggest the using of a grid-connected photovoltaic system with batteries storage as a solution to these problems. This photovoltaic system works by injecting the surplus of electricity production into grid and can also deliver electricity as a stand-alone system with all security needed. To achieve our study objectives, firstly we conducted a survey of a real situation of one African electrical grid, the case of Burkina Faso (SONABEL: National Electricity Company of Burkina). Secondly, as study case, we undertake a sizing, a modeling and a simulation of a grid-connected PV system with batteries storage for the LAME laboratory at the University of Ouagadougou. The simulation shows that the proposed grid-connected system allows users to profit from their photovoltaic installation at any time even if the public electrical grid has some failures either during the day or at night.

  13. A New Control Method to Mitigate Power Fluctuations for Grid Integrated PV/Wind Hybrid Power System Using Ultracapacitors

    NASA Astrophysics Data System (ADS)

    Jayalakshmi, N. S.; Gaonkar, D. N.

    2016-08-01

    The output power obtained from solar-wind hybrid system fluctuates with changes in weather conditions. These power fluctuations cause adverse effects on the voltage, frequency and transient stability of the utility grid. In this paper, a control method is presented for power smoothing of grid integrated PV/wind hybrid system using ultracapacitors in a DC coupled structure. The power fluctuations of hybrid system are mitigated and smoothed power is supplied to the utility grid. In this work both photovoltaic (PV) panels and the wind generator are controlled to operate at their maximum power point. The grid side inverter control strategy presented in this paper maintains DC link voltage constant while injecting power to the grid at unity power factor considering different operating conditions. Actual solar irradiation and wind speed data are used in this study to evaluate the performance of the developed system using MATLAB/Simulink software. The simulation results show that output power fluctuations of solar-wind hybrid system can be significantly mitigated using the ultracapacitor based storage system.

  14. U.S. Aims for Zero-Energy: Support for PV on New Homes

    SciTech Connect

    Barbose, Galen; Wiser, Ryan; Bolinger, Mark

    2006-05-11

    As a market segment for solar photovoltaic (PV) adoption, new homes have a number of attractive attributes. Homebuyers can easily roll the cost of the PV system into their mortgage and, with rebates or other financial incentives, potentially realize an immediate net positive cash flow from the investment. PV system performance can be optimized by taking roof orientation, shading, and other structural factors into account in the design of new homes. Building-integrated photovoltaics (BIPV), which are subject to fewer aesthetic concerns than traditional, rack-mounted systems, are well-suited to new construction applications. In large new residential developments, costs can be reduced through bulk purchases and scale economies in system design and installation. Finally, the ability to install PV as a standard feature in new developments - like common household appliances - creates an opportunity to circumvent the high transaction costs and other barriers typically confronted when each individual homeowner must make a distinct PV purchase decision.

  15. Minimum Capacity of NaS Battery according to Capacity of PV System in a Microgrid under 30 min Power Balancing Control

    NASA Astrophysics Data System (ADS)

    Shimakage, Toyonari; Sone, Akihito; Sumita, Jiro; Kato, Takeyoshi; Suzuoki, Yasuo

    On constructing a microgrid, it is essential to design capacity of photovoltaic power generation (PV) systems and storage batteries in accordance with a control target. In this study, we constructed a simulation model of energy control system in the microgrid used in the demonstration project. By using this model, we investigated the minimum capacity of NaS battery for different PV system capacities for keeping the target power imbalance within ±3% over 30 min. The main results are as follows. The microgrid involving 330-kW PV systems (corresponding to the actual system) needs a NaS battery capacity of at least approximately ±20kW, and PV systems with a capacity up to about 890kW can be integrated in the microgrid with a NaS battery capacity of ±500kW (corresponding to the actual system). We estimated the minimum capacity of NaS battery for different PV system capacities and clarified that the output behavior of the NaS battery and PAFC when supply and demand power imbalance over 30 min. exceeds the ±3% limit. We suggested the improved control model and showed that it is effective in decreasing the minimum capacity of NaS battery, although it has negative effects on the reduction of short-period power flow fluctuation at the grid-connection point.

  16. System and Battery Charge Control for PV-Powered AC Lighting Systems

    SciTech Connect

    Kern, G.

    1999-04-01

    This report reviews a number of issues specific to stand-alone AC lighting systems. A review of AC lighting technology is presented, which discusses the advantages and disadvantages of various lamps. The best lamps for small lighting systems are compact fluorescent. The best lamps for intermediate-size systems are high- or low-pressure sodium. Specifications for battery charging and load control are provided with the goal of achieving lamp lifetimes on the order of 16,000 to 24,000 hours and battery lifetimes of 4 to 5 years. A rough estimate of the potential domestic and global markets for stand-alone AC lighting systems is presented. DC current injection tests were performed on high-pressure sodium lamps and the test results are presented. Finally, a prototype system was designed and a prototype system controller (with battery charger and DC/AC inverter) was developed and built.

  17. Energy Management System Lowers U.S. Navy Energy Costs Through PV System Interconnection (Fact Sheet)

    SciTech Connect

    Not Available

    2014-04-01

    To meet the U.S. Navy's energy goals, the National Renewable Energy Laboratory (NREL) and the Naval Facilities Engineering Command (NAVFAC) spent two years collaborating on demonstrations that tested market-ready energy efficiency measures, renewable energy generation, and energy systems integration. One such technology - an energy management system - was identified as a promising method for reducing energy use and costs, and can contribute to increasing energy security.

  18. Supported PV module assembly

    DOEpatents

    Mascolo, Gianluigi; Taggart, David F.; Botkin, Jonathan D.; Edgett, Christopher S.

    2013-10-15

    A supported PV assembly may include a PV module comprising a PV panel and PV module supports including module supports having a support surface supporting the module, a module registration member engaging the PV module to properly position the PV module on the module support, and a mounting element. In some embodiments the PV module registration members engage only the external surfaces of the PV modules at the corners. In some embodiments the assembly includes a wind deflector with ballast secured to a least one of the PV module supports and the wind deflector. An array of the assemblies can be secured to one another at their corners to prevent horizontal separation of the adjacent corners while permitting the PV modules to flex relative to one another so to permit the array of PV modules to follow a contour of the support surface.

  19. Lightweight IMM PV Flexible Blanket Assembly

    NASA Technical Reports Server (NTRS)

    Spence, Brian

    2015-01-01

    Deployable Space Systems (DSS) has developed an inverted metamorphic multijunction (IMM) photovoltaic (PV) integrated modular blanket assembly (IMBA) that can be rolled or z-folded. This IMM PV IMBA technology enables a revolutionary flexible PV blanket assembly that provides high specific power, exceptional stowed packaging efficiency, and high-voltage operation capability. DSS's technology also accommodates standard third-generation triple junction (ZTJ) PV device technologies to provide significantly improved performance over the current state of the art. This SBIR project demonstrated prototype, flight-like IMM PV IMBA panel assemblies specifically developed, designed, and optimized for NASA's high-voltage solar array missions.

  20. Solar PV O&M Standards and Best Practices - Existing Gaps and Improvement Efforts

    SciTech Connect

    Klise, Geoffrey Taylor; Balfour, John R.; Keating, T. J.

    2014-11-01

    As greater numbers of photovoltaic (PV) systems are being installed, operations & maintenance (O&M) activities will need to be performed to ensure the PV system is operating as designed over its useful lifetime. To mitigate risks to PV system availability and performance, standardized procedures for O&M activities are needed to ensure high reliability and long-term system bankability. Efforts are just getting underway to address the need for standard O&M procedures as PV gains a larger share of U.S. generation capacity. Due to the existing landscape of how and where PV is installed, including distributed generation from small and medium PV systems, as well as large, centralized utility-scale PV, O&M activities will require different levels of expertise and reporting, making standards even more important. This report summarizes recent efforts made by solar industry stakeholders to identify the existing standards and best practices applied to solar PV O&M activities, and determine the gaps that have yet to be, or are currently being addressed by industry.

  1. Solar PV O&M Standards and Best Practices – Existing Gaps and Improvement Efforts

    SciTech Connect

    Klise, Geoffrey Taylor; Balfour, John R.; Keating, T. J.

    2014-11-01

    As greater numbers of photovoltaic (PV) systems are being installed, operations & maintenance (O&M) activities will need to be performed to ensure the PV system is operating as designed over its useful lifetime. To mitigate risks to PV system availability and performance, standardized procedures for O&M activities are needed to ensure high reliability and long-term system bankability. Efforts are just getting underway to address the need for standard O&M procedures as PV gains a larger share of U.S. generation capacity. Due to the existing landscape of how and where PV is installed, including distributed generation from small and medium PV systems, as well as large, centralized utility-scale PV, O&M activities will require different levels of expertise and reporting, making standards even more important. This report summarizes recent efforts made by solar industry stakeholders to identify the existing standards and best practices applied to solar PV O&M activities, and determine the gaps that have yet to be, or are currently being addressed by industry.

  2. Fault current reduction by SFCL in a distribution system with PV using fuzzy logic technique

    NASA Astrophysics Data System (ADS)

    Mounika, M.; Lingareddy, P.

    2017-07-01

    In the modern power system, as the utilization of electric power is very wide, there is a frequent occurring of any fault or disturbance in power system. It causes a high short circuit current. Due to this fault, high currents occurs results to large mechanical forces, these forces cause overheating of the equipment. If the large size equipment are used in power system then they need a large protection scheme for severe fault conditions. Generally, the maintenance of electrical power system reliability is more important. But the elimination of fault is not possible in power systems. So the only alternate solution is to minimize the fault currents. For this the Super Conducting Fault Current Limiter using fuzzy logic technique is the best electric equipment which is used for reducing the severe fault current levels. In this paper, we simulated the unsymmetrical and symmetrical faults with fuzzy based superconducting fault current limiter. In our analysis it is proved that, fuzzy logic based super conducting fault current limiter reduces fault current quickly to a lower value.

  3. Analysis of PV Advanced Inverter Functions and Setpoints under Time Series Simulation.

    SciTech Connect

    Seuss, John; Reno, Matthew J.; Broderick, Robert Joseph; Grijalva, Santiago

    2016-05-01

    Utilities are increasingly concerned about the potential negative impacts distributed PV may have on the operational integrity of their distribution feeders. Some have proposed novel methods for controlling a PV system's grid - tie inverter to mitigate poten tial PV - induced problems. This report investigates the effectiveness of several of these PV advanced inverter controls on improving distribution feeder operational metrics. The controls are simulated on a large PV system interconnected at several locations within two realistic distribution feeder models. Due to the time - domain nature of the advanced inverter controls, quasi - static time series simulations are performed under one week of representative variable irradiance and load data for each feeder. A para metric study is performed on each control type to determine how well certain measurable network metrics improve as a function of the control parameters. This methodology is used to determine appropriate advanced inverter settings for each location on the f eeder and overall for any interconnection location on the feeder.

  4. Hybrid PV/diesel solar power system design using multi-level factor analysis optimization

    NASA Astrophysics Data System (ADS)

    Drake, Joshua P.

    Solar power systems represent a large area of interest across a spectrum of organizations at a global level. It was determined that a clear understanding of current state of the art software and design methods, as well as optimization methods, could be used to improve the design methodology. Solar power design literature was researched for an in depth understanding of solar power system design methods and algorithms. Multiple software packages for the design and optimization of solar power systems were analyzed for a critical understanding of their design workflow. In addition, several methods of optimization were studied, including brute force, Pareto analysis, Monte Carlo, linear and nonlinear programming, and multi-way factor analysis. Factor analysis was selected as the most efficient optimization method for engineering design as it applied to solar power system design. The solar power design algorithms, software work flow analysis, and factor analysis optimization were combined to develop a solar power system design optimization software package called FireDrake. This software was used for the design of multiple solar power systems in conjunction with an energy audit case study performed in seven Tibetan refugee camps located in Mainpat, India. A report of solar system designs for the camps, as well as a proposed schedule for future installations was generated. It was determined that there were several improvements that could be made to the state of the art in modern solar power system design, though the complexity of current applications is significant.

  5. Measurement system for determination of current-voltage characteristics of PV modules

    NASA Astrophysics Data System (ADS)

    Idzkowski, Adam; Walendziuk, Wojciech; Borawski, Mateusz; Sawicki, Aleksander

    2015-09-01

    The realization of a laboratory stand for testing photovoltaic panels is presented here. The project of the laboratory stand was designed in SolidWorks software. The aim of the project was to control the electrical parameters of a PV panel. For this purpose a meter that measures electrical parameters i.e. voltage, current and power, was realized. The meter was created with the use of LabJack DAQ device and LabVIEW software. The presented results of measurements were obtained in different conditions (variable distance from the source of light, variable tilt angle of the panel). Current voltage characteristics of photovoltaic panel were created and all parameters could be detected in different conditions. The standard uncertainties of sample voltage, current, power measurements were calculated. The paper also gives basic information about power characteristics and efficiency of a solar cell.

  6. PV Hourly Simulation Tool

    SciTech Connect

    Dean, Jesse; Metzger, Ian

    2010-12-31

    This software requires inputs of simple general building characteristics and usage information to calculate the energy and cost benefits of solar PV. This tool conducts and complex hourly simulation of solar PV based primarily on the area available on the rooftop. It uses a simplified efficiency calculation method and real panel characteristics. It includes a detailed rate structure to account for time-of-use rates, on-peak and off-peak pricing, and multiple rate seasons. This tool includes the option for advanced system design inputs if they are known. This tool calculates energy savings, demand reduction, cost savings, incentives and building life cycle costs including: simple payback, discounted payback, net-present value, and savings to investment ratio. In addition this tool also displays the environmental benefits of a project.

  7. Development of a low-cost integrated 20-kW ac solar tracking sub- array for grid-connected PV power system applications. Phase 1, Annual technical report, 11 July 1995--31 July 1996

    SciTech Connect

    Stern, M.; West, R.; Fourer, G.; Whalen, W.; Van Loo, M.; Duran, G.

    1997-06-01

    The overall goal of this effort is to reduce the installed cost of utility scale grid connected photovoltaic power systems. The focus of the effort is on ``BOS`` (Balance-Of-System) component manufacturing technology, which essentially involves all PV power system engineering, manufacturing, assembly and construction tasks from the receipt of a PV module to the deliver of grid connected electricity.

  8. Functional characterization of the Xcs and Xps type II secretion systems from the plant pathogenic bacterium Xanthomonas campestris pv vesicatoria.

    PubMed

    Szczesny, Robert; Jordan, Matthias; Schramm, Claudia; Schulz, Steve; Cogez, Virginie; Bonas, Ulla; Büttner, Daniela

    2010-09-01

    *Type II secretion (T2S) systems of many plant-pathogenic bacteria often secrete cell wall-degrading enzymes into the plant apoplast. *Here, we show that the Xps-T2S system from the plant pathogen Xanthomonas campestris pv vesicatoria (Xcv) promotes disease and contributes to the translocation of effector proteins that are delivered into the plant cell by the type III secretion (T3S) system. *The Xcs-T2S system instead lacks an obvious virulence function. However, individual xcs genes can partially complement mutants in homologous xps genes, indicating that they encode functional components of T2S systems. Enzyme activity assays showed that the Xps system contributes to secretion of proteases and xylanases. We identified the virulence-associated xylanase XynC as a substrate of the Xps system. However, homologs of known T2S substrates from other Xanthomonas spp. are not secreted by the T2S systems from Xcv. Thus, T2S systems from Xanthomonas spp. appear to differ significantly in their substrate specificities. *Transcript analyses revealed that expression of xps genes in Xcv is activated by HrpG and HrpX, key regulators of the T3S system. By contrast, expression of xynC and extracellular protease and xylanase activities are repressed by HrpG and HrpX, suggesting that components and substrates of the Xps system are differentially regulated.

  9. Analysis of Photovoltaic (PV) Module during Partial Shading based on Simplified Two-Diode Model

    NASA Astrophysics Data System (ADS)

    Chitti Babu, B.; Gurjar, Suresh; Meher, Ashish

    2015-02-01

    Generally, the characteristics of photovoltaic (PV) array are largely affected by solar temperature, solar irradiance, shading patterns, array configuration and location of shading modules. Partial shading is due to moving clouds and shadows of nearby obstacles and can cause a significant degradation in the output of PV system. Hence, the characteristics of PV array get more multifaceted with multiple peaks. The ultimate aim of the paper is to analyze the performance of PV module during such adverse condition based on simplified two-diode model. To reduce the computational time, the simplified two-diode model has a photocurrent source in parallel with two ideal diodes. Only four parameters are required to be calculated from datasheet in order to simulate the model. Moreover, the performance of PV array is evaluated at different shaded patterns and it is found that the model has less computational time and gives accurate results.

  10. Wavelet Based Protection Scheme for Multi Terminal Transmission System with PV and Wind Generation

    NASA Astrophysics Data System (ADS)

    Manju Sree, Y.; Goli, Ravi kumar; Ramaiah, V.

    2017-08-01

    A hybrid generation is a part of large power system in which number of sources usually attached to a power electronic converter and loads are clustered can operate independent of the main power system. The protection scheme is crucial against faults based on traditional over current protection since there are adequate problems due to fault currents in the mode of operation. This paper adopts a new approach for detection, discrimination of the faults for multi terminal transmission line protection in presence of hybrid generation. Transient current based protection scheme is developed with discrete wavelet transform. Fault indices of all phase currents at all terminals are obtained by analyzing the detail coefficients of current signals using bior 1.5 mother wavelet. This scheme is tested for different types of faults and is found effective for detection and discrimination of fault with various fault inception angle and fault impedance.

  11. Budgeting for Solar PV Plant Operations & Maintenance: Practices and Pricing.

    SciTech Connect

    Enbar, Nadav; Weng, Dean; Klise, Geoffrey Taylor

    2015-12-01

    With rising grid interconnections of solar photovoltaic (PV) systems, greater attention is being trained on lifecycle performance, reliability, and project economics. Expected to meet production thresholds over a 20-30 year timeframe, PV plants require a steady diet of operations and maintenance (O&M) oversight to meet contractual terms. However, industry best practices are only just beginning to emerge, and O&M budgets—given the arrangement of the solar project value chain—appear to vary widely. Based on insights from in-depth interviews and survey research, this paper presents an overview of the utility-scale PV O&M budgeting process along with guiding rationales, before detailing perspectives on current plant upkeep activities and price points largely in the U.S. It concludes by pondering potential opportunities for improving upon existing O&M budgeting approaches in ways that can benefi t the industry at-large.

  12. Budgeting for Solar PV Plant Operations & Maintenance: Practices and Pricing.

    SciTech Connect

    Enbar, Nadav; Weng, Dean; Klise, Geoffrey Taylor

    2016-01-01

    With rising grid interconnections of solar photovoltaic (PV) systems, greater attention is being trained on lifecycle performance, reliability, and project economics. Expected to meet production thresholds over a 20-30 year timeframe, PV plants require a steady diet of operations and maintenance (O&M) oversight to meet contractual terms. However, industry best practices are only just beginning to emerge, and O&M budgets—given the arrangement of the solar project value chain—appear to vary widely. Based on insights from in-depth interviews and survey research, this paper presents an overview of the utility-scale PV O&M budgeting process along with guiding rationales, before detailing perspectives on current plant upkeep activities and price points largely in the U.S. It concludes by pondering potential opportunities for improving upon existing O&M budgeting approaches in ways that can benefit the industry at-large.

  13. Estimation of Curve Tracing Time in Supercapacitor based PV Characterization

    NASA Astrophysics Data System (ADS)

    Basu Pal, Sudipta; Das Bhattacharya, Konika; Mukherjee, Dipankar; Paul, Debkalyan

    2017-01-01

    Smooth and noise-free characterisation of photovoltaic (PV) generators have been revisited with renewed interest in view of large size PV arrays making inroads into the urban sector of major developing countries. Such practice has recently been observed to be confronted by the use of a suitable data acquisition system and also the lack of a supporting theoretical analysis to justify the accuracy of curve tracing. However, the use of a selected bank of supercapacitors can mitigate the said problems to a large extent. Assuming a piecewise linear analysis of the V-I characteristics of a PV generator, an accurate analysis of curve plotting time has been possible. The analysis has been extended to consider the effect of equivalent series resistance of the supercapacitor leading to increased accuracy (90-95%) of curve plotting times.

  14. Estimation of Curve Tracing Time in Supercapacitor based PV Characterization

    NASA Astrophysics Data System (ADS)

    Basu Pal, Sudipta; Das Bhattacharya, Konika; Mukherjee, Dipankar; Paul, Debkalyan

    2017-08-01

    Smooth and noise-free characterisation of photovoltaic (PV) generators have been revisited with renewed interest in view of large size PV arrays making inroads into the urban sector of major developing countries. Such practice has recently been observed to be confronted by the use of a suitable data acquisition system and also the lack of a supporting theoretical analysis to justify the accuracy of curve tracing. However, the use of a selected bank of supercapacitors can mitigate the said problems to a large extent. Assuming a piecewise linear analysis of the V-I characteristics of a PV generator, an accurate analysis of curve plotting time has been possible. The analysis has been extended to consider the effect of equivalent series resistance of the supercapacitor leading to increased accuracy (90-95%) of curve plotting times.

  15. Extending Performance and Evaluating Risks of PV Systems Failure Using a Fault Tree and Event Tree Approach: Analysis of the Possible Application

    SciTech Connect

    Colli A.

    2012-06-03

    Performance and reliability of photovoltaic (PV) systems are important issues in the overall evaluation of a PV plant and its components. While performance is connected to the amount of energy produced by the PV installation in the working environmental conditions, reliability impacts the availability of the system to produce the expected amount of energy. In both cases, the evaluation should be done considering information and data coming from indoor as well as outdoor tests. In this paper a way of re-thinking performance, giving it a probabilistic connotation, and connecting the two concepts of performance and reliability is proposed. The paper follows a theoretical approach and discusses the way to obtaining such information, facing benefits and problems. The proposed probabilistic performance accounts for the probability of the system to function correctly, thus passing through the complementary evaluation of the probability of system malfunctions and consequences. Scenarios have to be identified where the system is not functioning properly or at all. They are expected to be combined in a probabilistic safety analysis (PSA) based approach, providing not only the required probability, but also being capable of giving a prioritization of the risks and the most dominant scenario associated to a specific situation. This approach can offer the possibility to highlight the most critical parts of a PV system, as well as providing support in design activities identifying weak connections.

  16. Large-Scale Information Systems

    SciTech Connect

    D. M. Nicol; H. R. Ammerlahn; M. E. Goldsby; M. M. Johnson; D. E. Rhodes; A. S. Yoshimura

    2000-12-01

    Large enterprises are ever more dependent on their Large-Scale Information Systems (LSLS), computer systems that are distinguished architecturally by distributed components--data sources, networks, computing engines, simulations, human-in-the-loop control and remote access stations. These systems provide such capabilities as workflow, data fusion and distributed database access. The Nuclear Weapons Complex (NWC) contains many examples of LSIS components, a fact that motivates this research. However, most LSIS in use grew up from collections of separate subsystems that were not designed to be components of an integrated system. For this reason, they are often difficult to analyze and control. The problem is made more difficult by the size of a typical system, its diversity of information sources, and the institutional complexities associated with its geographic distribution across the enterprise. Moreover, there is no integrated approach for analyzing or managing such systems. Indeed, integrated development of LSIS is an active area of academic research. This work developed such an approach by simulating the various components of the LSIS and allowing the simulated components to interact with real LSIS subsystems. This research demonstrated two benefits. First, applying it to a particular LSIS provided a thorough understanding of the interfaces between the system's components. Second, it demonstrated how more rapid and detailed answers could be obtained to questions significant to the enterprise by interacting with the relevant LSIS subsystems through simulated components designed with those questions in mind. In a final, added phase of the project, investigations were made on extending this research to wireless communication networks in support of telemetry applications.

  17. The RpfB-Dependent Quorum Sensing Signal Turnover System Is Required for Adaptation and Virulence in Rice Bacterial Blight Pathogen Xanthomonas oryzae pv. oryzae.

    PubMed

    Wang, Xing-Yu; Zhou, Lian; Yang, Jun; Ji, Guang-Hai; He, Ya-Wen

    2016-03-01

    Xanthomonas oryzae pv. oryzae, the bacterial blight pathogen of rice, produces diffusible signal factor (DSF) family quorum sensing signals to regulate virulence. The biosynthesis and perception of DSF family signals require components of the rpf (regulation of pathogenicity factors) cluster. In this study, we report that RpfB plays an essential role in DSF family signal turnover in X. oryzae pv. oryzae PXO99A. The production of DSF family signals was boosted by deletion of the rpfB gene and was abolished by its overexpression. The RpfC/RpfG-mediated DSF signaling system negatively regulates rpfB expression via the global transcription regulator Clp, whose activity is reversible in the presence of cyclic diguanylate monophosphate. These findings indicate that the DSF family signal turnover system in PXO99A is generally consistent with that in Xanthomonas campestris pv. campestris. Moreover, this study has revealed several specific roles of RpfB in PXO99A. First, the rpfB deletion mutant produced high levels of DSF family signals but reduced extracellular polysaccharide production, extracellular amylase activity, and attenuated pathogenicity. Second, the rpfB/rpfC double-deletion mutant was partially deficient in xanthomonadin production. Taken together, the RpfB-dependent DSF family signal turnover system is a conserved and naturally presenting signal turnover system in Xanthomonas spp., which plays unique roles in X. oryzae pv. oryzae adaptation and pathogenesis.

  18. An ECF sigma factor mediated cell surface signaling system in Pseudomonas syringae pv. tomato DC3000 regulates gene expression in response to heterologous siderophores

    USDA-ARS?s Scientific Manuscript database

    The diversity of regulatory systems encoded by bacteria provides an indication of the variety of stresses and interactions that these organisms encounter in nature. We have been investigating how the plant pathogen, Pseudomonas syringae pv. tomato DC3000, responds to iron limitation and have focuse...

  19. Analysis of concentrating PV-T systems for the commercial/industrial sector. Volume IV. Design analysis and trade-off study

    SciTech Connect

    Schwinkendorf, W.E.

    1984-09-01

    Detailed reference designs developed for optimally sized photovoltaic-thermal (PV-T) systems are presented for three selected applications. The results of trade-off analyses to determine the effects of load variations, new components, changes in location, and variations in array cost are also discussed.

  20. Development of a fully-integrated PV system for residential applications: Phase I annual technical report: February 27, 1998 -- August 31, 1999

    SciTech Connect

    West, R.; Mackamul, K.; Duran, G.

    2000-03-06

    This report describes Utility Power Group's (UPG's) technical progress for Phase 1 of a two-phase effort to focus on the design, assembly, and testing of a fully-integrated residential PV power system, including storage. In the PV Array Task, UPG significantly improved the conventional means and methods required to structurally interface PV modules to the roofs of single-family residential houses and to electrically interconnect these PV modules to a power conversion unit. UPG focused on the design and test of a PV array based on the highly efficient use of materials and labor. Design criteria included cost, structural integrity, electrical safety, reliability, conformance with applicable standards and building and seismic codes, and adaptability to a wide range of roof materials for both existing and retrofit roof applications. In the Power Unit Task, UPG designed and tested a high-efficiency, low-cost, high-reliability prototype power conversion unit that included all materials, components, equipment, and software required to perform all DC-AC/AC-DC power collection, conversion, and control functions between the output of the PV array and the interconnection to the electrical grid service of single-family residences. In the Energy Storage Unit Task, UPG designed and tested a low-cost, modular, self-contained, low-maintenance, all-weather, battery-based Energy Storage Unit designed to interface with the Power Unit to provide back-up electricity to supply critical household loads in the event of utility-grid failure. The Energy Storage Unit includes batteries and all structural, mechanical, and electrical equipment required to provide a source of stored DC energy for input of the Power Unit. UPG designed the storage unit as a ''plug and play'' option, where multiple units can be easily paralleled for additional energy storage capacity.

  1. Low concentrator PV optics optimization

    NASA Astrophysics Data System (ADS)

    Sharp, Leonard; Chang, Ben

    2008-08-01

    Purpose: Cost reduction is a major focus of the solar industry. Thin film technologies and concentration systems are viable ways to reducing cost, with unique strengths and weakness for both. Most of the concentrating PV work focuses on high concentration systems for reducing energy cost. Meanwhile, many believe that low concentrators provide significant cost reduction potential while addressing the mainstream PV market with a product that acts as a flat panel replacement. This paper analyzes the relative benefit of asymmetric vs. symmetric optics for low-concentrators in light of specific PV applications. Approach: Symmetric and asymmetric concentrating PV module performance is evaluated using computer simulation to determine potential value across various geographic locations and applications. The selected optic design is modeled against standard cSi flat panels and thin film to determine application fit, system level energy density and economic value. Results: While symmetric designs may seem ideal, asymmetric designs have an advantage in energy density. Both designs are assessed for aperture, optimum concentration ratio, and ideal system array configuration. Analysis of performance across climate specific effects (diffuse, direct and circumsolar) and location specific effects (sunpath) are also presented. The energy density and energy production of low concentrators provide a compelling value proposition. More significantly, the choice of optics for a low concentrating design can affect real world performance. With the goal of maximizing energy density and return on investment, this paper presents the advantages of asymmetric optic concentration and illustrates the value of this design within specific PV applications.

  2. Large Space Antenna Systems Technology, 1984

    NASA Technical Reports Server (NTRS)

    Boyer, W. J. (Compiler)

    1985-01-01

    Mission applications for large space antenna systems; large space antenna structural systems; materials and structures technology; structural dynamics and control technology, electromagnetics technology, large space antenna systems and the Space Station; and flight test and evaluation were examined.

  3. PV output smoothing with energy storage.

    SciTech Connect

    Ellis, Abraham; Schoenwald, David Alan

    2012-03-01

    This report describes an algorithm, implemented in Matlab/Simulink, designed to reduce the variability of photovoltaic (PV) power output by using a battery. The purpose of the battery is to add power to the PV output (or subtract) to smooth out the high frequency components of the PV power that that occur during periods with transient cloud shadows on the PV array. The control system is challenged with the task of reducing short-term PV output variability while avoiding overworking the battery both in terms of capacity and ramp capability. The algorithm proposed by Sandia is purposely very simple to facilitate implementation in a real-time controller. The control structure has two additional inputs to which the battery can respond. For example, the battery could respond to PV variability, load variability or area control error (ACE) or a combination of the three.

  4. Hierarchical simulation of large system

    NASA Technical Reports Server (NTRS)

    Saab, Daniel G.

    1991-01-01

    The main problem facing current CAD tools for VLSIs is the large amount of memory required when dealing with large systems, primarily due to the circuit representation used by most current tools. This paper discusses an approach for hierarchical switch-level simulation of digital circuits. The approach exploits the hierarchy to reduce the memory requirements of the simulation, allowing the simulation of circuits that are too large to simulate at one flat level. The approach has been implemented in a hierarchical switch-level simulator, CHAMP, which runs on a SUN workstation. The program performs mixed mode simulation: parts of the circuit can be simulated faster at a behavioral level by supplying a high level software description. CHAMP allows assignable delays, and bidirectional signal flow inside circuit blocks that are represented as transistor networks as well as across the boundaries of higher level blocks. CHAMP is also unique in that it simulates directly from the hierarchical circuit description without flattening to a single level.

  5. Systems engineering for very large systems

    NASA Technical Reports Server (NTRS)

    Lewkowicz, Paul E.

    1993-01-01

    Very large integrated systems have always posed special problems for engineers. Whether they are power generation systems, computer networks or space vehicles, whenever there are multiple interfaces, complex technologies or just demanding customers, the challenges are unique. 'Systems engineering' has evolved as a discipline in order to meet these challenges by providing a structured, top-down design and development methodology for the engineer. This paper attempts to define the general class of problems requiring the complete systems engineering treatment and to show how systems engineering can be utilized to improve customer satisfaction and profit ability. Specifically, this work will focus on a design methodology for the largest of systems, not necessarily in terms of physical size, but in terms of complexity and interconnectivity.

  6. Systems engineering for very large systems

    NASA Astrophysics Data System (ADS)

    Lewkowicz, Paul E.

    Very large integrated systems have always posed special problems for engineers. Whether they are power generation systems, computer networks or space vehicles, whenever there are multiple interfaces, complex technologies or just demanding customers, the challenges are unique. 'Systems engineering' has evolved as a discipline in order to meet these challenges by providing a structured, top-down design and development methodology for the engineer. This paper attempts to define the general class of problems requiring the complete systems engineering treatment and to show how systems engineering can be utilized to improve customer satisfaction and profit ability. Specifically, this work will focus on a design methodology for the largest of systems, not necessarily in terms of physical size, but in terms of complexity and interconnectivity.

  7. DC-based smart PV-powered home energy management system based on voltage matching and RF module

    PubMed Central

    Hasan, W. Z. W.

    2017-01-01

    The main tool for measuring system efficiency in homes and offices is the energy monitoring of the household appliances’ consumption. With the help of GUI through a PC or smart phone, there are various applications that can be developed for energy saving. This work describes the design and prototype implementation of a wireless PV-powered home energy management system under a DC-distribution environment, which allows remote monitoring of appliances’ energy consumptions and power rate quality. The system can be managed by a central computer, which obtains the energy data based on XBee RF modules that access the sensor measurements of system components. The proposed integrated prototype framework is characterized by low power consumption due to the lack of components and consists of three layers: XBee-based circuit for processing and communication architecture, solar charge controller, and solar-battery-load matching layers. Six precise analogue channels for data monitoring are considered to cover the energy measurements. Voltage, current and temperature analogue signals were accessed directly from the remote XBee node to be sent in real time with a sampling frequency of 11–123 Hz to capture the possible surge power. The performance shows that the developed prototype proves the DC voltage matching concept and is able to provide accurate and precise results. PMID:28934271

  8. DC-based smart PV-powered home energy management system based on voltage matching and RF module.

    PubMed

    Sabry, Ahmad H; Hasan, W Z W; Ab Kadir, Mza; Radzi, M A M; Shafie, S

    2017-01-01

    The main tool for measuring system efficiency in homes and offices is the energy monitoring of the household appliances' consumption. With the help of GUI through a PC or smart phone, there are various applications that can be developed for energy saving. This work describes the design and prototype implementation of a wireless PV-powered home energy management system under a DC-distribution environment, which allows remote monitoring of appliances' energy consumptions and power rate quality. The system can be managed by a central computer, which obtains the energy data based on XBee RF modules that access the sensor measurements of system components. The proposed integrated prototype framework is characterized by low power consumption due to the lack of components and consists of three layers: XBee-based circuit for processing and communication architecture, solar charge controller, and solar-battery-load matching layers. Six precise analogue channels for data monitoring are considered to cover the energy measurements. Voltage, current and temperature analogue signals were accessed directly from the remote XBee node to be sent in real time with a sampling frequency of 11-123 Hz to capture the possible surge power. The performance shows that the developed prototype proves the DC voltage matching concept and is able to provide accurate and precise results.

  9. The effectiveness of small scale Photovoltaic (PV) systems design and cost analysis simulation on Saudi Arabian Economy

    NASA Astrophysics Data System (ADS)

    Almansour, Faris Abdullah

    -Tariff PV system using HOMER. The result of the simulation has been discussed, analyzed, and plotted. We also give evidence in the thesis how useful the small PV systems can be as oppose to the larger scale system that must deal with location issues.

  10. Reconciling Consumer and Utility Objectives in the Residential Solar PV Market

    NASA Astrophysics Data System (ADS)

    Arnold, Michael R.

    Today's energy market is facing large-scale changes that will affect all market players. Near the top of that list is the rapid deployment of residential solar photovoltaic (PV) systems. Yet that growing trend will be influenced multiple competing interests between various stakeholders, namely the utility, consumers and technology provides. This study provides a series of analyses---utility-side, consumer-side, and combined analyses---to understand and evaluate the effect of increases in residential solar PV market penetration. Three urban regions have been selected as study locations---Chicago, Phoenix, Seattle---with simulated load data and solar insolation data at each locality. Various time-of-use pricing schedules are investigated, and the effect of net metering is evaluated to determine the optimal capacity of solar PV and battery storage in a typical residential home. The net residential load profile is scaled to assess system-wide technical and economic figures of merit for the utility with an emphasis on intraday load profiles, ramp rates and electricity sales with increasing solar PV penetration. The combined analysis evaluates the least-cost solar PV system for the consumer and models the associated system-wide effects on the electric grid. Utility revenue was found to drop by 1.2% for every percent PV penetration increase, net metering on a monthly or annual basis improved the cost-effectiveness of solar PV but not battery storage, the removal of net metering policy and usage of an improved the cost-effectiveness of battery storage and increases in solar PV penetration reduced the system load factor. As expected, Phoenix had the most favorable economic scenario for residential solar PV, primarily due to high solar insolation. The study location---solar insolation and load profile---was also found to affect the time of year at which the largest net negative system load was realized.

  11. The importance of hybrid PV-building integration

    SciTech Connect

    Posnansky, M.; Gnos, S.; Coonen, S.

    1994-12-31

    An extensive utilization of photovoltaics for future electricity generation and for hybrid generation of electricity and thermal energy is possible, when PV-panels are designed to become a part of the building envelope itself. Large areas are available, since roofs and facades are perfectly suited for solar energy conversion. Atlantis Energy Ltd. has developed special PV-generators which fulfill at the same time the functions and requirements of conventional building elements. In the context of different R and D projects funded by the Swiss government to implement a series of typical building integrated photovoltaic systems, Atlantis Energy Ltd was entrusted to design and build various hybrid building integrated PV-power plants, four of which are described in this paper.

  12. Influence of temperature on the optical system with large diameter off-axis parabolic lenses

    NASA Astrophysics Data System (ADS)

    Su, Yaru; Ruan, Hao; Liu, Jie

    2016-10-01

    In this work, an optical system with large diameter off-axis parabolic lenses was adopted to achieve diffraction gratings by laser interference exposure. The diffraction wavefront aberration caused by temperature variations was simulated using ZEMAX. Through theoretical analysis and optical simulation, it is proved that the diffraction wavefront aberration of holographic grating caused by the pinhole's location errors (it is assumed that when the displacement of pinhole exists along one axis, the locations of the pinhole along the other two orthogonal axes are in a state of precise adjustment ) is much larger when the displacement occurs along z axis than along the other two axes, and the diffraction wavefront aberration is the smallest when the displacement occurs along x axis. If the ambient temperature changes by 1 degree, the PV value is 0.0631λ when the location of the pinhole changes by 0.121mm along z axis, 0.0034λor 0.0672λ when the location of the pinhole changes by 0.002mm along x axis or 0.03mm along y axis. To reach the diffraction limit (that means the PV value is 0.25λ), the decentering value of the pinhole along z axis should be less than 0.0341mm. In conclusion, the position error along z axis is an important factor to influence the PV value of diffraction grating, and the effect of temperature on the PV value of diffraction grating can be neglected.

  13. Accelerating PV Cost Effectiveness Through Systems Design, Engineering, and Quality Assurance: Phase I Annual Technical Report, 4 November 2004 - 3 November 2005

    SciTech Connect

    Botkin, J.

    2006-07-01

    During Phase I of this PV Manufacturing R&D subcontract, PowerLight Corporation has made significant progress toward the reduction of installed costs for commercial-scale, rooftop PV systems. PowerLight has worked to reduce operating costs by improving long-term reliability and performance through the development of more sophisticated tools used in system design and monitoring. Additionally, PowerLight has implemented design improvements with the goal of reducing cost while maintaining and/or improving product quality. As part of this effort, PowerLight also modified manufacturing and shipping processes to accommodate these design changes, streamline material flow, reduce cost, and decrease waste streams. During Phase II of this project, PowerLight plans to continue this work with the goal of reducing system cost and improving system performance.

  14. Proteomic changes in Actinidia chinensis shoot during systemic infection with a pandemic Pseudomonas syringae pv. actinidiae strain.

    PubMed

    Petriccione, Milena; Di Cecco, Ilaria; Arena, Simona; Scaloni, Andrea; Scortichini, Marco

    2013-01-14

    A pandemic, very aggressive population of Pseudomonas syringae pv. actinidiae is currently causing severe economic losses to kiwifruit crops worldwide. Upon leaf attack, this Gram-negative bacterium systemically reaches the plant shoot in a week period. In this study, combined 2-DE and nanoLC-ESI-LIT-MS/MS procedures were used to describe major proteomic changes in Actinidia chinensis shoot following bacterial inoculation in host leaf. A total of 117 differentially represented protein spots were identified in infected and control shoots. Protein species associated with plant defence, including type-members of the plant basal defence, pathogenesis, oxidative stress and heat shock, or with transport and signalling events, were the most represented category of induced components. Proteins involved in carbohydrate metabolism and photosynthesis were also augmented upon infection. In parallel, a bacterial outer membrane polypeptide component was identified in shoot tissues, whose homologues were already linked to bacterial virulence in other eukaryotes. Semiquantitative RT-PCR analysis confirmed expression data for all selected plant gene products. All these data suggest a general reprogramming of shoot metabolism following pathogen systemic infection, highlighting organ-specific differences within the context of a general similarity with respect to other pathosystems. In addition to present preliminary information on the molecular mechanisms regulating this specific plant-microbe interaction, our results will foster future proteomic studies aimed at characterizing the very early events of host colonization, thus promoting the development of novel bioassays for pathogen detection in kiwifruit material.

  15. Distributed PV Adoption - Sensitivity to Market Factors

    SciTech Connect

    Gagnon, Pieter; Sigrin, Ben

    2016-02-01

    NREL staff used the dSolar (distributed solar) model to forecast the adoption of distributed, behind-the-meter PV through the year 2050 for 9 different scenarios. The scenarios varied in their assumptions about a carbon tax, the cost of PV systems in the future, and what credit would be given for excess generation once current net metering policies expire.

  16. Complementing hydropower with PV and wind: optimal energy mix in a fully renewable Switzerland

    NASA Astrophysics Data System (ADS)

    Dujardin, Jérôme; Kahl, Annelen; Kruyt, Bert; Lehning, Michael

    2017-04-01

    Like several other countries, Switzerland plans to phase out its nuclear power production and will replace most or all of it by renewables. Switzerland has the chance to benefit from a large hydropower potential and has already exploited almost all of it. Currently about 60% of the Swiss electricity consumption is covered by hydropower, which will eventually leave a gap of about 40% to the other renewables mainly composed of photovoltaics (PV) and wind. With its high flexibility, storage hydropower will play a major role in the future energy mix, providing valuable power and energy balance. Our work focuses on the interplay between PV, wind and storage hydropower, to analyze the dynamics of this complex system and to identify the best PV-wind mixing ratio. Given the current electricity consumption and the currently installed pumping capacity of the storage hydropower plants, it appears that the Swiss hydropower system can completely alleviate the intermittency of PV and wind. However, some seasonal mismatch between production and demand will remain, but we show that oversizing the production from PV and wind or enlarging the reservoir capacity can be a solution to keep it to an acceptable level or even eliminate it. We found that PV, wind and hydropower performs the best together when the share of PV in the solar - wind mix is between 20 and 60%. These findings are quantitatively specific for Switzerland but qualitatively transferable to similar mountainous environments with abundant hydropower resources.

  17. Exploring the Economic Value of EPAct 2005's PV Tax Credits

    SciTech Connect

    Bolinger, Mark; Wiser, Ryan; Ing, Edwin

    2006-03-28

    The market for grid-connected photovoltaics (PV) in the US has grown dramatically in recent years, driven in large part by PV grant or ''buy-down'' programs in California, New Jersey, and many other states. The recent announcement of a new 11-year, $3.2 billion PV program in California suggests that state policy will continue to drive even faster growth over the next decade. Federal policy has also played a role, primarily by providing commercial PV systems access to tax benefits, including accelerated depreciation (5-year MACRS schedule) and a business energy investment tax credit (ITC). With the signing of the Energy Policy Act of 2005 (EPAct) on August 8, the federal government is poised to play a much more significant future role in supporting both commercial and residential PV systems. Specifically, EPAct increased the federal ITC for commercial PV systems from 10% to 30% of system costs, and also created a new 30% ITC (capped at $2000) for residential solar systems. Both changes went into effect on January 1, 2006, and--absent an extension (for which the solar industry has already begun lobbying)--will last for a period of two years: the new residential ITC will expire, and the 30% commercial ITC will revert back to 10%, on January 1, 2008. How much economic value do these new and expanded federal tax credits really provide to PV system purchasers? And what implications might they hold for state/utility PV grant programs? Using a generic (i.e., non-state-specific) cash flow model, this report explores these questions. We begin with a discussion of the taxability of PV grants and their interaction with federal credits, as this issue significantly affects the analysis that follows. We then calculate the incremental value of EPAct's new and expanded credits for PV systems of different sizes, and owned by different types of entities. We conclude with a discussion of potential implications for purchasers of PV systems, as well as for administrators of state

  18. Optimization and life-cycle cost of health clinic PV system for a rural area in southern Iraq using HOMER software

    SciTech Connect

    Al-Karaghouli, Ali; Kazmerski, L.L.

    2010-04-15

    This paper addresses the need for electricity of rural areas in southern Iraq and proposes a photovoltaic (PV) solar system to power a health clinic in that region. The total daily health clinic load is 31.6 kW h and detailed loads are listed. The National Renewable Energy Laboratory (NREL) optimization computer model for distributed power, ''HOMER,'' is used to estimate the system size and its life-cycle cost. The analysis shows that the optimal system's initial cost, net present cost, and electricity cost is US$ 50,700, US$ 60,375, and US$ 0.238/kW h, respectively. These values for the PV system are compared with those of a generator alone used to supply the load. We found that the initial cost, net present cost of the generator system, and electricity cost are US$ 4500, US$ 352,303, and US$ 1.332/kW h, respectively. We conclude that using the PV system is justified on humanitarian, technical, and economic grounds. (author)

  19. Flexible packaging for PV modules

    NASA Astrophysics Data System (ADS)

    Dhere, Neelkanth G.

    2008-08-01

    Economic, flexible packages that provide needed level of protection to organic and some other PV cells over >25-years have not yet been developed. However, flexible packaging is essential in niche large-scale applications. Typical configuration used in flexible photovoltaic (PV) module packaging is transparent frontsheet/encapsulant/PV cells/flexible substrate. Besides flexibility of various components, the solder bonds should also be flexible and resistant to fatigue due to cyclic loading. Flexible front sheets should provide optical transparency, mechanical protection, scratch resistance, dielectric isolation, water resistance, UV stability and adhesion to encapsulant. Examples are Tefzel, Tedlar and Silicone. Dirt can get embedded in soft layers such as silicone and obscure light. Water vapor transmittance rate (WVTR) of polymer films used in the food packaging industry as moisture barriers are ~0.05 g/(m2.day) under ambient conditions. In comparison, light emitting diodes employ packaging components that have WVTR of ~10-6 g/(m2.day). WVTR of polymer sheets can be improved by coating them with dense inorganic/organic multilayers. Ethylene vinyl acetate, an amorphous copolymer used predominantly by the PV industry has very high O2 and H2O diffusivity. Quaternary carbon chains (such as acetate) in a polymer lead to cleavage and loss of adhesional strength at relatively low exposures. Reactivity of PV module components increases in presence of O2 and H2O. Adhesional strength degrades due to the breakdown of structure of polymer by reactive, free radicals formed by high-energy radiation. Free radical formation in polymers is reduced when the aromatic rings are attached at regular intervals. This paper will review flexible packaging for PV modules.

  20. Fire resistant PV shingle assembly

    DOEpatents

    Lenox, Carl J.

    2012-10-02

    A fire resistant PV shingle assembly includes a PV assembly, including PV body, a fire shield and a connection member connecting the fire shield below the PV body, and a support and inter-engagement assembly. The support and inter-engagement assembly is mounted to the PV assembly and comprises a vertical support element, supporting the PV assembly above a support surface, an upper interlock element, positioned towards the upper PV edge, and a lower interlock element, positioned towards the lower PV edge. The upper interlock element of one PV shingle assembly is inter-engageable with the lower interlock element of an adjacent PV shingle assembly. In some embodiments the PV shingle assembly may comprise a ventilation path below the PV body. The PV body may be slidably mounted to the connection member to facilitate removal of the PV body.

  1. Large and small photovoltaic powerplants

    NASA Astrophysics Data System (ADS)

    Cormode, Daniel

    The installed base of photovoltaic power plants in the United States has roughly doubled every 1 to 2 years between 2008 and 2015. The primary economic drivers of this are government mandates for renewable power, falling prices for all PV system components, 3rd party ownership models, and a generous tariff scheme known as net-metering. Other drivers include a desire for decreasing the environmental impact of electricity generation and a desire for some degree of independence from the local electric utility. The result is that in coming years, PV power will move from being a minor niche to a mainstream source of energy. As additional PV power comes online this will create challenges for the electric grid operators. We examine some problems related to large scale adoption of PV power in the United States. We do this by first discussing questions of reliability and efficiency at the PV system level. We measure the output of a fleet of small PV systems installed at Tucson Electric Power, and we characterize the degradation of those PV systems over several years. We develop methods to predict energy output from PV systems and quantify the impact of negatives such as partial shading, inverter inefficiency and malfunction of bypass diodes. Later we characterize the variability from large PV systems, including fleets of geographically diverse utility scale power plants. We also consider the power and energy requirements needed to smooth those systems, both from the perspective of an individual system and as a fleet. Finally we report on experiments from a utility scale PV plus battery hybrid system deployed near Tucson, Arizona where we characterize the ability of this system to produce smoothly ramping power as well as production of ancillary energy services such as frequency response.

  2. Large space systems technology, 1981. [conferences

    NASA Technical Reports Server (NTRS)

    Boyer, W. J. (Compiler)

    1982-01-01

    A total systems approach including structures, analyses, controls, and antennas is presented as a cohesive, programmatic plan for large space systems. Specifically, program status, structures, materials, and analyses, and control of large space systems are addressed.

  3. The Impact of Retail Rate Structures on the Economics ofCustomer-Sited PV: A Study of Commercial Installations inCalifornia

    SciTech Connect

    Wiser, Ryan; Mills, Andrew; Barbose, Galen; Golove, William

    2007-06-01

    We analyze the impact of retail rate design on the economics of grid-connected commercial photovoltaic (PV) systems in California. The analysis is based on 15-minute interval building load and PV production data for 24 commercial PV installations in California, spanning a diverse set of building load shapes and geographic locations. We derive the annual bill savings per kWh generated for each PV system, under each of 21 distinct retail rates currently offered by the five largest utilities in California. We identify and explain variation in the value of bill savings attributable to differences in the structure of demand and energy charges across rates, as well as variation attributable to other factors, such as the size of the PV system relative to building load, the specific shape of the PV production profile, and the customer load profile. We also identify the optimal rate for each customer, among those rates offered as alternatives to one another, and show how the decision is driven in large measure by the size of the PV system relative to building load. The findings reported here may be of value to regulators and utilities responsible for designing retail rates, as well as to customers and PV retailers who have a need to estimate the prospective bill savings of PV systems.

  4. Testing and Analysis for Lifetime Prediction of Crystalline Silicon PV Modules Undergoing Degradation by System Voltage Stress: Preprint

    SciTech Connect

    Hacke, P.; Smith, R.; Terwiliger, K.; Glick, S.; Jordan, D.; Johnston, S.; Kempe, M.; Kurtz, S.

    2012-07-01

    Acceleration factors are calculated for crystalline silicon PV modules under system voltage stress by comparing the module power during degradation outdoors to that in accelerated testing at three temperatures and 85% relative humidity. A lognormal analysis is applied to the accelerated lifetime test data considering failure at 80% of the initial module power. Activation energy of 0.73 eV for the rate of failure is determined, and the probability of module failure at an arbitrary temperature is predicted. To obtain statistical data for multiple modules over the course of degradation in-situ of the test chamber, dark I-V measurements are obtained and transformed using superposition, which is found well suited for rapid and quantitative evaluation of potential-induced degradation. It is determined that shunt resistance measurements alone do not represent the extent of power degradation. This is explained with a two-diode model analysis that shows an increasing second diode recombination current and ideality factor as the degradation in module power progresses. Failure modes of the modules stressed outdoors are examined and compared to those stressed in accelerated tests.

  5. A Blue Light Inducible Two-Component Signal Transduction System in the Plant Pathogen Pseudomonas syringae pv. tomato☆

    PubMed Central

    Cao, Z.; Buttani, V.; Losi, A.; Gärtner, W.

    2008-01-01

    Abstract The open reading frame PSPTO2896 from the plant pathogen Pseudomonas syringae pv. tomato encodes a protein of 534 amino acids showing all salient features of a blue light-driven two-component system. The N-terminal LOV (light, oxygen, voltage) domain, potentially binding a flavin chromophore, is followed by a histidine kinase (HK) motif and a response regulator (RR). The full-length protein (PST-LOV) and, separately, the RR and the LOV+HK part (PST-LOVΔRR) were heterologously expressed and functionally characterized. The two LOV proteins showed typical LOV-like spectra and photochemical reactions, with the blue light-driven, reversible formation of a covalent flavin-cysteine bond. The fluorescence changes in the lit state of full-length PST-LOV, but not in PST-LOVΔRR, indicating a direct interaction between the LOV core and the RR module. Experiments performed with radioactive ATP uncover the light-driven kinase activity. For both PST-LOV and PST-LOVΔRR, much more radioactivity is incorporated when the protein is in the lit state. Furthermore, addition of the RR domain to the fully phosphorylated PST-LOVΔRR leads to a very fast transfer of radioactivity, indicating a highly efficient HK activity and a tight interaction between PST-LOVΔRR and RR, possibly facilitated by the LOV core itself. PMID:17905842

  6. Construction of EGFP-labeling system for visualizing the infection process of Xanthomonas axonopodis pv. citri in planta.

    PubMed

    Liu, Li-Ping; Deng, Zi-Niu; Qu, Jin-Wang; Yan, Jia-Wen; Catara, Vittoria; Li, Da-Zhi; Long, Gui-You; Li, Na

    2012-09-01

    Xanthomonas axonopodis pv. citri (Xac) is the causal agent of citrus bacterial canker, an economically important disease to world citrus industry. To monitor the infection process of Xac in different citrus plants, the enhanced green florescent protein (EGFP) visualizing system was constructed to visualize the propagation and localization in planta. First, the wild-type Xac was isolated from the diseased leaves of susceptible 'Bingtang' sweet orange, and then the isolated Xac was labeled with EGFP by triparental mating. After PCR identification, the growth kinetics and pathogenicity of the transformants were analyzed in comparison with the wild-type Xac. The EGFP-labeled bacteria were inoculated by spraying on the surface and infiltration in the mesophyll of 'Bingtang' sweet orange leaves. The bacterial cell multiplication and diffusion processes were observed directly under confocal laser scanning microscope at different intervals after inoculation. The results indicated that the EGFP-labeled Xac releasing clear green fluorescence light under fluorescent microscope showed the infection process and had the same pathogenicity as the wild type to citrus. Consequently, the labeled Xac demonstrated the ability as an efficient tool to monitor the pathogen infection.

  7. Field investigation of the relationship between battery size and PV system performance

    SciTech Connect

    Stevens, J.; Kratochvil, J.; Harrington, S.

    1993-07-01

    Four photovoltaic-powered lighting systems were installed in a National Forest Service campground in June of 1991. These systems have identical arrays, loads and charge controllers. The only difference was in the rated capacity of the battery bank for each system. The battery banks all use the same basic battery as a building block with the four systems utilizing either one battery, two batteries, three batteries or four batteries. The purpose of the experiment is to examine the effect of the various battery sizes on the ability of the system to charge the battery, energy available to the load, and battery lifetime. Results show an important trend in system performance concerning the impact of charge controllers on the relation between array size and battery size which results in an inability to achieve the days of battery storage originally designed for.

  8. Field investigation of the relationship between battery size and PV system performance

    SciTech Connect

    Stevens, J.; Kratochvil, J. ); Harrington, S. )

    1993-01-01

    Four photovoltaic-powered lighting systems were installed in a National Forest Service campground in June of 1991. These systems have identical arrays, loads and charge controllers. The only difference was in the rated capacity of the battery bank for each system. The battery banks all use the same basic battery as a building block with the four systems utilizing either one battery, two batteries, three batteries or four batteries. The purpose of the experiment is to examine the effect of the various battery sizes on the ability of the system to charge the battery, energy available to the load, and battery lifetime. Results show an important trend in system performance concerning the impact of charge controllers on the relation between array size and battery size which results in an inability to achieve the days of battery storage originally designed for.

  9. Field investigation of the relationship between battery size and PV system performance

    NASA Astrophysics Data System (ADS)

    Stevens, J.; Kratochvil, J.; Harrington, S.

    1993-05-01

    Four photovoltaic-powered lighting systems were installed in a National Forest Service campground in June of 1991. These systems have identical arrays, loads and charge controllers. The only difference was in the rated capacity of the battery bank for each system. The battery banks all use the same basic battery as a building block with the four systems utilizing either one battery, two batteries, three batteries or four batteries. The purpose of the experiment is to examine the effect of the various battery sizes on the ability of the system to charge the battery, energy available to the load, and battery lifetime. Results show an important trend in system performance concerning the impact of charge controllers on the relation between array size and battery size which results in an inability to achieve the days of battery storage originally designed for.

  10. Differential accumulation of Xanthomonas campestris pv. campestris proteins during the interaction with the host plant: Contributions of an in vivo system.

    PubMed

    Santos, Cristiane; Maximiano, Mariana R; Ribeiro, Daiane G; Oliveira-Neto, Osmundo B; Murad, André M; Franco, Octávio L; Mehta, Angela

    2017-06-01

    Xanthomonas campestris pv. campestris (Xcc) is the causal agent of black rot, a highly destructive disease that affects all brassicas. This work aimed to study the interaction Xcc-Brassica oleracea using an in vivo system in an attempt to identify proteins involved in pathogenicity. We used label-free shotgun 2D-nanoUPLC/MS(E) to analyze Xcc proteins in three conditions: in the interaction with susceptible (REK) and resistant (REU) plants and in culture medium (control condition). A model of Xcc-susceptible host interaction is proposed and shows that Xcc increases the abundance of several crucial proteins for infection and cell protection. In this study, we also confirmed the differential expression by qPCR analysis of selected genes. This is the first report showing a large-scale identification of proteins in an in vivo host plant condition. Considering that most studies involving phytopathogens are in vitro (growth in culture medium or in plant extract), this work contributes with relevant information related to the plant-pathogen interaction in planta. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Analysis of off-grid hybrid wind turbine/solar PV water pumping systems

    USDA-ARS?s Scientific Manuscript database

    While many remote water pumping systems exist (e.g. mechanical windmills, solar photovoltaic , wind-electric, diesel powered), very few combine both the wind and solar energy resources to possibly improve the reliability and the performance of the system. In this paper, off-grid wind turbine (WT) a...

  12. Progress & Frontiers in PV Performance

    SciTech Connect

    Deline, Chris; DiOrio, Nick; Jordan, Dirk; Toor, Fatima

    2016-09-12

    PowerPoint slides for a presentation given at Solar Power International 2016. Presentation includes System Advisor Model (SAM) introduction and battery modeling, bifacial PV modules and modeling, shade modeling and module level power electronics (MLPE), degradation rates, and PVWatts updates and validation.

  13. Hybrid Energy System Design of Micro Hydro-PV-biogas Based Micro-grid

    NASA Astrophysics Data System (ADS)

    Nishrina; Abdullah, A. G.; Risdiyanto, A.; Nandiyanto, ABD

    2017-03-01

    Hybrid renewable energy system is an arrangement of one or more sources of renewable energy and also conventional energy. This paper describes a simulation results of hybrid renewable power system based on the available potential in an educational institution in Indonesia. HOMER software was used to simulate and analyse both in terms of optimization and economic terms. This software was developed through 3 main principles; simulation, optimization, and sensitivity analysis. Generally, the presented results show that the software can demonstrate a feasible hybrid power system as well to be realized. The entire demand in case study area can be supplied by the system configuration and can be met by ¾ of electricity production. So, there are ¼ of generated energy became an excess electricity.

  14. Design and operation of grid-interactive thin-film silicon PV systems

    NASA Astrophysics Data System (ADS)

    Marion, Bill; Atmaram, Gobind; Lashway, Clin; Strachan, John W.

    Results are described from the operation of 11 thin-film amorphous silicon photovoltaic systems at three test facilities: the Florida Solar Energy Center, the New Mexico Solar Energy Institute, and Sandia National Laboratories. Commercially available modules from four US manufacturers are used in these systems, with array sizes from 133 to 750 W peak. Measured array efficiencies are from 3.1 to 4.8 percent. Except for one manufacturer, array peak power is in agreement with the calculated design ratings. For certain grid-connected systems, nonoptimal operation exists because the array peak power voltage is below the lower voltage limit of the power conditioning system. Reliability problems are found in two manufacturers' modules when shorts to ground and terminal corrosion occur. Array leakage current data are presented.

  15. Computer-Aided Modelling and Analysis of PV Systems: A Comparative Study

    PubMed Central

    Koukouvaos, Charalambos

    2014-01-01

    Modern scientific advances have enabled remarkable efficacy for photovoltaic systems with regard to the exploitation of solar energy, boosting them into having a rapidly growing position among the systems developed for the production of renewable energy. However, in many cases the design, analysis, and control of photovoltaic systems are tasks which are quite complex and thus difficult to be carried out. In order to cope with this kind of problems, appropriate software tools have been developed either as standalone products or parts of general purpose software platforms used to model and simulate the generation, transmission, and distribution of solar energy. The utilization of this kind of software tools may be extremely helpful to the successful performance evaluation of energy systems with maximum accuracy and minimum cost in time and effort. The work presented in this paper aims on a first level at the performance analysis of various configurations of photovoltaic systems through computer-aided modelling. On a second level, it provides a comparative evaluation of the credibility of two of the most advanced graphical programming environments, namely, Simulink and LabVIEW, with regard to their application in photovoltaic systems. PMID:24772007

  16. Computer-aided modelling and analysis of PV systems: a comparative study.

    PubMed

    Koukouvaos, Charalambos; Kandris, Dionisis; Samarakou, Maria

    2014-01-01

    Modern scientific advances have enabled remarkable efficacy for photovoltaic systems with regard to the exploitation of solar energy, boosting them into having a rapidly growing position among the systems developed for the production of renewable energy. However, in many cases the design, analysis, and control of photovoltaic systems are tasks which are quite complex and thus difficult to be carried out. In order to cope with this kind of problems, appropriate software tools have been developed either as standalone products or parts of general purpose software platforms used to model and simulate the generation, transmission, and distribution of solar energy. The utilization of this kind of software tools may be extremely helpful to the successful performance evaluation of energy systems with maximum accuracy and minimum cost in time and effort. The work presented in this paper aims on a first level at the performance analysis of various configurations of photovoltaic systems through computer-aided modelling. On a second level, it provides a comparative evaluation of the credibility of two of the most advanced graphical programming environments, namely, Simulink and LabVIEW, with regard to their application in photovoltaic systems.

  17. A Novel Manganese Efflux System, YebN, Is Required for Virulence by Xanthomonas oryzae pv. oryzae

    PubMed Central

    Li, Chunxia; Tao, Jun; Mao, Daqing; He, Chaozu

    2011-01-01

    Manganese ions (Mn2+) play a crucial role in virulence and protection against oxidative stress in bacterial pathogens. Such pathogens appear to have evolved complex mechanisms for regulating Mn2+ uptake and efflux. Despite numerous studies on Mn2+ uptake, however, only one efflux system has been identified to date. Here, we report on a novel Mn2+ export system, YebN, in Xanthomonas oryzae pv. oryzae (Xoo), the causative agent of bacterial leaf blight. Compared with wild-type PXO99, the yebN mutant was highly sensitive to Mn2+ and accumulated high concentrations of intracellular manganese. In addition, we found that expression of yebN was positively regulated by Mn2+ and the Mn2+-dependent transcription regulator, MntR. Interestingly, the yebN mutant was more tolerant to methyl viologen and H2O2 in low Mn2+ medium than PXO99, but more sensitive in high Mn2+ medium, implying that YebN plays an important role in Mn2+ homoeostasis and detoxification of reactive oxygen species (ROS). Notably, deletion of yebN rendered Xoo sensitive to hypo-osmotic shock, suggesting that YebN may protect against such stress. That mutation of yebN substantially reduced the Xoo growth rate and lesion formation in rice implies that YebN could be involved in Xoo fitness in host. Although YebN has two DUF204 domains, it lacks homology to any known metal transporter. Hence, this is the first report of a novel metal export system that plays essential roles in hypo-osmotic and oxidative stress, and virulence. Our results lay the foundations for elucidating the complex and fascinating relationship between metal homeostasis and host-pathogen interactions. PMID:21789199

  18. Large space systems technology, 1980, volume 1

    NASA Technical Reports Server (NTRS)

    Kopriver, F., III (Compiler)

    1981-01-01

    The technological and developmental efforts in support of the large space systems technology are described. Three major areas of interests are emphasized: (1) technology pertient to large antenna systems; (2) technology related to large space systems; and (3) activities that support both antenna and platform systems.

  19. High Resolution PV Power Modeling for Distribution Circuit Analysis

    SciTech Connect

    Norris, B. L.; Dise, J. H.

    2013-09-01

    NREL has contracted with Clean Power Research to provide 1-minute simulation datasets of PV systems located at three high penetration distribution feeders in the service territory of Southern California Edison (SCE): Porterville, Palmdale, and Fontana, California. The resulting PV simulations will be used to separately model the electrical circuits to determine the impacts of PV on circuit operations.

  20. Performance assessment of a direct-coupled PV water pumping system

    NASA Astrophysics Data System (ADS)

    Balaj, Ciprian I.; Man, Teodor E.; Paulescu, Marius

    2017-01-01

    Results of an experimental and numerical study on a water pumping system are presented in this paper. In this experiment a direct-coupled photovoltaic water pumping system, operating in real meteorological conditions, was fully monitored on the Solar Platform of the West University of Timisoara. Based on data recorded in this experiment, a numerical model for estimating the pumped water flow rate with respect to the incoming solar irradiance was developed. The model performance in relation with the solar radiative regime is assessed. The results show that that the numerical model tracks with high accuracy the measurement of daily volume of the pumped water, regardless the stability of the solar radiative regime.

  1. Feeder Voltage Regulation with High-Penetration PV Using Advanced Inverters and a Distribution Management System: A Duke Energy Case Study

    SciTech Connect

    Palmintier, Bryan; Giraldez, Julieta; Gruchalla, Kenny; Gotseff, Peter; Nagarajan, Adarsh; Harris, Tom; Bugbee, Bruce; Baggu, Murali; Gantz, Jesse; Boardman, Ethan

    2016-11-01

    Duke Energy, Alstom Grid, and the National Renewable Energy Laboratory teamed up to better understand the impacts of solar photovoltaics (PV) on distribution system operations. The core goal of the project is to compare the operational - specifically, voltage regulation - impacts of three classes of PV inverter operations: 1.) Active power only (Baseline); 2.) Local inverter control (e.g., PF...not equal...1, Q(V), etc.); and 3.) Integrated volt-VAR control (centralized through the distribution management system). These comparisons were made using multiple approaches, each of which represents an important research-and-development effort on its own: a) Quasi-steady-state time-series modeling for approximately 1 year of operations using the Alstom eTerra (DOTS) system as a simulation engine, augmented by Python scripting for scenario and time-series control and using external models for an advanced inverter; b) Power-hardware-in-the-loop (PHIL) testing of a 500-kVA-class advanced inverter and traditional voltage regulating equipment. This PHIL testing used cosimulation to link full-scale feeder simulation using DOTS in real time to hardware testing; c) Advanced visualization to provide improved insights into time-series results and other PV operational impacts; and d) Cost-benefit analysis to compare the financial and business-model impacts of each integration approach.

  2. Building a Firm Foundation: Recommendations for New York City's Job Training System. P/PV Briefs.

    ERIC Educational Resources Information Center

    Buck, Maria L.

    This report describes the performance of New York City's Job Training Partnership Act (JTPA) adult training providers. It discusses challenges currently faced by providers, and recommends strategies for improving the performance of the city's employment and training system, including those arising from the implementation of the Workforce…

  3. Hybrid PV/Wind Power Systems Incorporating Battery Storage and Considering the Stochastic Nature of Renewable Resources

    NASA Astrophysics Data System (ADS)

    Barnawi, Abdulwasa Bakr

    Hybrid power generation system and distributed generation technology are attracting more investments due to the growing demand for energy nowadays and the increasing awareness regarding emissions and their environmental impacts such as global warming and pollution. The price fluctuation of crude oil is an additional reason for the leading oil producing countries to consider renewable resources as an alternative. Saudi Arabia as the top oil exporter country in the word announced the "Saudi Arabia Vision 2030" which is targeting to generate 9.5 GW of electricity from renewable resources. Two of the most promising renewable technologies are wind turbines (WT) and photovoltaic cells (PV). The integration or hybridization of photovoltaics and wind turbines with battery storage leads to higher adequacy and redundancy for both autonomous and grid connected systems. This study presents a method for optimal generation unit planning by installing a proper number of solar cells, wind turbines, and batteries in such a way that the net present value (NPV) is minimized while the overall system redundancy and adequacy is maximized. A new renewable fraction technique (RFT) is used to perform the generation unit planning. RFT was tested and validated with particle swarm optimization and HOMER Pro under the same conditions and environment. Renewable resources and load randomness and uncertainties are considered. Both autonomous and grid-connected system designs were adopted in the optimal generation units planning process. An uncertainty factor was designed and incorporated in both autonomous and grid connected system designs. In the autonomous hybrid system design model, the strategy including an additional amount of operation reserve as a percent of the hourly load was considered to deal with resource uncertainty since the battery storage system is the only backup. While in the grid-connected hybrid system design model, demand response was incorporated to overcome the impact of

  4. [Establishment of the hrp-inducing systems for the expression of the hrp genes of Xanthomonas oryzae pv. oryzicola].

    PubMed

    Xiao, You-lun; Li, Yu-rong; Liu, Zhi-yang; Xiang, Yong; Chen, Gong-you

    2007-06-01

    The hrp genes of Xanthomonas oryzae pv. oryzicola (Xooc), which is the causal agent of bacterial leaf streak in rice, possesses the ability to elicit hypersensitive response on nonhost plants and the pathogenicity in host rice. In order to analyze the function of the hrp genes, we developed hrp-inducing systems using transcriptional hrp: :gfp fusions with the promoters of hrpX and hpa 1 of Xooc. The levels of GFP protein expression indicated that the hrp gene expression in Xooc was not efficiently induced in NB medium, but efficiently in XOM3 medium. Using the hrpG and hrpX mutants of Xooc as the controls, the results by RT-PCR demonstrated that in wild type strain the expression of the hpa1 gene was suppressed in NB medium, but was increased in XOM3 medium. When incubated in XOM3, the expression of the hpa1 gene was abolished in hrpX mutant, while the level of the hpa1 gene expression was lower in the hrpG mutant than that in wild-type strain. More importantly, it was found that the induction of the hrp gene expression was strongly increased in response to rice suspension cells and callus in this study. This suggests that the hrp-inducing systems, XOM3 or rice suspension cells or rice callus, for the induction of the hrp genes expression be useful for functionally analyzing the hrp genes, mining effectors secreted by the type III secretion apparatus and understanding pathogenicity determinats of Xooc.

  5. Design and development of a laminated Fresnel lens for point focus pv systems

    SciTech Connect

    Hobbs, R.B. Jr.

    1981-01-01

    The design and fabrication of a laminated Fresnel lens for point focus photovoltaic concentrators systems is described. The lens consists of a glass superstrate to which a thin 6.7 inch square Fresnel lens is bonded. A key aim of the program was to investigate the technical feasibility of injection molding acceptable quality Fresnel lenses. Significant progress was made in demonstrating this feasibility and is reported.

  6. Large Space Antenna Systems Technology, 1984

    NASA Technical Reports Server (NTRS)

    Boyer, W. J. (Compiler)

    1985-01-01

    Papers are presented which provide a comprehensive review of space missions requiring large antenna systems and of the status of key technologies required to enable these missions. Topic areas include mission applications for large space antenna systems, large space antenna structural systems, materials and structures technology, structural dynamics and control technology, electromagnetics technology, large space antenna systems and the space station, and flight test and evaluation.

  7. Islanding detection technique using wavelet energy in grid-connected PV system

    NASA Astrophysics Data System (ADS)

    Kim, Il Song

    2016-08-01

    This paper proposes a new islanding detection method using wavelet energy in a grid-connected photovoltaic system. The method detects spectral changes in the higher-frequency components of the point of common coupling voltage and obtains wavelet coefficients by multilevel wavelet analysis. The autocorrelation of the wavelet coefficients can clearly identify islanding detection, even in the variations of the grid voltage harmonics during normal operating conditions. The advantage of the proposed method is that it can detect islanding condition the conventional under voltage/over voltage/under frequency/over frequency methods fail to detect. The theoretical method to obtain wavelet energies is evolved and verified by the experimental result.

  8. Transcription Factors PvERF15 and PvMTF-1 Form a Cadmium Stress Transcriptional Pathway1[OPEN

    PubMed Central

    Lin, Tingting; Yang, Wanning; Lu, Wen; Wang, Ying

    2017-01-01

    In plants, cadmium (Cd)-responsive transcription factors are key downstream effectors of Cd stress transcriptional pathways, which are capable of converging Cd stress signals through triggering the expression of Cd detoxification genes. However, the upstream transcriptional regulatory pathways that modulate their responses to Cd are less clear. Previously, we identified the bean (Phaseolus vulgaris) METAL RESPONSE ELEMENT-BINDING TRANSCRIPTION FACTOR1 (PvMTF-1) that responds to Cd and confers Cd tolerance in planta. Here, we demonstrate an upstream transcriptional regulation of the PvMTF-1 response to Cd. Using a yeast one-hybrid system, we cloned the bean ETHYLENE RESPONSE FACTOR15 (PvERF15) that binds to the PvMTF-1 promoter. PvERF15 was strongly induced by Cd stress, and its overexpression resulted in the up-regulation of PvMTF-1. DNA-protein interaction assays further revealed that PvERF15 binds directly to a 19-bp AC-rich element in the PvMTF-1 promoter. The AC-rich element serves as a positive element bound by PvERF15 to activate gene expression. More importantly, knockdown of PvERF15 by RNA interference resulted in reduced Cd-induced expression of PvMTF-1. PvERF15 seems to be involved in Cd tolerance, since knockdown of PvERF15 by RNA interference in bean leaf discs decreased Cd tolerance in a transient assay. Since PvERF15 is a component of the Cd stress transcriptional pathway in beans and PvMTF-1 is one of its downstream targets, our findings provide a PvERF15/PvMTF-1 transcriptional pathway and thereby contribute to the understanding of Cd stress transcriptional regulatory pathways in plants. PMID:28073984

  9. Analysis of large power systems

    NASA Technical Reports Server (NTRS)

    Dommel, H. W.

    1975-01-01

    Computer-oriented power systems analysis procedures in the electric utilities are surveyed. The growth of electric power systems is discussed along with the solution of sparse network equations, power flow, and stability studies.

  10. Large Space Systems Technology, Part 2, 1981

    NASA Technical Reports Server (NTRS)

    Boyer, W. J. (Compiler)

    1982-01-01

    Four major areas of interest are covered: technology pertinent to large antenna systems; technology related to the control of large space systems; basic technology concerning structures, materials, and analyses; and flight technology experiments. Large antenna systems and flight technology experiments are described. Design studies, structural testing results, and theoretical applications are presented with accompanying validation data. These research studies represent state-of-the art technology that is necessary for the development of large space systems. A total systems approach including structures, analyses, controls, and antennas is presented as a cohesive, programmatic plan for large space systems.

  11. Real-time Series Resistance Monitoring in PV Systems; NREL (National Renewable Energy Laboratory)

    SciTech Connect

    Deceglie, M. G.; Silverman, T. J.; Marion, B.; Kurtz, S. R.

    2015-06-14

    We apply the physical principles of a familiar method, suns-Voc, to a new application: the real-time detection of series resistance changes in modules and systems operating outside. The real-time series resistance (RTSR) method that we describe avoids the need for collecting IV curves or constructing full series-resistance-free IV curves. RTSR is most readily deployable at the module level on apply the physical principles of a familiar method, suns-Voc, to a new application: the real-time detection of series resistance changes in modules and systems operating outside. The real-time series resistance (RTSR) method that we describe avoids the need for collecting IV curves or constructing full series-resistance-free IV curves. RTSR is most readily deployable at the module level on micro-inverters or module-integrated electronics, but it can also be extended to full strings. Automated detection of series resistance increases can provide early warnings of some of the most common reliability issues, which also pose fire risks, including broken ribbons, broken solder bonds, and contact problems in the junction or combiner box. We describe the method in detail and describe a sample application to data collected from modules operating in the field.

  12. Nationwide Analysis of U.S. Commercial Building Solar Photovoltaic (PV) Breakeven Conditions

    SciTech Connect

    Davidson, Carolyn; Gagnon, Pieter; Denholm, Paul; Margolis, Robert

    2015-10-01

    The commercial sector offers strong potential for solar photovoltaics (PV) owing to abundant available roof space suitable for PV and the opportunity to offset the sector's substantial retail electricity purchases. This report evaluated the breakeven price of PV for 15 different building types and various financing options by calculating electricity savings based on detailed rate structures for most U.S. utility territories (representing approximately two thirds of U.S. commercial customers). We find that at current capital costs, an estimated 1/3 of U.S. commercial customers break even in the cash scenario and approximately 2/3 break even in the loan scenario. Variation in retail rates is a stronger driver of breakeven prices than is variation in building load or solar generation profiles. At the building level, variation in the average breakeven price is largely driven by the ability for a PV system to reduce demand charges.

  13. Evolution of integrated panel structural design and interfaces for PV power plants

    NASA Technical Reports Server (NTRS)

    Arnett, J. C.; Anderson, A. J.; Robertson, R. E.

    1983-01-01

    The evolution of integrated photovoltaic (PV) panel design at ARCO Solar is discussed. Historically, framed PV modules of about 1 x 4-ft size were individually mounted in the field on fixed support structures and interconnected electrically with cables to build higher-power arrays. When ARCO Solar saw the opportunity in 1982 to marry its PV modules with state-of-the-art heliostat trackers developed by ARCO Power Systems, it became obvious that mounting individual modules was impractical. For this project, the framed modules were factory-assembled into panels and interconnected with cables before being mounted on the trackers. Since then, ARCO Solar made considerable progress and gained substantial experience in the design and fabrication of large PV panels. Constraints and criteria considered in these design activities included static and dynamic loads; assembly and transportation equipment and logistics, structural and electrical interfaces, and safety and grounding concerns.

  14. Evolution of integrated panel structural design and interfaces for PV power plants

    NASA Technical Reports Server (NTRS)

    Arnett, J. C.; Anderson, A. J.; Robertson, R. E.

    1983-01-01

    The evolution of integrated photovoltaic (PV) panel design at ARCO Solar is discussed. Historically, framed PV modules of about 1 x 4-ft size were individually mounted in the field on fixed support structures and interconnected electrically with cables to build higher-power arrays. When ARCO Solar saw the opportunity in 1982 to marry its PV modules with state-of-the-art heliostat trackers developed by ARCO Power Systems, it became obvious that mounting individual modules was impractical. For this project, the framed modules were factory-assembled into panels and interconnected with cables before being mounted on the trackers. Since then, ARCO Solar made considerable progress and gained substantial experience in the design and fabrication of large PV panels. Constraints and criteria considered in these design activities included static and dynamic loads; assembly and transportation equipment and logistics, structural and electrical interfaces, and safety and grounding concerns.

  15. Evolution of integrated panel structural design and interfaces for PV power plants

    NASA Astrophysics Data System (ADS)

    Arnett, J. C.; Anderson, A. J.; Robertson, R. E.

    1983-11-01

    The evolution of integrated photovoltaic (PV) panel design at ARCO Solar is discussed. Historically, framed PV modules of about 1 x 4-ft size were individually mounted in the field on fixed support structures and interconnected electrically with cables to build higher-power arrays. When ARCO Solar saw the opportunity in 1982 to marry its PV modules with state-of-the-art heliostat trackers developed by ARCO Power Systems, it became obvious that mounting individual modules was impractical. For this project, the framed modules were factory-assembled into panels and interconnected with cables before being mounted on the trackers. Since then, ARCO Solar made considerable progress and gained substantial experience in the design and fabrication of large PV panels. Constraints and criteria considered in these design activities included static and dynamic loads; assembly and transportation equipment and logistics, structural and electrical interfaces, and safety and grounding concerns.

  16. The ColRS system of Xanthomonas oryzae pv. oryzae is required for virulence and growth in iron-limiting conditions.

    PubMed

    Subramoni, Sujatha; Pandey, Alok; Vishnu Priya, M R; Patel, Hitendra Kumar; Sonti, Ramesh V

    2012-09-01

    Xanthomonas oryzae pv. oryzae, the causal agent of bacterial blight of rice, produces siderophores only under iron-limiting conditions. We screened 15 400 mTn5-induced mutants of X. oryzae pv. oryzae and isolated 27 mutants that produced siderophores even under iron-replete conditions. We found that the mTn5 insertions in 25 of these mutants were in or close to six genes. Mutants with insertions in five of these genes [colS, XOO1806 (a conserved hypothetical protein), acnB, prpR and prpB] exhibited a deficiency for growth on iron-limiting medium and a decrease in virulence. Insertions in a sixth gene, XOO0007 (a conserved hypothetical protein), were found to affect the ability to grow on iron-limiting medium, but did not affect the virulence. Targeted gene disruptants for colR (encoding the predicted cognate regulatory protein for ColS) also exhibited a deficiency for growth on iron-limiting medium and a decrease in virulence. colR and colS mutants were defective in the elicitation of hypersensitive response symptoms on the nonhost tomato. In addition, colR and colS mutants induced a rice basal defence response, suggesting that they are compromised in the suppression of host innate immunity. Quantitative reverse transcription-polymerase chain reaction (RT-PCR) analysis demonstrated that a functional ColRS system is required for the optimal expression of several genes encoding components of the type 3 secretion system (T3SS) of X. oryzae pv. oryzae. Our results demonstrate the role of several novel genes, including colR/colS, in the promotion of growth on iron-limiting medium and the virulence of X. oryzae pv. oryzae.

  17. Real-Time Series Resistance Monitoring in PV Systems Without the Need for IV Curves

    SciTech Connect

    Deceglie, Michael G.; Silverman, Timothy J.; Marion, Bill; Kurtz, Sarah R.

    2015-06-14

    We apply the physical principles of a familiar method, suns-Voc, to a new application: the real-time detection of series resistance changes in modules and systems operating outside. The real-time series resistance (RTSR) method that we describe avoids the need for collecting IV curves or constructing full series-resistance-free IV curves. RTSR is most readily deployable at the module level on micro-inverters or module-integrated electronics, but it can also be extended to full strings. Automated detection of series resistance increases can provide early warnings of some of the most common reliability issues, which also pose fire risks, including broken ribbons, broken solder bonds, and contact problems in the junction or combiner box. We describe the method in detail and describe a sample application to data collected from modules operating in the field.

  18. Updated Proposal for a Guide for Quality Management Systems for PV Manufacturing. Supplemental Requirements to ISO 9001-2008

    SciTech Connect

    Ramu, Govind; Yamamichi, Masaaki; Zhou, Wei; Mikonowicz, Alex; Lokanath, Sumanth; Eguchi, Yoshihito; Norum, Paul; Kurtz, Sarah

    2015-03-01

    The goal of this Technical Specification is to provide a guideline for manufacturers of photovoltaic (PV) modules to produce modules that, once the design is proven to meet the quality and reliability requirements, replicate the design on an industrial scale without compromising its consistency with the requirements.

  19. National Energy with Weather System Simultator (NEWS) Sets Bounds on Cost Effective Wind and Solar PV Deployment in the USA without the Use of Storage.

    NASA Astrophysics Data System (ADS)

    Clack, C.; MacDonald, A. E.; Alexander, A.; Dunbar, A. D.; Xie, Y.; Wilczak, J. M.

    2014-12-01

    The importance of weather-driven renewable energies for the United States energy portfolio is growing. The main perceived problems with weather-driven renewable energies are their intermittent nature, low power density, and high costs. In 2009, we began a large-scale investigation into the characteristics of weather-driven renewables. The project utilized the best available weather data assimilation model to compute high spatial and temporal resolution power datasets for the renewable resources of wind and solar PV. The weather model used is the Rapid Update Cycle for the years of 2006-2008. The team also collated a detailed electrical load dataset for the contiguous USA from the Federal Energy Regulatory Commission for the same three-year period. The coincident time series of electrical load and weather data allows the possibility of temporally correlated computations for optimal design over large geographic areas. The past two years have seen the development of a cost optimization mathematic model that designs electric power systems. The model plans the system and dispatches it on an hourly timescale. The system is designed to be reliable, reduce carbon, reduce variability of renewable resources and move the electricity about the whole domain. The system built would create the infrastructure needed to reduce carbon emissions to 0 by 2050. The advantages of the system is reduced water demain, dual incomes for farmers, jobs for construction of the infrastructure, and price stability for energy. One important simplified test that was run included existing US carbon free power sources, natural gas power when needed, and a High Voltage Direct Current power transmission network. This study shows that the costs and carbon emissions from an optimally designed national system decrease with geographic size. It shows that with achievable estimates of wind and solar generation costs, that the US could decrease its carbon emissions by up to 80% by the early 2030s, without an

  20. Energy and economic assessment of desiccant cooling systems coupled with single glazed air and hybrid PV/thermal solar collectors for applications in hot and humid climate

    SciTech Connect

    Beccali, Marco; Finocchiaro, Pietro; Nocke, Bettina

    2009-10-15

    This paper presents a detailed analysis of the energy and economic performance of desiccant cooling systems (DEC) equipped with both single glazed standard air and hybrid photovoltaic/thermal (PV/t) collectors for applications in hot and humid climates. The use of 'solar cogeneration' by means of PV/t hybrid collectors enables the simultaneous production of electricity and heat, which can be directly used by desiccant air handling units, thereby making it possible to achieve very energy savings. The present work shows the results of detailed simulations conducted for a set of desiccant cooling systems operating without any heat storage. System performance was investigated through hourly simulations for different systems and load combinations. Three configurations of DEC systems were considered: standard DEC, DEC with an integrated heat pump and DEC with an enthalpy wheel. Two kinds of building occupations were considered: office and lecture room. Moreover, three configurations of solar-assisted air handling units (AHU) equipped with desiccant wheels were considered and compared with standard AHUs, focusing on achievable primary energy savings. The relationship between the solar collector's area and the specific primary energy consumption for different system configurations and building occupation patterns is described. For both occupation patterns, sensitivity analysis on system performance was performed for different solar collector areas. Also, this work presents an economic assessment of the systems. The cost of conserved energy and the payback time were calculated, with and without public incentives for solar cooling systems. It is worth noting that the use of photovoltaics, and thus the exploitation of related available incentives in many European countries, could positively influence the spread of solar air cooling technologies (SAC). An outcome of this work is that SAC systems equipped with PV/t collectors are shown to have better performance in terms of

  1. PV_LIB Toolbox v. 1.3

    SciTech Connect

    2015-12-09

    PV_LIB comprises a library of Matlab? code for modeling photovoltaic (PV) systems. Included are functions to compute solar position and to estimate irradiance in the PV system’s plane of array, cell temperature, PV module electrical output, and conversion from DC to AC power. Also included are functions that aid in determining parameters for module performance models from module characterization testing. PV_LIB is open source code primarily intended for research and academic purposes. All algorithms are documented in openly available literature with the appropriate references included in comments within the code.

  2. Survey on large scale system control methods

    NASA Technical Reports Server (NTRS)

    Mercadal, Mathieu

    1987-01-01

    The problem inherent to large scale systems such as power network, communication network and economic or ecological systems were studied. The increase in size and flexibility of future spacecraft has put those dynamical systems into the category of large scale systems, and tools specific to the class of large systems are being sought to design control systems that can guarantee more stability and better performance. Among several survey papers, reference was found to a thorough investigation on decentralized control methods. Especially helpful was the classification made of the different existing approaches to deal with large scale systems. A very similar classification is used, even though the papers surveyed are somehow different from the ones reviewed in other papers. Special attention is brought to the applicability of the existing methods to controlling large mechanical systems like large space structures. Some recent developments are added to this survey.

  3. Heritage Park Facilities PV Project

    SciTech Connect

    Hobaica, Mark

    2013-09-26

    Project Objective: To procure a photovoltaic array (PV) system which will generate approximately 256kW of power to be used for the operations of the Aquatic Complex and the adjacent Senior Facility at the Heritage Park. This project complies with the EERE’s work and objectives by promoting the development and deployment of an energy system that will provide current and future generations with clean, efficient, affordable, and reliable energy.

  4. Energy balance of the global photovoltaic (PV) industry--is the PV industry a net electricity producer?

    PubMed

    Dale, Michael; Benson, Sally M

    2013-04-02

    A combination of declining costs and policy measures motivated by greenhouse gas (GHG) emissions reduction and energy security have driven rapid growth in the global installed capacity of solar photovoltaics (PV). This paper develops a number of unique data sets, namely the following: calculation of distribution of global capacity factor for PV deployment; meta-analysis of energy consumption in PV system manufacture and deployment; and documentation of reduction in energetic costs of PV system production. These data are used as input into a new net energy analysis of the global PV industry, as opposed to device level analysis. In addition, the paper introduces a new concept: a model tracking energetic costs of manufacturing and installing PV systems, including balance of system (BOS) components. The model is used to forecast electrical energy requirements to scale up the PV industry and determine the electricity balance of the global PV industry to 2020. Results suggest that the industry was a net consumer of electricity as recently as 2010. However, there is a >50% that in 2012 the PV industry is a net electricity provider and will "pay back" the electrical energy required for its early growth before 2020. Further reducing energetic costs of PV deployment will enable more rapid growth of the PV industry. There is also great potential to increase the capacity factor of PV deployment. These conclusions have a number of implications for R&D and deployment, including the following: monitoring of the energy embodied within PV systems; designing more efficient and durable systems; and deploying PV systems in locations that will achieve high capacity factors.

  5. Improvements of hybrid PV-T solar energy systems using Amlouk-Boubaker optothermal expansivity optimizing abacus sketch

    SciTech Connect

    Boubaker, K.; Amlouk, M.

    2010-10-15

    This study is a prelude to the definition of a new synthetic parameter inserted in a 2D abacus. This parameter: the Amlouk-Boubaker optothermal expansivity <{psi}{sub AB}>, is defined, for a given PV-T material, as a thermal diffusivity-to-optical effective absorptivity ratio. This parameter's unit evokes a heat flow velocity inside the material. Consequently, the parameter {psi}{sub AB} could be combined with the already known bandgap energy E{sub g}, in order to establish a 2D abacus. A sketched scheme of the 2D abacus is proposed as a guide for investigation and evaluation of PV-T candidate materials like metal oxides, amorphous silicon, zinc-doped binary compounds, and hydrogenated amorphous carbon. Using this abacus, designers will be able to compare solar energy-related materials on the basis of conjoint optical and thermal efficiency. (author)

  6. Virulence and in planta movement of Xanthomonas hortorum pv. pelargonii are affected by the diffusible signal factor (DSF)-dependent quorum sensing system.

    PubMed

    Barel, Victoria; Chalupowicz, Laura; Barash, Isaac; Sharabani, Galit; Reuven, Michal; Dror, Orit; Burdman, Saul; Manulis-Sasson, Shulamit

    2015-09-01

    Xanthomonas hortorum pv. pelargonii (Xhp), the causal agent of bacterial blight in pelargonium, is the most threatening bacterial disease of this ornamental worldwide. To gain an insight into the regulation of virulence in Xhp, we have disrupted the quorum sensing (QS) genes, which mediate the biosynthesis and sensing of the diffusible signal factor (DSF). Mutations in rpfF (encoding the DSF synthase) and rpfC (encoding the histidine sensor kinase of the two-component system RfpC/RpfG) and overexpression of rpfF showed a significant reduction in incidence and severity of the disease on pelargonium. Confocal laser scanning microscopy images of inoculated plants with a green fluorescent protein (GFP)-labelled wild-type strain showed that the pathogen is homogeneously dispersed in the lumen of xylem vessels, reaching the apex and invading the intercellular spaces of the leaf mesophyll tissue within 21 days. In contrast, the rpfF and rpfC knockout mutants, as well as the rpfF-overexpressing strain, remained confined to the vicinity of the inoculation site. The rpfF and rpfC mutants formed large incoherent aggregates in the xylem vessels that might interfere with upward movement of the bacterium within the plant. Both mutants also formed extended aggregates under in vitro conditions, whereas the wild-type strain formed microcolonies. Expression levels of putative virulence genes in planta were substantially reduced within 48 h after inoculation with the QS mutants when compared with the wild-type. The results presented indicate that an optimal DSF concentration is crucial for successful colonization and virulence of Xhp in pelargonium. © 2014 BSPP AND JOHN WILEY & SONS LTD.

  7. Large inflated-antenna system

    NASA Technical Reports Server (NTRS)

    Hinson, W. F.; Keafer, L. S.

    1984-01-01

    It is proposed that for inflatable antenna systems, technology feasibility can be demonstrated and parametric design and scalability (scale factor 10 to 20) can be validated with an experiment using a 16-m-diameter antenna attached to the Shuttle. The antenna configuration consists of a thin film cone and paraboloid held to proper shape by internal pressure and a self-rigidizing torus. The cone and paraboloid would be made using pie-shaped gores with the paraboloid being coated with aluminum to provide reflectivity. The torus would be constructed using an aluminum polyester composite that when inflated would erect to a smooth shell that can withstand loads without internal pressure.

  8. GridPV Toolbox

    SciTech Connect

    Broderick, Robert; Quiroz, Jimmy; Grijalva, Santiago; Reno, Matthew; Coogan, Kyle

    2014-07-15

    Matlab Toolbox for simulating the impact of solar energy on the distribution grid. The majority of the functions are useful for interfacing OpenDSS and MATLAB, and they are of generic use for commanding OpenDSS from MATLAB and retrieving GridPV Toolbox information from simulations. A set of functions is also included for modeling PV plant output and setting up the PV plant in the OpenDSS simulation. The toolbox contains functions for modeling the OpenDSS distribution feeder on satellite images with GPS coordinates. Finally, example simulations functions are included to show potential uses of the toolbox functions.

  9. Induced systemic resistance in Arabidopsis thaliana against Pseudomonas syringae pv. tomato by 2,4-diacetylphloroglucinol-producing Pseudomonas fluorescens.

    PubMed

    Weller, David M; Mavrodi, Dmitri V; van Pelt, Johan A; Pieterse, Corné M J; van Loon, Leendert C; Bakker, Peter A H M

    2012-04-01

    Pseudomonas fluorescens strains that produce the polyketide antibiotic 2,4-diacetylphloroglucinol (2,4-DAPG) are among the most effective rhizobacteria that suppress root and crown rots, wilts, and damping-off diseases of a variety of crops, and they play a key role in the natural suppressiveness of some soils to certain soilborne pathogens. Root colonization by 2,4-DAPG-producing P. fluorescens strains Pf-5 (genotype A), Q2-87 (genotype B), Q8r1-96 (genotype D), and HT5-1 (genotype N) produced induced systemic resistance (ISR) in Arabidopsis thaliana accession Col-0 against bacterial speck caused by P. syringae pv. tomato. The ISR-eliciting activity of the four bacterial genotypes was similar, and all genotypes were equivalent in activity to the well-characterized strain P. fluorescens WCS417r. The 2,4-DAPG biosynthetic locus consists of the genes phlHGF and phlACBDE. phlD or phlBC mutants of Q2-87 (2,4-DAPG minus) were significantly reduced in ISR activity, and genetic complementation of the mutants restored ISR activity back to wild-type levels. A phlF regulatory mutant (overproducer of 2,4-DAPG) had ISR activity equivalent to the wild-type Q2-87. Introduction of DAPG into soil at concentrations of 10 to 250 μM 4 days before challenge inoculation induced resistance equivalent to or better than the bacteria. Strain Q2-87 induced resistance on transgenic NahG plants but not on npr1-1, jar1, and etr1 Arabidopsis mutants. These results indicate that the antibiotic 2,4-DAPG is a major determinant of ISR in 2,4-DAPG-producing P. fluorescens, that the genotype of the strain does not affect its ISR activity, and that the activity induced by these bacteria operates through the ethylene- and jasmonic acid-dependent signal transduction pathway.

  10. Comparative density of CCK- and PV-GABA cells within the cortex and hippocampus

    PubMed Central

    Whissell, Paul D.; Cajanding, Janine D.; Fogel, Nicole; Kim, Jun Chul

    2015-01-01

    Cholecystokinin (CCK)- and parvalbumin (PV)-expressing neurons constitute the two major populations of perisomatic GABAergic neurons in the cortex and the hippocampus. As CCK- and PV-GABA neurons differ in an array of morphological, biochemical and electrophysiological features, it has been proposed that they form distinct inhibitory ensembles which differentially contribute to network oscillations and behavior. However, the relationship and balance between CCK- and PV-GABA neurons in the inhibitory networks of the brain is currently unclear as the distribution of these cells has never been compared on a large scale. Here, we systemically investigated the distribution of CCK- and PV-GABA cells across a wide number of discrete forebrain regions using an intersectional genetic approach. Our analysis revealed several novel trends in the distribution of these cells. While PV-GABA cells were more abundant overall, CCK-GABA cells outnumbered PV-GABA cells in several subregions of the hippocampus, medial prefrontal cortex and ventrolateral temporal cortex. Interestingly, CCK-GABA cells were relatively more abundant in secondary/association areas of the cortex (V2, S2, M2, and AudD/AudV) than they were in corresponding primary areas (V1, S1, M1, and Aud1). The reverse trend was observed for PV-GABA cells. Our findings suggest that the balance between CCK- and PV-GABA cells in a given cortical region is related to the type of processing that area performs; inhibitory networks in the secondary cortex tend to favor the inclusion of CCK-GABA cells more than networks in the primary cortex. The intersectional genetic labeling approach employed in the current study expands upon the ability to study molecularly defined subsets of GABAergic neurons. This technique can be applied to the investigation of neuropathologies which involve disruptions to the GABAergic system, including schizophrenia, stress, maternal immune activation and autism. PMID:26441554

  11. Updating Technical Screens for PV Interconnection: Preprint

    SciTech Connect

    Coddington, M.; Ellis, A.; Lynn, K.; Razon, A.; Key, T.; Kroposki, B.; Mather, B.; Hill, R.; Nicole, K.; Smith, J.

    2012-08-01

    Solar photovoltaics (PV) is the dominant type of distributed generation (DG) technology interconnected to electric distribution systems in the United States, and deployment of PV systems continues to increase rapidly. Considering the rapid growth and widespread deployment of PV systems in United States electric distribution grids, it is important that interconnection procedures be as streamlined as possible to avoid unnecessary interconnection studies, costs, and delays. Because many PV interconnection applications involve high penetration scenarios, the process needs to allow for a sufficiently rigorous technical evaluation to identify and address possible system impacts. Existing interconnection procedures are designed to balance the need for efficiency and technical rigor for all DG. However, there is an implicit expectation that those procedures will be updated over time in order to remain relevant with respect to evolving standards, technology, and practical experience. Modifications to interconnection screens and procedures must focus on maintaining or improving safety and reliability, as well as accurately allocating costs and improving expediency of the interconnection process. This paper evaluates the origins and usefulness of the capacity penetration screen, offers potential short-term solutions which could effectively allow fast-track interconnection to many PV system applications, and considers longer-term solutions for increasing PV deployment levels in a safe and reliable manner while reducing or eliminating the emphasis on the penetration screen.

  12. Large thermal protection system panel

    NASA Technical Reports Server (NTRS)

    Myers, Franklin K. (Inventor); Weinberg, David J. (Inventor); Tran, Tu T. (Inventor)

    2003-01-01

    A protective panel for a reusable launch vehicle provides enhanced moisture protection, simplified maintenance, and increased temperature resistance. The protective panel includes an outer ceramic matrix composite (CMC) panel, and an insulative bag assembly coupled to the outer CMC panel for isolating the launch vehicle from elevated temperatures and moisture. A standoff attachment system attaches the outer CMC panel and the bag assembly to the primary structure of the launch vehicle. The insulative bag assembly includes a foil bag having a first opening shrink fitted to the outer CMC panel such that the first opening and the outer CMC panel form a water tight seal at temperatures below a desired temperature threshold. Fibrous insulation is contained within the foil bag for protecting the launch vehicle from elevated temperatures. The insulative bag assembly further includes a back panel coupled to a second opening of the foil bag such that the fibrous insulation is encapsulated by the back panel, the foil bag, and the outer CMC panel. The use of a CMC material for the outer panel in conjunction with the insulative bag assembly eliminates the need for waterproofing processes, and ultimately allows for more efficient reentry profiles.

  13. Grid Integrated Distributed PV (GridPV) Version 2.

    SciTech Connect

    Reno, Matthew J.; Coogan, Kyle

    2014-12-01

    This manual provides the documentation of the MATLAB toolbox of functions for using OpenDSS to simulate the impact of solar energy on the distribution system. The majority of the functio ns are useful for interfacing OpenDSS and MATLAB, and they are of generic use for commanding OpenDSS from MATLAB and retrieving information from simulations. A set of functions is also included for modeling PV plant output and setting up the PV plant in th e OpenDSS simulation. The toolbox contains functions for modeling the OpenDSS distribution feeder on satellite images with GPS coordinates. Finally, example simulations functions are included to show potential uses of the toolbox functions. Each function i n the toolbox is documented with the function use syntax, full description, function input list, function output list, example use, and example output.

  14. S4(13)-PV cell-penetrating peptide induces physical and morphological changes in membrane-mimetic lipid systems and cell membranes: implications for cell internalization.

    PubMed

    Cardoso, Ana M S; Trabulo, Sara; Cardoso, Ana L; Lorents, Annely; Morais, Catarina M; Gomes, Paula; Nunes, Cláudia; Lúcio, Marlene; Reis, Salette; Padari, Kärt; Pooga, Margus; Pedroso de Lima, Maria C; Jurado, Amália S

    2012-03-01

    The present work aims to gain insights into the role of peptide-lipid interactions in the mechanisms of cellular internalization and endosomal escape of the S4(13)-PV cell-penetrating peptide, which has been successfully used in our laboratory as a nucleic acid delivery system. A S4(13)-PV analogue, S4(13)-PVscr, displaying a scrambled amino acid sequence, deficient cell internalization and drug delivery inability, was used in this study for comparative purposes. Differential scanning calorimetry, fluorescence polarization and X-ray diffraction at small and wide angles techniques showed that both peptides interacted with anionic membranes composed of phosphatidylglycerol or a mixture of this lipid with phosphatidylethanolamine, increasing the lipid order, shifting the phase transition to higher temperatures and raising the correlation length between the bilayers. However, S4(13)-PVscr, in contrast to the wild-type peptide, did not promote lipid domain segregation and induced the formation of an inverted hexagonal lipid phase instead of a cubic phase in the lipid systems assayed. Electron microscopy showed that, as opposed to S4(13)-PVscr, the wild-type peptide induced the formation of a non-lamellar organization in membranes of HeLa cells. We concluded that lateral phase separation and destabilization of membrane lamellar structure without compromising membrane integrity are on the basis of the lipid-driven and receptor-independent mechanism of cell entry of S4(13)-PV peptide. Overall, our results can contribute to a better understanding of the role of peptide-lipid interactions in the mechanisms of cell-penetrating peptide membrane translocation, helping in the future design of more efficient cell-penetrating peptide-based drug delivery systems.

  15. Large Space Antenna Systems Technology, part 1

    NASA Technical Reports Server (NTRS)

    Lightner, E. B. (Compiler)

    1983-01-01

    A compilation of the unclassified papers presented at the NASA Conference on Large Space Antenna Systems Technology covers the following areas: systems, structures technology, control technology, electromagnetics, and space flight test and evaluation.

  16. Improved Large-Field Focusing Schlieren System

    NASA Technical Reports Server (NTRS)

    Weinstein, Leonard M.

    1993-01-01

    System used to examine complicated two- and three-dimensional flows. High-brightness large-field focusing schlieren system incorporates Fresnel lens instead of glass diffuser. In system with large field of view, image may also be very large. Relay optical subsystem minifies large image while retaining all of light. Facilities candidates for use of focusing schlieren include low-speed wind and water tunnels. Heated or cooled flow tracers or injected low- or high-density tracers used to make flows visible for photographic recording.

  17. Automating large-scale reactor systems

    SciTech Connect

    Kisner, R.A.

    1985-01-01

    This paper conveys a philosophy for developing automated large-scale control systems that behave in an integrated, intelligent, flexible manner. Methods for operating large-scale systems under varying degrees of equipment degradation are discussed, and a design approach that separates the effort into phases is suggested. 5 refs., 1 fig.

  18. Scalable Optimization Methods for Distribution Networks With High PV Integration

    SciTech Connect

    Guggilam, Swaroop S.; Dall'Anese, Emiliano; Chen, Yu Christine; Dhople, Sairaj V.; Giannakis, Georgios B.

    2016-07-01

    This paper proposes a suite of algorithms to determine the active- and reactive-power setpoints for photovoltaic (PV) inverters in distribution networks. The objective is to optimize the operation of the distribution feeder according to a variety of performance objectives and ensure voltage regulation. In general, these algorithms take a form of the widely studied ac optimal power flow (OPF) problem. For the envisioned application domain, nonlinear power-flow constraints render pertinent OPF problems nonconvex and computationally intensive for large systems. To address these concerns, we formulate a quadratic constrained quadratic program (QCQP) by leveraging a linear approximation of the algebraic power-flow equations. Furthermore, simplification from QCQP to a linearly constrained quadratic program is provided under certain conditions. The merits of the proposed approach are demonstrated with simulation results that utilize realistic PV-generation and load-profile data for illustrative distribution-system test feeders.

  19. Limits and Economic Effects of Distributed PV Generation in North and South Carolina

    NASA Astrophysics Data System (ADS)

    Holt, Kyra Moore

    The variability of renewable sources, such as wind and solar, when integrated into the electrical system must be compensated by traditional generation sources in-order to maintain the constant balance of supply and demand required for grid stability. The goal of this study is to analyze the effects of increasing large levels of solar Photovoltaic (PV) penetration (in terms of a percentage of annual energy production) on a test grid with similar characteristics to the Duke Energy Carolinas (DEC) and Progress Energy Carolinas (PEC) regions of North and South Carolina. PV production is modeled entering the system at the distribution level and regional PV capacity is based on household density. A gridded hourly global horizontal irradiance (GHI) dataset is used to capture the variable nature of PV generation. A unit commitment model (UCM) is then used determine the hourly dispatch of generators based on generator parameters and costs to supply generation to meet demand. Annual modeled results for six different scenarios are evaluated to determine technical, environmental and economic effects of varying levels of distributed PV penetration on the system. This study finds that the main limiting factor for PV integration in the DEC and PEC balancing authority regions is defined by the large generating capacity of base-load nuclear plants within the system. This threshold starts to affect system stability at integration levels of 5.7%. System errors, defined by imbalances caused by over or under generation with respect to demand, are identified in the model however the validity of these errors in real world context needs further examination due to the lack of high frequency irradiance data and modeling limitations. Operational system costs decreased as expected with PV integration although further research is needed to explore the impacts of the capital costs required to achieve the penetration levels found in this study. PV system generation was found to mainly displace

  20. PV Derived Data for Predicting Performance; NREL (National Renewable Energy Laboratory)

    SciTech Connect

    Marion, Bill

    2015-09-14

    A method is described for providing solar irradiance data for modeling PV performance by using measured PV performance data and back-solving for the unknown direct normal irradiance (DNI) and diffuse horizontal irradiance (DHI), which can then be used to model the performance of PV systems of any size, PV array tilt, or PV array azimuth orientation. Ideally situated for using the performance data from PV modules with micro-inverters, the PV module operating current is used to determine the global tilted irradiance (GTI), and a separation model is then used to determine the DNI and DHI from the GTI.

  1. Optimal Parameter Selection for Support Vector Machine Based on Artificial Bee Colony Algorithm: A Case Study of Grid-Connected PV System Power Prediction

    PubMed Central

    2017-01-01

    Predicting the output power of photovoltaic system with nonstationarity and randomness, an output power prediction model for grid-connected PV systems is proposed based on empirical mode decomposition (EMD) and support vector machine (SVM) optimized with an artificial bee colony (ABC) algorithm. First, according to the weather forecast data sets on the prediction date, the time series data of output power on a similar day with 15-minute intervals are built. Second, the time series data of the output power are decomposed into a series of components, including some intrinsic mode components IMFn and a trend component Res, at different scales using EMD. The corresponding SVM prediction model is established for each IMF component and trend component, and the SVM model parameters are optimized with the artificial bee colony algorithm. Finally, the prediction results of each model are reconstructed, and the predicted values of the output power of the grid-connected PV system can be obtained. The prediction model is tested with actual data, and the results show that the power prediction model based on the EMD and ABC-SVM has a faster calculation speed and higher prediction accuracy than do the single SVM prediction model and the EMD-SVM prediction model without optimization. PMID:28912803

  2. Fuzzy-PI-based centralised control of semi-isolated FP-SEPIC/ZETA BDC in a PV/battery hybrid system

    NASA Astrophysics Data System (ADS)

    Mahendran, Venmathi; Ramabadran, Ramaprabha

    2016-11-01

    Multiport converters with centralised controller have been most commonly used in stand-alone photovoltaic (PV)/battery hybrid system to supply the load smoothly without any disturbances. This study presents the performance analysis of four-port SEPIC/ZETA bidirectional converter (FP-SEPIC/ZETA BDC) using various types of centralised control schemes like Fuzzy tuned proportional integral controller (Fuzzy-PI), fuzzy logic controller (FLC) and conventional proportional integral (PI) controller. The proposed FP-SEPIC/ZETA BDC with various control strategy is derived for simultaneous power management of a PV source using distributed maximum power point tracking (DMPPT) algorithm, a rechargeable battery, and a load by means of centralised controller. The steady state and the dynamic response of the FP-SEPIC/ZETA BDC are analysed using three different types of controllers under line and load regulation. The Fuzzy-PI-based control scheme improves the dynamic response of the system when compared with the FLC and the conventional PI controller. The power balance between the ports is achieved by pseudorandom carrier modulation scheme. The response of the FP-SEPIC/ZETA BDC is also validated experimentally using hardware prototype model of 500 W system. The effectiveness of the control strategy is validated using simulation and experimental results.

  3. Breaking through market barriers with an improved sizing method: Case study of a stand-alone PV system in the northern Sudan

    SciTech Connect

    Lewis, G. )

    1990-12-01

    According to the sizing methodology used here, a stand-alone photovoltaic irrigation water-pumping system for installation in northern Sudan would cost less than anticipated by other sizing methods. This method makes use of the concept of system reliability or availability without the attendant computational complexity or unwieldiness associated with many other sizing methodologies presented in the literature. Thus, two barriers to the use of photovoltaic systems for electricity generation are addressed by an improved method of estimation. One is the commonly cited claim that PV systems are too costly. The other is that the computer-aided design methods for predicting performance are too complex or difficult to use. This makes one wonder if other objections to the use of renewable-energy technologies could be overcome through improving methods of specifying systems. 19 refs., 4 figs., 1 tab.

  4. PV performance modeling workshop summary report.

    SciTech Connect

    Stein, Joshua S.; Tasca, Coryne Adelle; Cameron, Christopher P.

    2011-05-01

    During the development of a solar photovoltaic (PV) energy project, predicting expected energy production from a system is a key part of understanding system value. System energy production is a function of the system design and location, the mounting configuration, the power conversion system, and the module technology, as well as the solar resource. Even if all other variables are held constant, annual energy yield (kWh/kWp) will vary among module technologies because of differences in response to low-light levels and temperature. A number of PV system performance models have been developed and are in use, but little has been published on validation of these models or the accuracy and uncertainty of their output. With support from the U.S. Department of Energy's Solar Energy Technologies Program, Sandia National Laboratories organized a PV Performance Modeling Workshop in Albuquerque, New Mexico, September 22-23, 2010. The workshop was intended to address the current state of PV system models, develop a path forward for establishing best practices on PV system performance modeling, and set the stage for standardization of testing and validation procedures for models and input parameters. This report summarizes discussions and presentations from the workshop, as well as examines opportunities for collaborative efforts to develop objective comparisons between models and across sites and applications.

  5. Study of Potential Cost Reductions Resulting from Super-Large-Scale Manufacturing of PV Modules: Final Subcontract Report, 7 August 2003--30 September 2004

    SciTech Connect

    Keshner, M. S.; Arya, R.

    2004-10-01

    Hewlett Packard has created a design for a ''Solar City'' factory that will process 30 million sq. meters of glass panels per year and produce 2.1-3.6 GW of solar panels per year-100x the volume of a typical, thin-film, solar panel manufacturer in 2004. We have shown that with a reasonable selection of materials, and conservative assumptions, this ''Solar City'' can produce solar panels and hit the price target of $1.00 per peak watt (6.5x-8.5x lower than prices in 2004) as the total price for a complete and installed rooftop (or ground mounted) solar energy system. This breakthrough in the price of solar energy comes without the need for any significant new invention. It comes entirely from the manufacturing scale of a large plant and the cost savings inherent in operating at such a large manufacturing scale. We expect that further optimizations from these simple designs will lead to further improvements in cost. The manufacturing process and cost depend on the choice for the active layer that converts sunlight into electricity. The efficiency by which sunlight is converted into electricity can range from 7% to 15%. This parameter has a large effect on the overall price per watt. There are other impacts, as well, and we have attempted to capture them without creating undue distractions. Our primary purpose is to demonstrate the impact of large-scale manufacturing. This impact is largely independent of the choice of active layer. It is not our purpose to compare the pro's and con's for various types of active layers. Significant improvements in cost per watt can also come from scientific advances in active layers that lead to higher efficiency. But, again, our focus is on manufacturing gains and not on the potential advances in the basic technology.

  6. Efficient Power Converters for PV Arrays : Scalable Submodule Power Conversion for Utility-Scale Photovoltaics

    SciTech Connect

    2012-02-23

    Solar ADEPT Project: SolarBridge is developing a new power conversion technique to improve the energy output of PV power plants. This new technique is specifically aimed at large plants where many solar panels are connected together. SolarBridge is correcting for the inefficiencies that occur when two solar panels that encounter different amounts of sun are connected together. In most conventional PV system, the weakest panel limits the energy production of the entire system. That’s because all of the energy collected by the PV system feeds into a single collection point where a central inverter then converts it into useable energy for the grid. SolarBridge has found a more efficient and cost-effective way to convert solar energy, correcting these power differences before they reach the grid.

  7. Solar Access to Public Capital (SAPC) Working Group: Best Practices in PV System Installation; Version 1.0, March 2015; Period of Performance, October 2014 - September 2015

    SciTech Connect

    Doyle, C.; Truitt, A.; Inda, D.; Lawrence, R.; Lockhart, R.; Golden, M.

    2015-03-01

    The following Photovoltaics Installation Best Practices Guide is one of several work products developed by the Solar Access to Public Capital (SAPC) working group, which works to open capital market investment. SAPC membership includes over 450 leading solar developers, financiers and capital managers, law firms, rating agencies, accounting and engineering firms, and other stakeholders engaged in solar asset deployment. SAPC activities are directed toward foundational elements necessary to pool project cash flows into tradable securities: standardization of power purchase and lease contracts for residential and commercial end customers; development of performance and credit data sets to facilitate investor due diligence activities; comprehension of risk perceived by rating agencies; and the development of best practice guides for PV system installation and operations and maintenance (O&M) in order to encourage high-quality system deployment and operation that may improve lifetime project performance and energy production. This PV Installation Best Practices Guide was developed through the SAPC Installation Best Practices subcommittee, a subgroup of SAPC comprised of a wide array of solar industry leaders in numerous fields of practice. The guide was developed over roughly one year and eight months of direct engagement by the subcommittee and two working group comment periods.

  8. Environmental interaction implications for large space systems

    NASA Technical Reports Server (NTRS)

    Miller, E.; Fischbein, W.; Stauber, M. C.; Suh, P. K.

    1979-01-01

    Large Space Systems (LSS) comprise a new class of spacecraft, the design and performance of which may be seriously affected by a variety of environmental interactions. The special concerns associated with spacecraft charging and plasma interactions from the LSS designer's viewpoint are addressed. Survivability of these systems under combined solar U.V., particle radiation and repeated electrical discharges is of primary importance. Additional questions regard the character of electrical discharges over very large areas, the effects of high current/voltage systems and magnitude of induced structural disturbances. A concept is described for a large scale experiment platform.

  9. Jettison system for a large inflatable antenna

    NASA Technical Reports Server (NTRS)

    Jarosz, Don; Hendricks, Steven; Landis, Dave; Tooley, Craig; Martins, Greg

    1996-01-01

    This paper describes a jettison system used to separate a large, inflatable-deployable antenna from a free-flying spacecraft. The jettison system consists of four discrete Marman band clamps, released simultaneously via pyrotechnics. The design, analysis, analytical simulation, and testing of the system are discussed. Of particular note is the correlation of test results with the Marman band design calculations.

  10. Large Scale Integration of Renewable Power Sources into the Vietnamese Power System

    NASA Astrophysics Data System (ADS)

    Kies, Alexander; Schyska, Bruno; Thanh Viet, Dinh; von Bremen, Lueder; Heinemann, Detlev; Schramm, Stefan

    2017-04-01

    The Vietnamese Power system is expected to expand considerably in upcoming decades. Power capacities installed are projected to grow from 39 GW in 2015 to 129.5 GW by 2030. Installed wind power capacities are expected to grow to 6 GW (0.8 GW 2015) and solar power capacities to 12 GW (0.85 GW 2015). This goes hand in hand with an increase of the renewable penetration in the power mix from 1.3% from wind and photovoltaics (PV) in 2015 to 5.4% by 2030. The overall potential for wind power in Vietnam is estimated to be around 24 GW. Moreover, the up-scaling of renewable energy sources was formulated as one of the priorized targets of the Vietnamese government in the National Power Development Plan VII. In this work, we investigate the transition of the Vietnamese power system towards high shares of renewables. For this purpose, we jointly optimise the expansion of renewable generation facilities for wind and PV, and the transmission grid within renewable build-up pathways until 2030 and beyond. To simulate the Vietnamese power system and its generation from renewable sources, we use highly spatially and temporally resolved historical weather and load data and the open source modelling toolbox Python for Power System Analysis (PyPSA). We show that the highest potential of renewable generation for wind and PV is observed in southern Vietnam and discuss the resulting need for transmission grid extensions in dependency of the optimal pathway. Furthermore, we show that the smoothing effect of wind power has several considerable beneficial effects and that the Vietnamese hydro power potential can be efficiently used to provide balancing opportunities. This work is part of the R&D Project "Analysis of the Large Scale Integration of Renewable Power into the Future Vietnamese Power System" (GIZ, 2016-2018).

  11. EFG Technology and Diagnostic R&D for Large-Scale PV Manufacturing; Final Subcontract Report, 1 March 2002 - 31 March 2005

    SciTech Connect

    Kalejs, J.; Aurora, P.; Bathey, B.; Cao, J.; Doedderlein, J.; Gonsiorawski, R.; Heath, B.; Kubasti, J.; Mackintosh, B.; Ouellette, M.; Rosenblum, M.; Southimath, S.; Xavier, G.

    2005-10-01

    The objective of this subcontract was to carry out R&D to advance the technology, processes, and performance of RWE Schott-Solar's wafer, cell, and module manufacturing lines, and help configure these lines for scaling up of edge-defined, film-fed growth (EFG) ribbon technology to the 50-100 MW PV factory level. EFG ribbon manufacturing continued to expand during this subcontract period and now has reached a capacity of 40 MW. EFG wafer products were diversified over this time period. In addition to 10 cm x 10 cm and 10 cm x 15 cm wafer areas, which were the standard products at the beginning of this program, R&D has focused on new EFG technology to extend production to 12.5 cm x 12.5 cm EFG wafers. Cell and module production also has continued to expand in Billerica. A new 12-MW cell line was installed and brought on line in 2003. R&D on this subcontract improved cell yield and throughput, and optimized the cell performance, with special emphasis on work to speed up wafer transfer, hence enhancing throughput. Improvements of wafer transfer processes during this program have raised cell line capacity from 12 MW to over 18 MW. Optimization of module manufacturing processes was carried out on new equipment installed during a manufacturing upgrade in Billerica to a 12-MW capacity to improve yield and reliability of products.

  12. PV technology and success of solar electricity in Vietnam

    SciTech Connect

    Dung, T.Q.

    1997-12-31

    Since 1990 the PV Technology and the Solar electricity have been strongly developed in Vietnam. The PV experts of Solarlab have studied and set up an appropriate PV Technology responding to local Market needs. It has not only stood well but has been also transferred to Mali Republic and Lao P.D.R. The PV off grid systems of Solarlab demonstrate good efficiency and low prices. Over 60 solar stations and villages have been built to provide solar lighting for about 3000 families along the country in remote, mountainous areas and islands. 400 families are using stand-alone Solar Home Systems. The Solar electricity has been chosen for Rural Electrification and National Telecommunication Network in remote and mountainous regions. Many International projects in cooperation with FONDEM-France, SELF USA and Governmental PV projects have been realized by Solarlab. The experiences of maintenance, management and finance about PV development in Vietnam are also mentioned.

  13. Open PV Project: Unlocking PV Installation Data (Brochure)

    SciTech Connect

    Not Available

    2012-04-01

    This brochure summarizes the Open PV Project, a collaborative effort of government, industry, and the public to compile a comprehensive database of PV installations in the United States. The brochure outlines the purpose and history of the project as well as the main capabilities and benefits of the online Open PV tool. The brochure also introduces how features of the tool are used, and it describes the sources and characteristics of Open PV's data and data collection processes.

  14. Very Large System Dynamics Models - Lessons Learned

    SciTech Connect

    Jacob J. Jacobson; Leonard Malczynski

    2008-10-01

    This paper provides lessons learned from developing several large system dynamics (SD) models. System dynamics modeling practice emphasize the need to keep models small so that they are manageable and understandable. This practice is generally reasonable and prudent; however, there are times that large SD models are necessary. This paper outlines two large SD projects that were done at two Department of Energy National Laboratories, the Idaho National Laboratory and Sandia National Laboratories. This paper summarizes the models and then discusses some of the valuable lessons learned during these two modeling efforts.

  15. Utility-scale grid-tied PV inverter reliability workshop summary report.

    SciTech Connect

    Granata, Jennifer E.; Quintana, Michael A.; Tasca, Coryne Adelle; Atcitty, Stanley

    2011-07-01

    A key to the long-term success of the photovoltaic (PV) industry is confidence in the reliability of PV systems. Inverters are the most commonly noted cause of PV system incidents triggered in the field. While not all of these incidents are reliability-related or even necessarily failures, they still result in a loss of generated power. With support from the U.S. Department of Energy's Solar Energy Technologies Program, Sandia National Laboratories organized a Utility-Scale Grid-Tied Inverter Reliability Workshop in Albuquerque, New Mexico, January 27-28, 2011. The workshop addressed the reliability of large (100-kilowatt+) grid-tied inverters and the implications when such inverters fail, evaluated inverter codes and standards, and provided discussion about opportunities to enhance inverter reliability. This report summarizes discussions and presentations from the workshop and identifies opportunities for future efforts.

  16. Cell Wall Degrading Enzyme Induced Rice Innate Immune Responses Are Suppressed by the Type 3 Secretion System Effectors XopN, XopQ, XopX and XopZ of Xanthomonas oryzae pv. oryzae

    PubMed Central

    Sinha, Dipanwita; Gupta, Mahesh Kumar; Patel, Hitendra Kumar; Ranjan, Ashish; Sonti, Ramesh V.

    2013-01-01

    Innate immune responses are induced in plants and animals through perception of Damage Associated Molecular Patterns. These immune responses are suppressed by pathogens during infection. A number of studies have focussed on identifying functions of plant pathogenic bacteria that are involved in suppression of Pathogen Associated Molecular Pattern induced immune responses. In comparison, there is very little information on functions used by plant pathogens to suppress Damage Associated Molecular Pattern induced immune responses. Xanthomonasoryzae pv. oryzae, a gram negative bacterial pathogen of rice, secretes hydrolytic enzymes such as LipA (Lipase/Esterase) that damage rice cell walls and induce innate immune responses. Here, we show that Agrobacterium mediated transient transfer of the gene for XopN, a X. oryzae pv. oryzae type 3 secretion (T3S) system effector, results in suppression of rice innate immune responses induced by LipA. A xopN- mutant of X. oryzae pv. oryzae retains the ability to suppress these innate immune responses indicating the presence of other functionally redundant proteins. In transient transfer assays, we have assessed the ability of 15 other X. oryzae pv. oryzae T3S secreted effectors to suppress rice innate immune responses. Amongst these proteins, XopQ, XopX and XopZ are suppressors of LipA induced innate immune responses. A mutation in any one of the xopN, xopQ, xopX or xopZ genes causes partial virulence deficiency while a xopN- xopX- double mutant exhibits a greater virulence deficiency. A xopN- xopQ- xopX- xopZ- quadruple mutant of X. oryzae pv. oryzae induces callose deposition, an innate immune response, similar to a X. oryzae pv. oryzae T3S- mutant in rice leaves. Overall, these results indicate that multiple T3S secreted proteins of X. oryzae pv. oryzae can suppress cell wall damage induced rice innate immune responses. PMID:24086651

  17. Cell wall degrading enzyme induced rice innate immune responses are suppressed by the type 3 secretion system effectors XopN, XopQ, XopX and XopZ of Xanthomonas oryzae pv. oryzae.

    PubMed

    Sinha, Dipanwita; Gupta, Mahesh Kumar; Patel, Hitendra Kumar; Ranjan, Ashish; Sonti, Ramesh V

    2013-01-01

    Innate immune responses are induced in plants and animals through perception of Damage Associated Molecular Patterns. These immune responses are suppressed by pathogens during infection. A number of studies have focussed on identifying functions of plant pathogenic bacteria that are involved in suppression of Pathogen Associated Molecular Pattern induced immune responses. In comparison, there is very little information on functions used by plant pathogens to suppress Damage Associated Molecular Pattern induced immune responses. Xanthomonasoryzae pv. oryzae, a gram negative bacterial pathogen of rice, secretes hydrolytic enzymes such as LipA (Lipase/Esterase) that damage rice cell walls and induce innate immune responses. Here, we show that Agrobacterium mediated transient transfer of the gene for XopN, a X. oryzae pv. oryzae type 3 secretion (T3S) system effector, results in suppression of rice innate immune responses induced by LipA. A xopN (-) mutant of X. oryzae pv. oryzae retains the ability to suppress these innate immune responses indicating the presence of other functionally redundant proteins. In transient transfer assays, we have assessed the ability of 15 other X. oryzae pv. oryzae T3S secreted effectors to suppress rice innate immune responses. Amongst these proteins, XopQ, XopX and XopZ are suppressors of LipA induced innate immune responses. A mutation in any one of the xopN, xopQ, xopX or xopZ genes causes partial virulence deficiency while a xopN (-) xopX (-) double mutant exhibits a greater virulence deficiency. A xopN (-) xopQ (-) xopX (-) xopZ (-) quadruple mutant of X. oryzae pv. oryzae induces callose deposition, an innate immune response, similar to a X. oryzae pv. oryzae T3S(-) mutant in rice leaves. Overall, these results indicate that multiple T3S secreted proteins of X. oryzae pv. oryzae can suppress cell wall damage induced rice innate immune responses.

  18. Transient electromagnetic fields near large earthing systems

    SciTech Connect

    Grcev, L.D.; Menter, F.E.

    1996-05-01

    Electromagnetic compatibility studies require knowledge of transient voltages that may be developed near earthing systems during lightning discharge, since such voltages may be coupled to sensitive electronic circuits. For such purpose accurate evaluation of transient electric field near to and/or at the surface of the grounding conductors is necessary. In this paper, a procedure for computation of transient fields near large earthing systems, as a response to a typical lightning current impulse, based on computational methodology developed in the field of antennas, is presented. Computed results are favorably compared with published measurement results. The model is applied to check the common assumption that the soil ionization can be neglected in case of large earthing systems. Presented results show that the soil ionization threshold is met and exceeded during typical lightning discharge in a large earthing system.

  19. Advances in Structures for Large Space Systems

    NASA Technical Reports Server (NTRS)

    Belvin, W. Keith

    2004-01-01

    The development of structural systems for scientific remote sensing and space exploration has been underway for four decades. The seminal work from 1960 to 1980 provided the basis for many of the design principles of modern space systems. From 1980- 2000 advances in active materials and structures and the maturing of composites technology led to high precision active systems such those used in the Space Interferometry Mission. Recently, thin-film membrane or gossamer structures are being investigated for use in large area space systems because of their low mass and high packaging efficiency. Various classes of Large Space Systems (LSS) are defined in order to describe the goals and system challenges in structures and materials technologies. With an appreciation of both past and current technology developments, future technology challenges are used to develop a list of technology investments that can have significant impacts on LSS development.

  20. Quasi-static time-series simulation using OpenDSS in IEEE distribution feeder model with high PV penetration and its impact on solar forecasting

    NASA Astrophysics Data System (ADS)

    Mohammed, Touseef Ahmed Faisal

    Distribution System Simulator developed by Electric Power Research Institute, to simulate grid voltage profile with a large scale PV system under quasi-static time series considering variations of PV output in seconds, minutes, and the average daily load variations. A 13 bus IEEE distribution feeder model is utilized with distributed residential and commercial scale PV at different buses for simulation studies. Time series simulations are discussed for various modes of operation considering dynamic PV penetration at different time periods in a day. In addition, this thesis demonstrates simulations taking into account the presence of moving cloud for solar forecasting studies.

  1. Large autonomous spacecraft electrical power system (LASEPS)

    NASA Technical Reports Server (NTRS)

    Dugal-Whitehead, Norma R.; Johnson, Yvette B.

    1992-01-01

    NASA - Marshall Space Flight Center is creating a large high voltage electrical power system testbed called LASEPS. This testbed is being developed to simulate an end-to-end power system from power generation and source to loads. When the system is completed it will have several power configurations, which will include several battery configurations. These configurations are: two 120 V batteries, one or two 150 V batteries, and one 250 to 270 V battery. This breadboard encompasses varying levels of autonomy from remote power converters to conventional software control to expert system control of the power system elements. In this paper, the construction and provisions of this breadboard are discussed.

  2. Large autonomous spacecraft electrical power system (LASEPS)

    NASA Technical Reports Server (NTRS)

    Dugal-Whitehead, Norma R.; Johnson, Yvette B.

    1992-01-01

    NASA - Marshall Space Flight Center is creating a large high voltage electrical power system testbed called LASEPS. This testbed is being developed to simulate an end-to-end power system from power generation and source to loads. When the system is completed it will have several power configurations, which will include several battery configurations. These configurations are: two 120 V batteries, one or two 150 V batteries, and one 250 to 270 V battery. This breadboard encompasses varying levels of autonomy from remote power converters to conventional software control to expert system control of the power system elements. In this paper, the construction and provisions of this breadboard are discussed.

  3. Testing for PV Reliability (Presentation)

    SciTech Connect

    Kurtz, S.; Bansal, S.

    2014-09-01

    The DOE SUNSHOT workshop is seeking input from the community about PV reliability and how the DOE might address gaps in understanding. This presentation describes the types of testing that are needed for PV reliability and introduces a discussion to identify gaps in our understanding of PV reliability testing.

  4. Probabilistic voltage security for large scale power systems

    NASA Astrophysics Data System (ADS)

    Poshtan, Majid

    2000-10-01

    Stability is one of the most important problems in power system operation and control. Voltage instability is one type of power system instability that occurs when the system operates close to its limits. Progressive voltage instability, which is also referred to as Voltage Collapse, results in loss of voltage at certain nodes (buses) in the system. Voltage collapse, a slowly occurring phenomena leading to loss of voltage at specific parts of an electric utility, has been observed in the USA, Europe, Japan, Canada, and other places in the world during the past decade. Voltage collapse typically occurs on power systems which are heavily loaded, faulted and/or have reactive power shortages. There are several power system's parameter changes known to contribute to voltage collapse. The most important contributors to voltage instability are: increasing load, generators or SVC reaching reactive power limits, action of tap-changing transformers, line tripping, and generator outages. The differences between voltage collapse and lack of classical transient stability is that in voltage collapse we focus on loads and voltage magnitudes whereas in classical transient stability the focus is on generators' dynamics and voltage angles. Also voltage collapse often includes longer time scale dynamics and includes the effects of continuous changes such as load increases in addition to discrete events such as line outages. Two conventional methods to analyze voltage collapse are P-V and V-Q curves, and modal analyses. Both methods are deterministic and do not encounter any probability for the contingencies causing the voltage collapse. The purpose of this investigation is to identify probabilistic indices to assess the steady-state voltage stability by considering random failures and their dependency in a large-scale power system. The research mainly continues the previous research completed at Tulane University by Dr. J. Bian and Professor P. Rastgoufard and will complement it by

  5. Advanced Grid-Friendly Controls Demonstration Project for Utility-Scale PV Power Plants

    SciTech Connect

    Gevorgian, Vahan; O'Neill, Barbara

    2016-01-21

    A typical photovoltaic (PV) power plant consists of multiple power electronic inverters and can contribute to grid stability and reliability through sophisticated 'grid-friendly' controls. The availability and dissemination of actual test data showing the viability of advanced utility-scale PV controls among all industry stakeholders can leverage PV's value from being simply an energy resource to providing additional ancillary services that range from variability smoothing and frequency regulation to power quality. Strategically partnering with a selected utility and/or PV power plant operator is a key condition for a successful demonstration project. The U.S. Department of Energy's (DOE's) Solar Energy Technologies Office selected the National Renewable Energy Laboratory (NREL) to be a principal investigator in a two-year project with goals to (1) identify a potential partner(s), (2) develop a detailed scope of work and test plan for a field project to demonstrate the gird-friendly capabilities of utility-scale PV power plants, (3) facilitate conducting actual demonstration tests, and (4) disseminate test results among industry stakeholders via a joint NREL/DOE publication and participation in relevant technical conferences. The project implementation took place in FY 2014 and FY 2015. In FY14, NREL established collaborations with AES and First Solar Electric, LLC, to conduct demonstration testing on their utility-scale PV power plants in Puerto Rico and Texas, respectively, and developed test plans for each partner. Both Puerto Rico Electric Power Authority and the Electric Reliability Council of Texas expressed interest in this project because of the importance of such advanced controls for the reliable operation of their power systems under high penetration levels of variable renewable generation. During FY15, testing was completed on both plants, and a large amount of test data was produced and analyzed that demonstrates the ability of PV power plants to

  6. Formal Verification of Large Software Systems

    NASA Technical Reports Server (NTRS)

    Yin, Xiang; Knight, John

    2010-01-01

    We introduce a scalable proof structure to facilitate formal verification of large software systems. In our approach, we mechanically synthesize an abstract specification from the software implementation, match its static operational structure to that of the original specification, and organize the proof as the conjunction of a series of lemmas about the specification structure. By setting up a different lemma for each distinct element and proving each lemma independently, we obtain the important benefit that the proof scales easily for large systems. We present details of the approach and an illustration of its application on a challenge problem from the security domain

  7. [Large vessels vasculopathy in systemic sclerosis].

    PubMed

    Tejera Segura, Beatriz; Ferraz-Amaro, Iván

    2015-12-07

    Vasculopathy in systemic sclerosis is a severe, in many cases irreversible, manifestation that can lead to amputation. While the classical clinical manifestations of the disease have to do with the involvement of microcirculation, proximal vessels of upper and lower limbs can also be affected. This involvement of large vessels may be related to systemic sclerosis, vasculitis or atherosclerotic, and the differential diagnosis is not easy. To conduct a proper and early diagnosis, it is essential to start prompt appropriate treatment. In this review, we examine the involvement of large vessels in scleroderma, an understudied manifestation with important prognostic and therapeutic implications.

  8. Very Large-Scale Deployment of Grid-Connected Solar Photovoltaics in the United States: Challenges and Opportunities; Preprint

    SciTech Connect

    Denholm, P.; Margolis, R.

    2006-04-01

    This paper analyzes the potential for solar photovoltaics (PV) to be deployed on a very large scale and provide a large fraction of a system's electricity. It explicitly examines how the hourly availability of PV interacts with the limited flexibility of traditional electricity generation plants. The authors found that, under high penetration levels and existing grid-operation procedures and rules, the system will have excess PV generation during certain periods of the year. This excess PV generation results in increased costs, which can increase dramatically when PV provides on the order of 10%-15% of total electricity demand in systems that are heavily dependent on inflexible baseload steam plants. Measures to increase penetration of PV are also discussed, including increased system flexibility, increased dispatchable load, and energy storage.

  9. Data acquisition system issues for large experiments

    NASA Astrophysics Data System (ADS)

    Siskind, E. J.

    2007-09-01

    This talk consists of personal observations on two classes of data acquisition ("DAQ") systems for Silicon trackers in large experiments with which the author has been concerned over the last three or more years. The first half is a classic "lessons learned" recital based on experience with the high-level debug and configuration of the DAQ system for the GLAST LAT detector. The second half is concerned with a discussion of the promises and pitfalls of using modern (and future) generations of "system-on-a-chip" ("SOC") or "platform" field-programmable gate arrays ("FPGAs") in future large DAQ systems. The DAQ system pipeline for the 864k channels of Si tracker in the GLAST LAT consists of five tiers of hardware buffers which ultimately feed into the main memory of the (two-active-node) level-3 trigger processor farm. The data formats and buffer volumes of these tiers are briefly described, as well as the flow control employed between successive tiers. Lessons learned regarding data formats, buffer volumes, and flow control/data discard policy are discussed. The continued development of platform FPGAs containing large amounts of configurable logic fabric, embedded PowerPC hard processor cores, digital signal processing components, large volumes of on-chip buffer memory, and multi-gigabit serial I/O capability permits DAQ system designers to vastly increase the amount of data preprocessing that can be performed in parallel within the DAQ pipeline for detector systems in large experiments. The capabilities of some currently available FPGA families are reviewed, along with the prospects for next-generation families of announced, but not yet available, platform FPGAs. Some experience with an actual implementation is presented, and reconciliation between advertised and achievable specifications is attempted. The prospects for applying these components to space-borne Si tracker detectors are briefly discussed.

  10. Comparative Analysis and Considerations for PV Interconnection Standards in the United States and China

    SciTech Connect

    Gao, David Wenzhong; Muljadi, Eduard; Tian, Tian; Miller, Mackay

    2017-01-01

    The main objectives of this report are to evaluate China's photovoltaic (PV) interconnection standards and the U.S. counterparts and to propose recommendations for future revisions to these standards. This report references the 2013 report Comparative Study of Standards for Grid-Connected PV System in China, the U.S. and European Countries, which compares U.S., European, and China's PV grid interconnection standards; reviews various metrics for the characterization of distribution network with PV; and suggests modifications to China's PV interconnection standards and requirements. The recommendations are accompanied by assessments of four high-penetration PV grid interconnection cases in the United States to illustrate solutions implemented to resolve issues encountered at different sites. PV penetration in China and in the United States has significantly increased during the past several years, presenting comparable challenges depending on the conditions of the grid at the point of interconnection; solutions are generally unique to each interconnected PV installation or PV plant.

  11. Quality Function Deployment for Large Systems

    NASA Technical Reports Server (NTRS)

    Dean, Edwin B.

    1992-01-01

    Quality Function Deployment (QFD) is typically applied to small subsystems. This paper describes efforts to extend QFD to large scale systems. It links QFD to the system engineering process, the concurrent engineering process, the robust design process, and the costing process. The effect is to generate a tightly linked project management process of high dimensionality which flushes out issues early to provide a high quality, low cost, and, hence, competitive product. A pre-QFD matrix linking customers to customer desires is described.

  12. Camera Systems Rapidly Scan Large Structures

    NASA Technical Reports Server (NTRS)

    2013-01-01

    Needing a method to quickly scan large structures like an aircraft wing, Langley Research Center developed the line scanning thermography (LST) system. LST works in tandem with a moving infrared camera to capture how a material responds to changes in temperature. Princeton Junction, New Jersey-based MISTRAS Group Inc. now licenses the technology and uses it in power stations and industrial plants.

  13. Method to Utilize Surplus Electric Power of Photovoltaic Systems by Heat Pump Water Heaters

    NASA Astrophysics Data System (ADS)

    Hatta, Hiroyuki; Kobayashi, Hiromu

    Large capacity photovoltaic (PV) systems will be installed in future power systems. According to Japan's energy outlook, the target capacity of PV systems for 2030 is about 50GW. When the large volume PV systems are installed in a power system, the reverse power flow from PV systems may cause the surplus electric power. To utilize the surplus electric power without the reduction of PV power generation, operation of customer equipment such as heat pump water heater (HPWH) according to PV power generation is expected to be one of the solutions. In this paper, cooperative control method of customer equipment with the PV power generation is proposed, and the effectiveness of the proposed control is evaluated by simulation analyses.

  14. Stability analysis of large electric power systems

    SciTech Connect

    Elwood, D.M.

    1993-01-01

    Modern electric power systems are large and complicated, and, in many regions of the world, the generation and transmission systems are operating near their limits. Ensuring the reliable operation of the power system requires engineers to study the response of the system to various disturbances. The responses to large disturbances are examined by numerically solving the nonlinear differential-algebraic equations describing the power system. The response to small disturbances is typically studied via eigenanalysis. The Electric Power Research Institute (EPRI) recently developed the Extended Transient/Mid-term Stability Program (ETMSP) to study large disturbance stability and the Small Signal Stability Program Package (SSSP) to study small signal stability. The primary objectives of the work described in this report were to (1) explore ways of speeding up ETMSP, especially on mid-term voltage stability problems, (2) explore ways of speeding up the Multi-Area Small-Signal Stability program (MASS), one of the codes in SSSP, and (3) explore ways of increasing the size of problem that can be solved by the Cray version of MASS.

  15. Three-phase power conversion system for utility-interconnected PV applications. Phase 1 technical progress report, 1 October 1995--17 April 1997

    SciTech Connect

    Porter, D.G.; Meyer, H.; Leang, W.

    1998-02-01

    This report describes work performed by Omnion Power Corporation under Phase 1 of a two-phase subcontract. During this phase, Omnion researchers: designed an advanced product specification to guide prototype design and development; analyzed field failure data with Omnion`s hard-switched insulated-Gate Bipolar Transistor technology hardware to better understand where design improvements were needed; presented and reviewed product specifications with key customers/users; drafted a working product specification to serve as a baseline in developing the new power conversion system; developed the core-resonant converter technology in conjunction with Soft Switching Technologies Corp.; designed a 100-kW prototype power conversion system; designed a prototype system package; initiated interaction with vendors to optimize component selection and specifications; initiated the preparation of design documentation; built the prototype core-resonant converter and initiated preliminary testing; and initiated the assembly of a 1-kW prototype power conversion system. This work has demonstrated the potential of the soft-switching resonant DC link (RDCL) inverter and its application to a three-phase utility-interconnected PV power conversion system. The RDCL inverter has demonstrated its advantage over hard-switching pulse-width modulated inverters in terms of efficiency and audible noise. With proper package design and manufacturing process design and implementation, the RDCL power conversion system has the potential to be low-cost and reliable with superior performance.

  16. Design of Large Momentum Acceptance Transport Systems

    SciTech Connect

    D.R. Douglas

    2005-05-01

    The use of energy recovery to enable high power linac operation often gives rise to an attendant challenge--the transport of high power beams subtending large phase space volumes. In particular applications--such as FEL driver accelerators--this manifests itself as a requirement for beam transport systems with large momentum acceptance. We will discuss the design, implementation, and operation of such systems. Though at times counterintuitive in behavior (perturbative descriptions may, for example, be misleading), large acceptance systems have been successfully utilized for generations as spectrometers and accelerator recirculators [1]. Such systems are in fact often readily designed using appropriate geometric descriptions of beam behavior; insight provided using such a perspective may in addition reveal inherent symmetries that simplify construction and improve operability. Our discussion will focus on two examples: the Bates-clone recirculator used in the Jefferson Lab 10 kW IR U pgrade FEL (which has an observed acceptance of 10% or more) and a compaction-managed mirror-bend achromat concept with an acceptance ranging from 50 to 150 MeV.

  17. Large-Scale Structures of Planetary Systems

    NASA Astrophysics Data System (ADS)

    Murray-Clay, Ruth; Rogers, Leslie A.

    2015-12-01

    A class of solar system analogs has yet to be identified among the large crop of planetary systems now observed. However, since most observed worlds are more easily detectable than direct analogs of the Sun's planets, the frequency of systems with structures similar to our own remains unknown. Identifying the range of possible planetary system architectures is complicated by the large number of physical processes that affect the formation and dynamical evolution of planets. I will present two ways of organizing planetary system structures. First, I will suggest that relatively few physical parameters are likely to differentiate the qualitative architectures of different systems. Solid mass in a protoplanetary disk is perhaps the most obvious possible controlling parameter, and I will give predictions for correlations between planetary system properties that we would expect to be present if this is the case. In particular, I will suggest that the solar system's structure is representative of low-metallicity systems that nevertheless host giant planets. Second, the disk structures produced as young stars are fed by their host clouds may play a crucial role. Using the observed distribution of RV giant planets as a function of stellar mass, I will demonstrate that invoking ice lines to determine where gas giants can form requires fine tuning. I will suggest that instead, disk structures built during early accretion have lasting impacts on giant planet distributions, and disk clean-up differentially affects the orbital distributions of giant and lower-mass planets. These two organizational hypotheses have different implications for the solar system's context, and I will suggest observational tests that may allow them to be validated or falsified.

  18. Mitigating Interconnection Challenges of the High Penetration Utility-Interconnected Photovoltaic (PV) in the Electrical Distribution Systems: Cooperative Research and Development Final Report, CRADA Number CRD-14-563

    SciTech Connect

    Chakraborty, Sudipta

    2016-11-01

    Various interconnection challenges exist when connecting distributed PV into the electrical distribution grid in terms of safety, reliability, and stability of the electric power systems. Some of the urgent areas for research, as identified by inverter manufacturers, installers and utilities, are potential for transient overvoltage from PV inverters, multi-inverter anti-islanding, impact of smart inverters on volt-VAR support, impact of bidirectional power flow, and potential for distributed generation curtailment solutions to mitigate grid stability challenges. Under this project, NREL worked with SolarCity to address these challenges through research, testing and analysis at the Energy System Integration Facility (ESIF). Inverters from different manufacturers were tested at ESIF and NREL's unique power hardware-in-the-loop (PHIL) capability was utilized to evaluate various system-level impacts. Through the modeling, simulation, and testing, this project eliminated critical barriers on high PV penetration and directly supported the Department of Energy's SunShot goal of increasing the solar PV on the electrical grid.

  19. Large-scale Intelligent Transporation Systems simulation

    SciTech Connect

    Ewing, T.; Canfield, T.; Hannebutte, U.; Levine, D.; Tentner, A.

    1995-06-01

    A prototype computer system has been developed which defines a high-level architecture for a large-scale, comprehensive, scalable simulation of an Intelligent Transportation System (ITS) capable of running on massively parallel computers and distributed (networked) computer systems. The prototype includes the modelling of instrumented ``smart`` vehicles with in-vehicle navigation units capable of optimal route planning and Traffic Management Centers (TMC). The TMC has probe vehicle tracking capabilities (display position and attributes of instrumented vehicles), and can provide 2-way interaction with traffic to provide advisories and link times. Both the in-vehicle navigation module and the TMC feature detailed graphical user interfaces to support human-factors studies. The prototype has been developed on a distributed system of networked UNIX computers but is designed to run on ANL`s IBM SP-X parallel computer system for large scale problems. A novel feature of our design is that vehicles will be represented by autonomus computer processes, each with a behavior model which performs independent route selection and reacts to external traffic events much like real vehicles. With this approach, one will be able to take advantage of emerging massively parallel processor (MPP) systems.

  20. The Predicted Lytic Transglycosylase HpaH from Xanthomonas campestris pv. vesicatoria Associates with the Type III Secretion System and Promotes Effector Protein Translocation

    PubMed Central

    Hausner, Jens; Hartmann, Nadine; Jordan, Michael

    2016-01-01

    ABSTRACT The pathogenicity of the Gram-negative plant-pathogenic bacterium Xanthomonas campestris pv. vesicatoria depends on a type III secretion (T3S) system, which spans both bacterial membranes and translocates effector proteins into plant cells. The assembly of the T3S system presumably involves the predicted lytic transglycosylase (LT) HpaH, which is encoded adjacent to the T3S gene cluster. Bacterial LTs degrade peptidoglycan and often promote the formation of membrane-spanning macromolecular protein complexes. In the present study, we show that HpaH localizes to the bacterial periplasm and binds to peptidoglycan as well as to components of the T3S system, including the predicted periplasmic inner rod proteins HrpB1 and HrpB2 as well as the pilus protein HrpE. In vivo translocation assays revealed that HpaH promotes the translocation of various effector proteins and of early substrates of the T3S system, suggesting a general contribution of HpaH to type III-dependent protein export. Mutant studies and the analysis of reporter fusions showed that the N-terminal region of HpaH contributes to protein function and is proteolytically cleaved. The N-terminally truncated HpaH cleavage product is secreted into the extracellular milieu by a yet-unknown transport pathway, which is independent of the T3S system. PMID:27895129

  1. The Predicted Lytic Transglycosylase HpaH from Xanthomonas campestris pv. vesicatoria Associates with the Type III Secretion System and Promotes Effector Protein Translocation.

    PubMed

    Hausner, Jens; Hartmann, Nadine; Jordan, Michael; Büttner, Daniela

    2017-02-01

    The pathogenicity of the Gram-negative plant-pathogenic bacterium Xanthomonas campestris pv. vesicatoria depends on a type III secretion (T3S) system, which spans both bacterial membranes and translocates effector proteins into plant cells. The assembly of the T3S system presumably involves the predicted lytic transglycosylase (LT) HpaH, which is encoded adjacent to the T3S gene cluster. Bacterial LTs degrade peptidoglycan and often promote the formation of membrane-spanning macromolecular protein complexes. In the present study, we show that HpaH localizes to the bacterial periplasm and binds to peptidoglycan as well as to components of the T3S system, including the predicted periplasmic inner rod proteins HrpB1 and HrpB2 as well as the pilus protein HrpE. In vivo translocation assays revealed that HpaH promotes the translocation of various effector proteins and of early substrates of the T3S system, suggesting a general contribution of HpaH to type III-dependent protein export. Mutant studies and the analysis of reporter fusions showed that the N-terminal region of HpaH contributes to protein function and is proteolytically cleaved. The N-terminally truncated HpaH cleavage product is secreted into the extracellular milieu by a yet-unknown transport pathway, which is independent of the T3S system. Copyright © 2017 American Society for Microbiology.

  2. Indirect adaptive soft computing based wavelet-embedded control paradigms for WT/PV/SOFC in a grid/charging station connected hybrid power system

    PubMed Central

    Khan, Laiq; Ahmed, Saghir; Bader, Rabiah

    2017-01-01

    This paper focuses on the indirect adaptive tracking control of renewable energy sources in a grid-connected hybrid power system. The renewable energy systems have low efficiency and intermittent nature due to unpredictable meteorological conditions. The domestic load and the conventional charging stations behave in an uncertain manner. To operate the renewable energy sources efficiently for harvesting maximum power, instantaneous nonlinear dynamics should be captured online. A Chebyshev-wavelet embedded NeuroFuzzy indirect adaptive MPPT (maximum power point tracking) control paradigm is proposed for variable speed wind turbine-permanent synchronous generator (VSWT-PMSG). A Hermite-wavelet incorporated NeuroFuzzy indirect adaptive MPPT control strategy for photovoltaic (PV) system to extract maximum power and indirect adaptive tracking control scheme for Solid Oxide Fuel Cell (SOFC) is developed. A comprehensive simulation test-bed for a grid-connected hybrid power system is developed in Matlab/Simulink. The robustness of the suggested indirect adaptive control paradigms are evaluated through simulation results in a grid-connected hybrid power system test-bed by comparison with conventional and intelligent control techniques. The simulation results validate the effectiveness of the proposed control paradigms. PMID:28877191

  3. Indirect adaptive soft computing based wavelet-embedded control paradigms for WT/PV/SOFC in a grid/charging station connected hybrid power system.

    PubMed

    Mumtaz, Sidra; Khan, Laiq; Ahmed, Saghir; Bader, Rabiah

    2017-01-01

    This paper focuses on the indirect adaptive tracking control of renewable energy sources in a grid-connected hybrid power system. The renewable energy systems have low efficiency and intermittent nature due to unpredictable meteorological conditions. The domestic load and the conventional charging stations behave in an uncertain manner. To operate the renewable energy sources efficiently for harvesting maximum power, instantaneous nonlinear dynamics should be captured online. A Chebyshev-wavelet embedded NeuroFuzzy indirect adaptive MPPT (maximum power point tracking) control paradigm is proposed for variable speed wind turbine-permanent synchronous generator (VSWT-PMSG). A Hermite-wavelet incorporated NeuroFuzzy indirect adaptive MPPT control strategy for photovoltaic (PV) system to extract maximum power and indirect adaptive tracking control scheme for Solid Oxide Fuel Cell (SOFC) is developed. A comprehensive simulation test-bed for a grid-connected hybrid power system is developed in Matlab/Simulink. The robustness of the suggested indirect adaptive control paradigms are evaluated through simulation results in a grid-connected hybrid power system test-bed by comparison with conventional and intelligent control techniques. The simulation results validate the effectiveness of the proposed control paradigms.

  4. AtPV42a and AtPV42b Redundantly Regulate Reproductive Development in Arabidopsis thaliana

    PubMed Central

    Fang, Lei; Hou, Xingliang; Lee, Li Yen Candy; Liu, Lu; Yan, Xiaojing; Yu, Hao

    2011-01-01

    Background The conserved SNF1/AMPK/SnRK1 complexes are global regulators of metabolic responses in eukaryotes and play a key role in the control of energy balance. Although α-type subunits of the SnRK1 complex have been characterized in several plant species, the biological function of β-type and γ-type subunits remains largely unknown. Here, we characterized AtPV42a and AtPV42b, the two homologous genes in Arabidopsis, which encode cystathionine-β-synthase (CBS) domain-containing proteins that belong to the PV42 class of γ-type subunits of the plant SnRK1 complexes. Methodology/Principal Findings Real-time polymerase chain reaction was performed to examine the expression of AtPV42a and AtPV42b in various tissues. Transgenic plants that expressed artificial microRNAs targeting these two genes were created. Reproductive organ development and fertilization in these plants were examined by various approaches, including histological analysis, scanning electron microscopy, transmission electron microscopy, and phenotypic analyses of reciprocal crosses between wild-type and transgenic plants. We found that AtPV42a and AtPV42b were expressed in various tissues during different developmental stages. Transgenic plants where AtPV42a and AtPV42b were simultaneously silenced developed shorter siliques and reduced seed sets. Such low fertility phenotype resulted from deregulation of late stamen development and impairment of pollen tube attraction conferred by the female gametophyte. Conclusions Our results demonstrate that AtPV42a and AtPV42b play redundant roles in regulating male gametogenesis and pollen tube guidance, indicating that the Arabidopsis SnRK1 complexes might be involved in the control of reproductive development. PMID:21533063

  5. Ground state energy of large polaron systems

    SciTech Connect

    Benguria, Rafael D.; Frank, Rupert L.; Lieb, Elliott H.

    2015-02-15

    The last unsolved problem about the many-polaron system, in the Pekar–Tomasevich approximation, is the case of bosons with the electron-electron Coulomb repulsion of strength exactly 1 (the “neutral case”). We prove that the ground state energy, for large N, goes exactly as −N{sup 7/5}, and we give upper and lower bounds on the asymptotic coefficient that agree to within a factor of 2{sup 2/5}.

  6. Resistojet propulsion for large spacecraft systems

    NASA Technical Reports Server (NTRS)

    Mirtich, M. J.

    1982-01-01

    Resistojet propulsion systems have characteristics that are ideally suited for the on-orbit and primary propulsion requirements of large spacecraft systems. These characteristics which offer advantages over other forms of propulsion are reviewed and presented. The feasibility of resistojets were demonstrated in space whereas only a limited number of ground life tests were performed. The major technology issues associated with these ground tests are evaluated. The past performance of resistojets is summarized and, looks into the present day technology status is reviewed. The material criteria, along with possible concepts, needed to attain high performance resistojets are presented.

  7. Large spaceborne antenna technology: A system perspective

    NASA Astrophysics Data System (ADS)

    Naderi, F.

    1983-05-01

    Land Mobile Satellite System (LMSS) is a communication system which provides radio communication to a large group of users within a vast geographical area (e.g. communications to and from mobile vehicles anywhere within the U.S.). Such radio communication may be in the form of radio telephone, paging, dispatch, or data transmission. The intended applications of LMSS range from emergency medical to disaster relief, from law enforcement to truck dispatch. By providing service to vast rural areas, LMSS compliments the current terrestrial service in the metropolitan areas and hence provides for a nationally ubiquitous coverage.

  8. Feasible eigenvalue sensitivity for large power systems

    SciTech Connect

    Smed, T. . Dept. of Electric Power Systems)

    1993-05-01

    Traditional eigenvalue sensitivity for power systems requires the formulation of the system matrix, which lacks sparsity. In this paper, a new sensitivity analysis, derived for a sparse formulation, is presented. Variables that are computed as intermediate results in established eigen value programs for power systems, but not used further, are given a new interpretation. The effect of virtually any control action can be assessed based on a single eigenvalue-eigenvector calculation. In particular, the effect of active and reactive power modulation can be found as a multiplication of two or three complex numbers. The method is illustrated in an example for a large power system when applied to the control design for an HVDC-link.

  9. Energy Consumption Monitoring System for Large Complexes

    NASA Astrophysics Data System (ADS)

    Jorge, André; Guerreiro, João; Pereira, Pedro; Martins, João; Gomes, Luís

    This paper describes the development of an open source system for monitoring and data acquisition of several energy analyzers. The developed system is based on a computer with Internet/Intranet connection by means of RS485 using Modbus RTU as communication protocol. The monitoring/metering system was developed for large building complexes and was validated in the Faculdade de Ciências e Tecnologia University campus. The system considers two distinct applications. The first one allows the user to verify, in real time, the energy consumption of any department in the complex, produce load diagrams, tables and print, email or save all available data. The second application keeps records of active/reactive energy consumption in order to verify the existence of some anomalous situation, and also monthly charge energy consumption to each corresponding department.

  10. Compressed state Kalman filter for large systems

    NASA Astrophysics Data System (ADS)

    Kitanidis, Peter K.

    2015-02-01

    The Kalman filter (KF) is a recursive filter that allows the assimilation of data in real time and has found numerous applications. In earth sciences, the method is applied to systems with very large state vectors obtained from the discretization of functions such as pressure, velocity, solute concentration, and voltage. With state dimension running in the millions, the implementation of the standard or textbook version of KF is very expensive and low-rank approximations have been devised such as EnKF and SEEK. Although widely applied, the error behavior of these methods is not adequately understood. This article focuses on very large linear systems and presents a complete computational method that scales roughly linearly with the dimension of the state vector. The method is suited for problems for which the effective rank of the state covariance matrix is much smaller than its dimension. This method is closest to SEEK but uses a fixed basis that should be selected in accordance with the characteristics of the problem, mainly the transition matrix and the system noise covariance. The method is matrix free, i.e., does not require computation of Jacobian matrices and uses the forward model as a black box. Computational results demonstrate the ability of the method to solve very large, say 106 , state vectors.

  11. Numerical Modeling for Large Scale Hydrothermal System

    NASA Astrophysics Data System (ADS)

    Sohrabi, Reza; Jansen, Gunnar; Malvoisin, Benjamin; Mazzini, Adriano; Miller, Stephen A.

    2017-04-01

    Moderate-to-high enthalpy systems are driven by multiphase and multicomponent processes, fluid and rock mechanics, and heat transport processes, all of which present challenges in developing realistic numerical models of the underlying physics. The objective of this work is to present an approach, and some initial results, for modeling and understanding dynamics of the birth of large scale hydrothermal systems. Numerical modeling of such complex systems must take into account a variety of coupled thermal, hydraulic, mechanical and chemical processes, which is numerically challenging. To provide first estimates of the behavior of this deep complex systems, geological structures must be constrained, and the fluid dynamics, mechanics and the heat transport need to be investigated in three dimensions. Modeling these processes numerically at adequate resolution and reasonable computation times requires a suite of tools that we are developing and/or utilizing to investigate such systems. Our long-term goal is to develop 3D numerical models, based on a geological models, which couples mechanics with the hydraulics and thermal processes driving hydrothermal system. Our first results from the Lusi hydrothermal system in East Java, Indonesia provide a basis for more sophisticated studies, eventually in 3D, and we introduce a workflow necessary to achieve these objectives. Future work focuses with the aim and parallelization suitable for High Performance Computing (HPC). Such developments are necessary to achieve high-resolution simulations to more fully understand the complex dynamics of hydrothermal systems.

  12. Photovoltaic (PV) Pricing Trends: Historical, Recent, and Near-Term Projections

    SciTech Connect

    Feldman, David; Barbose, Galen; Margolis, Robert; Wiser, Ryan; Darghouth, Naim; Goodrich, Alan

    2012-11-30

    The installed capacity of global and U.S. photovoltaic (PV) systems has soared in recent years, driven by declining PV prices and government incentives. The U.S. Department of Energy’s (DOE) SunShot Initiative aims to make PV cost competitive without incentives by reducing the cost of PV-generated electricity by about 75% between 2010 and 2020. This summary report—based on research at Lawrence Berkeley National Laboratory (LBNL) and the National Renewable Energy Laboratory (NREL)—examines progress in PV price reductions to help DOE and other PV stakeholders manage the transition to a market-driven PV industry, and to provide clarity surrounding the wide variety of potentially conflicting data available about PV system prices.

  13. Cryogenic systems for the large deployable reflector

    NASA Technical Reports Server (NTRS)

    Mason, Peter V.

    1988-01-01

    There are five technologies which may have application for Large Deployable Reflector (LDR), one passive and four active. In order of maturity, they are passive stored cryogen systems, and mechanical, sorption, magnetic, and pulse-tube refrigerators. In addition, deep space radiators will be required to reject the heat of the active systems, and may be useful as auxiliary coolers for the stored cryogen systems. Hybrid combinations of these technologies may well be more efficient than any one alone, and extensive system studies will be required to determine the best trade-offs. Stored cryogen systems were flown on a number of missions. The systems are capable of meeting the temperature requirements of LDR. The size and weight of stored cryogen systems are proportional to heat load and, as a result, are applicable only if the low-temperature heat load can be kept small. Systems using chemisorption and physical adsorption for compressors and pumps have received considerable attention in the past few years. Systems based on adiabatic demagnetization of paramagnetic salts were used for refrigeration for many years. Pulse-tube refrigerators were recently proposed which show relatively high efficiency for temperatures in the 60 to 80 K range. The instrument heat loads and operating temperatures are critical to the selection and design of the cryogenic system. Every effort should be made to minimize heat loads, raise operating temperatures, and to define these precisely. No one technology is now ready for application to LDR. Substantial development efforts are underway in all of the technologies and should be monitored and advocated. Magnetic and pulse-tube refrigerators have high potential.

  14. Engineering management of large scale systems

    NASA Technical Reports Server (NTRS)

    Sanders, Serita; Gill, Tepper L.; Paul, Arthur S.

    1989-01-01

    The organization of high technology and engineering problem solving, has given rise to an emerging concept. Reasoning principles for integrating traditional engineering problem solving with system theory, management sciences, behavioral decision theory, and planning and design approaches can be incorporated into a methodological approach to solving problems with a long range perspective. Long range planning has a great potential to improve productivity by using a systematic and organized approach. Thus, efficiency and cost effectiveness are the driving forces in promoting the organization of engineering problems. Aspects of systems engineering that provide an understanding of management of large scale systems are broadly covered here. Due to the focus and application of research, other significant factors (e.g., human behavior, decision making, etc.) are not emphasized but are considered.

  15. Control theoretics for large structural systems

    NASA Technical Reports Server (NTRS)

    Montgomery, R. C.

    1981-01-01

    The areas of research addressed include modeling identification for both the purposes of analysis and controls, design of structural control systems actuator sensor placement, and distributed sensing and actuation as opposed to co-located sensor and actuators. Also investigated are adaptive/learning processes that could more specifically be referred to as inflight testing procedures where a structure is tested during its deployment or assembly and during its orbital life at specific points where the characteristics of the structure for the purpose of tuning the control system are identified. Another area is redundancy management techniques for structural systems. This is important because of the reliability issue for managing multiple very large numbers of sensors and actuators.

  16. System for inspecting large size structural components

    DOEpatents

    Birks, Albert S.; Skorpik, James R.

    1990-01-01

    The present invention relates to a system for inspecting large scale structural components such as concrete walls or the like. The system includes a mobile gamma radiation source and a mobile gamma radiation detector. The source and detector are constructed and arranged for simultaneous movement along parallel paths in alignment with one another on opposite sides of a structural component being inspected. A control system provides signals which coordinate the movements of the source and detector and receives and records the radiation level data developed by the detector as a function of source and detector positions. The radiation level data is then analyzed to identify areas containing defects corresponding to unexpected variations in the radiation levels detected.

  17. Recognition of error symptoms in large systems

    NASA Technical Reports Server (NTRS)

    Iyer, Ravishankar K.; Sridhar, V.

    1987-01-01

    A methodology for automatically detecting symptoms of frequently occurring errors in large computer systems is developed. The proposed symptom recognition methodology and its validation are based on probabilistic techniques. The technique is shown to work on real failure data from two CYBER systems at the University of Illinois. The methodology allows for the resolution between independent and dependent causes and, also quantifies a measure of the strength of relationship among errors. Comparison made with failure/repair information obtained from field maintenance engineers shows that in 85% of the cases, the error symptoms recognized by our approach correspond to real system problems. Further, the remaining 15% although not directly supported by field data, were confirmed as valid problems. Some of these were shown to be persistent problems which otherwise would have been considered as minor transients and hence ignored.

  18. The xylan utilization system of the plant pathogen Xanthomonas campestris pv campestris controls epiphytic life and reveals common features with oligotrophic bacteria and animal gut symbionts.

    PubMed

    Déjean, Guillaume; Blanvillain-Baufumé, Servane; Boulanger, Alice; Darrasse, Armelle; Dugé de Bernonville, Thomas; Girard, Anne-Laure; Carrére, Sébastien; Jamet, Stevie; Zischek, Claudine; Lautier, Martine; Solé, Magali; Büttner, Daniela; Jacques, Marie-Agnès; Lauber, Emmanuelle; Arlat, Matthieu

    2013-05-01

    Xylan is a major structural component of plant cell wall and the second most abundant plant polysaccharide in nature. Here, by combining genomic and functional analyses, we provide a comprehensive picture of xylan utilization by Xanthomonas campestris pv campestris (Xcc) and highlight its role in the adaptation of this epiphytic phytopathogen to the phyllosphere. The xylanolytic activity of Xcc depends on xylan-deconstruction enzymes but also on transporters, including two TonB-dependent outer membrane transporters (TBDTs) which belong to operons necessary for efficient growth in the presence of xylo-oligosaccharides and for optimal survival on plant leaves. Genes of this xylan utilization system are specifically induced by xylo-oligosaccharides and repressed by a LacI-family regulator named XylR. Part of the xylanolytic machinery of Xcc, including TBDT genes, displays a high degree of conservation with the xylose-regulon of the oligotrophic aquatic bacterium Caulobacter crescentus. Moreover, it shares common features, including the presence of TBDTs, with the xylan utilization systems of Bacteroides ovatus and Prevotella bryantii, two gut symbionts. These similarities and our results support an important role for TBDTs and xylan utilization systems for bacterial adaptation in the phyllosphere, oligotrophic environments and animal guts.

  19. TRNSYS HYBRID wind diesel PV simulator

    SciTech Connect

    Quinlan, P.J.A.; Mitchell, J.W.; Klein, S.A.; Beckman, W.A.; Blair, N.J.

    1996-12-31

    The Solar Energy Laboratory (SEL) has developed a wind diesel PV hybrid systems simulator, UW-HYBRID 1.0, an application of the TRNSYS 14.2 time-series simulation environment. An AC/DC bus links up to five diesels and wind turbine models, along with PV modules, a battery bank, and an AC/DC converter. Multiple units can be selected. PV system simulations include solar angle and peak power tracking options. Weather data are Typical Meteorological Year data, parametrically generated synthesized data, or external data files. PV performance simulations rely on long-standing SEL-developed algorithms. Loads data are read as scalable time series. Diesel simulations include estimated fuel-use and waste heat output, and are dispatched using a least-cost of fuel strategy. Wind system simulations include varying air density, wind shear and wake effects. Time step duration is user-selectable. UW-HYBRID 1.0 runs in Windows{reg_sign}, with TRNSED providing a customizable user interface. 12 refs., 6 figs.

  20. Large-scale structural monitoring systems

    NASA Astrophysics Data System (ADS)

    Solomon, Ian; Cunnane, James; Stevenson, Paul

    2000-06-01

    Extensive structural health instrumentation systems have been installed on three long-span cable-supported bridges in Hong Kong. The quantities measured include environment and applied loads (such as wind, temperature, seismic and traffic loads) and the bridge response to these loadings (accelerations, displacements, and strains). Measurements from over 1000 individual sensors are transmitted to central computing facilities via local data acquisition stations and a fault- tolerant fiber-optic network, and are acquired and processed continuously. The data from the systems is used to provide information on structural load and response characteristics, comparison with design, optimization of inspection, and assurance of continued bridge health. Automated data processing and analysis provides information on important structural and operational parameters. Abnormal events are noted and logged automatically. Information of interest is automatically archived for post-processing. Novel aspects of the instrumentation system include a fluid-based high-accuracy long-span Level Sensing System to measure bridge deck profile and tower settlement. This paper provides an outline of the design and implementation of the instrumentation system. A description of the design and implementation of the data acquisition and processing procedures is also given. Examples of the use of similar systems in monitoring other large structures are discussed.

  1. Accurate methods for large molecular systems.

    PubMed

    Gordon, Mark S; Mullin, Jonathan M; Pruitt, Spencer R; Roskop, Luke B; Slipchenko, Lyudmila V; Boatz, Jerry A

    2009-07-23

    Three exciting new methods that address the accurate prediction of processes and properties of large molecular systems are discussed. The systematic fragmentation method (SFM) and the fragment molecular orbital (FMO) method both decompose a large molecular system (e.g., protein, liquid, zeolite) into small subunits (fragments) in very different ways that are designed to both retain the high accuracy of the chosen quantum mechanical level of theory while greatly reducing the demands on computational time and resources. Each of these methods is inherently scalable and is therefore eminently capable of taking advantage of massively parallel computer hardware while retaining the accuracy of the corresponding electronic structure method from which it is derived. The effective fragment potential (EFP) method is a sophisticated approach for the prediction of nonbonded and intermolecular interactions. Therefore, the EFP method provides a way to further reduce the computational effort while retaining accuracy by treating the far-field interactions in place of the full electronic structure method. The performance of the methods is demonstrated using applications to several systems, including benzene dimer, small organic species, pieces of the alpha helix, water, and ionic liquids.

  2. Impact of residential PV adoption on Retail Electricity Rates

    SciTech Connect

    Cai, DWH; Adlakha, S; Low, SH; De Martini, P; Chandy, KM

    2013-11-01

    The price of electricity supplied from home rooftop photo voltaic (PV) solar cells has fallen below the retail price of grid electricity in some areas. A number of residential households have an economic incentive to install rooftop PV systems and reduce their purchases of electricity from the grid. A significant portion of the costs incurred by utility companies are fixed costs which must be recovered even as consumption falls. Electricity rates must increase in order for utility companies to recover fixed costs from shrinking sales bases. Increasing rates will, in turn, result in even more economic incentives for customers to adopt rooftop PV. In this paper, we model this feedback between PV adoption and electricity rates and study its impact on future PV penetration and net-metering costs. We find that the most important parameter that determines whether this feedback has an effect is the fraction of customers who adopt PV in any year based solely on the money saved by doing so in that year, independent of the uncertainties of future years. These uncertainties include possible changes in rate structures such as the introduction of connection charges, the possibility of PV prices dropping significantly in the future, possible changes in tax incentives, and confidence in the reliability and maintainability of PV. (C) 2013 Elsevier Ltd. All rights reserved.

  3. PV Cephei: Young Star Caught Speeding?

    NASA Astrophysics Data System (ADS)

    Goodman, Alyssa A.; Arce, Héctor G.

    2004-06-01

    Three independent lines of evidence imply that the young star PV Cep is moving at roughly 20 km s-1 through the interstellar medium. The first and strongest suggestion of motion comes from the geometry of the Herbig-Haro (HH) knots in the ``giant'' HH flow associated with PV Cep. Bisectors of lines drawn between pairs of knots at nearly equal distances from PV Cep imply an east-west motion of the source, and a plasmon model fitted to the knot positions gives a good fit of 22 km s-1 motion for the star. The second bit of damning evidence comes from a redshifted trail of molecular gas pointing in the same east-west direction implied by the HH knot geometry. The third exhibit we offer in accusing PV Cep of speeding involves the apparent tilt in the high-velocity molecular jet now emanating from the star. This tilt is best explained if the true, current jet direction is north-south, as it is in Hubble Space Telescope WFPC2 images, and the star is moving, again at roughly 20 km s-1. Tracing the motion of PV Cep backward in time to the nearest cluster from which it might have been ejected, we find that it is very likely to have been thrown out of the massive star-forming cluster NGC 7023, more than 10 pc away. PV Cep and NGC 7023 are at similar distances, and the backward trace of PV Cep's motion is astonishingly well aligned with a dark, previously unexplained rift in NGC 7023. We propose that PV Cep was ejected, at a speed large enough to escape NGC 7023, at least 100,000 yr ago but that it did not enter the molecular cloud in which it now finds itself until more like 35,000 yr ago. Our calculations show that the currently observable molecular outflow associated with PV Cep is about 10,000 yr old, so the flow has had plenty of time to form while in its current molecular cloud. However, the question of what PV Cep was doing and what gas/disk it took along with it in the time it was traveling through the low-density region between NGC 7023 and its current home is an open

  4. PV Ceph: Young Star Caught Speeding?

    NASA Astrophysics Data System (ADS)

    Goodman, A. A.; Arce, H. G.

    2003-12-01

    Three independent lines of evidence imply that the young star PV Ceph is moving at roughly 20 km s-1 through the interstellar medium. The first, and strongest, suggestion of motion comes from the geometry of the HH knots in the ``giant" Herbig-Haro flow associated with PV Ceph. Bisectors of lines drawn between pairs of knots at nearly equal distances from PV Ceph imply an E-W motion of the source, and a plasmon model fit to the knot positions gives a good fit of 22 km s-1 motion for the star. The second bit of damning evidence comes from a redshifted ``trail" of molecular gas, pointing in the same E-W direction implied by the HH knot geometry. The third exhibit we offer in accusing PV Ceph of speeding involves the tilt apparent in the high-velocity molecular jet now emanating from the star. This tilt is best explained if the true, current, jet direction is N-S, as it is in HST WFPC images, and the star is moving--again at roughly 20 km s-1. Tracing the motion of PV Ceph backward in time, to the nearest cluster from which it might have been ejected, we find that it is very likely to have been thrown out of the massive star-forming cluster NGC7023--more than 10 pc away. PV Ceph and NGC7023 are at similar distances, and the backward-trace of PV Ceph's motion is astonishingly well-aligned with a dark, previously unexplained, rift in NGC7023. We propose that PV Ceph was ejected, at a speed large enough to escape NGC7023, at least 100,000 years ago, but that it did not enter the molecular cloud in which it now finds itself until more like 10,000 years ago. Our calculations show that currently-observable molecular outflow associated with PV Ceph is about 10,000 years old, so that the flow has had plenty of time to form while in its current molecular cloud. But, the question of what PV Ceph was doing, and what gas/disk it took along with it in the time it was traveling through the low-density region between NGC7023 and its current home is open to question. Recent numerical

  5. Interband cascade (IC) photovoltaic (PV) architecture for PV devices

    DOEpatents

    Yang, Rui Q.; Tian, Zhaobing; Mishima, Tetsuya D.; Santos, Michael B.; Johnson, Matthew B.; Klem, John F.

    2015-10-20

    A photovoltaic (PV) device, comprising a PV interband cascade (IC) stage, wherein the IC PV stage comprises an absorption region with a band gap, the absorption region configured to absorb photons, an intraband transport region configured to act as a hole barrier, and an interband tunneling region configured to act as an electron barrier. An IC PV architecture for a photovoltaic device, the IC PV architecture comprising an absorption region, an intraband transport region coupled to the absorption region, and an interband tunneling region coupled to the intraband transport region and to the adjacent absorption region, wherein the absorption region, the intraband transport region, and the interband tunneling region are positioned such that electrons will flow from the absorption region to the intraband transport region to the interband tunneling region.

  6. Studies of solar photovoltaic/electrolytic hydrogen systems

    NASA Astrophysics Data System (ADS)

    Ogden, Joan M.

    1992-12-01

    Hydrogen is a high quality, low polluting fuel, which could replace oil and natural gas for transportation, heating, and power generation. If hydrogen is generated via solar photovoltaic (PV) powered water electrolysis, it would be possible to produce and use energy on a large scale with essentially no greenhouse gas emission and very little local pollution. In previous studies, we investigated some of the implications of projected advances in thin film PV technologies for PV hydrogen production. Here we summarize our findings on the design and economics of PV hydrogen systems, and discuss potential long term applications of PV hydrogen as a transportation fuel for ``zero emissions'' fuel cell vehicles.

  7. Large scale cryogenic fluid systems testing

    NASA Technical Reports Server (NTRS)

    1992-01-01

    NASA Lewis Research Center's Cryogenic Fluid Systems Branch (CFSB) within the Space Propulsion Technology Division (SPTD) has the ultimate goal of enabling the long term storage and in-space fueling/resupply operations for spacecraft and reusable vehicles in support of space exploration. Using analytical modeling, ground based testing, and on-orbit experimentation, the CFSB is studying three primary categories of fluid technology: storage, supply, and transfer. The CFSB is also investigating fluid handling, advanced instrumentation, and tank structures and materials. Ground based testing of large-scale systems is done using liquid hydrogen as a test fluid at the Cryogenic Propellant Tank Facility (K-site) at Lewis' Plum Brook Station in Sandusky, Ohio. A general overview of tests involving liquid transfer, thermal control, pressure control, and pressurization is given.

  8. Large Scale CW ECRH Systems: Some considerations

    NASA Astrophysics Data System (ADS)

    Erckmann, V.; Kasparek, W.; Plaum, B.; Lechte, C.; Petelin, M. I.; Braune, H.; Gantenbein, G.; Laqua, H. P.; Lubiako, L.; Marushchenko, N. B.; Michel, G.; Turkin, Y.; Weissgerber, M.

    2012-09-01

    Electron Cyclotron Resonance Heating (ECRH) is a key component in the heating arsenal for the next step fusion devices like W7-X and ITER. These devices are equipped with superconducting coils and are designed to operate steady state. ECRH must thus operate in CW-mode with a large flexibility to comply with various physics demands such as plasma start-up, heating and current drive, as well as configurationand MHD - control. The request for many different sophisticated applications results in a growing complexity, which is in conflict with the request for high availability, reliability, and maintainability. `Advanced' ECRH-systems must, therefore, comply with both the complex physics demands and operational robustness and reliability. The W7-X ECRH system is the first CW- facility of an ITER relevant size and is used as a test bed for advanced components. Proposals for future developments are presented together with improvements of gyrotrons, transmission components and launchers.

  9. Performance evaluation of stand alone hybrid PV-wind generator

    NASA Astrophysics Data System (ADS)

    Nasir, M. N. M.; Saharuddin, N. Z.; Sulaima, M. F.; Jali, Mohd Hafiz; Bukhari, W. M.; Bohari, Z. H.; Yahaya, M. S.

    2015-05-01

    This paper presents the performance evaluation of standalone hybrid system on Photovoltaic (PV)-Wind generator at Faculty of Electrical Engineering (FKE), UTeM. The hybrid PV-Wind in UTeM system is combining wind turbine system with the solar system and the energy capacity of this hybrid system can generate up to charge the battery and supply the LED street lighting load. The purpose of this project is to evaluate the performance of PV-Wind hybrid generator. Solar radiation meter has been used to measure the solar radiation and anemometer has been used to measure the wind speed. The effectiveness of the PV-Wind system is based on the various data that has been collected and compared between them. The result shows that hybrid system has greater reliability. Based on the solar result, the correlation coefficient shows strong relationship between the two variables of radiation and current. The reading output current followed by fluctuate of solar radiation. However, the correlation coefficient is shows moderate relationship between the two variables of wind speed and voltage. Hence, the wind turbine system in FKE show does not operate consistently to produce energy source for this hybrid system compare to PV system. When the wind system does not fully operate due to inconsistent energy source, the other system which is PV will operate and supply the load for equilibrate the extra load demand.

  10. Performance evaluation of stand alone hybrid PV-wind generator

    SciTech Connect

    Nasir, M. N. M.; Saharuddin, N. Z.; Sulaima, M. F.; Jali, Mohd Hafiz; Bukhari, W. M.; Bohari, Z. H.; Yahaya, M. S.

    2015-05-15

    This paper presents the performance evaluation of standalone hybrid system on Photovoltaic (PV)-Wind generator at Faculty of Electrical Engineering (FKE), UTeM. The hybrid PV-Wind in UTeM system is combining wind turbine system with the solar system and the energy capacity of this hybrid system can generate up to charge the battery and supply the LED street lighting load. The purpose of this project is to evaluate the performance of PV-Wind hybrid generator. Solar radiation meter has been used to measure the solar radiation and anemometer has been used to measure the wind speed. The effectiveness of the PV-Wind system is based on the various data that has been collected and compared between them. The result shows that hybrid system has greater reliability. Based on the solar result, the correlation coefficient shows strong relationship between the two variables of radiation and current. The reading output current followed by fluctuate of solar radiation. However, the correlation coefficient is shows moderate relationship between the two variables of wind speed and voltage. Hence, the wind turbine system in FKE show does not operate consistently to produce energy source for this hybrid system compare to PV system. When the wind system does not fully operate due to inconsistent energy source, the other system which is PV will operate and supply the load for equilibrate the extra load demand.

  11. Large-scale neuromorphic computing systems

    NASA Astrophysics Data System (ADS)

    Furber, Steve

    2016-10-01

    Neuromorphic computing covers a diverse range of approaches to information processing all of which demonstrate some degree of neurobiological inspiration that differentiates them from mainstream conventional computing systems. The philosophy behind neuromorphic computing has its origins in the seminal work carried out by Carver Mead at Caltech in the late 1980s. This early work influenced others to carry developments forward, and advances in VLSI technology supported steady growth in the scale and capability of neuromorphic devices. Recently, a number of large-scale neuromorphic projects have emerged, taking the approach to unprecedented scales and capabilities. These large-scale projects are associated with major new funding initiatives for brain-related research, creating a sense that the time and circumstances are right for progress in our understanding of information processing in the brain. In this review we present a brief history of neuromorphic engineering then focus on some of the principal current large-scale projects, their main features, how their approaches are complementary and distinct, their advantages and drawbacks, and highlight the sorts of capabilities that each can deliver to neural modellers.

  12. Kauai Island Utility Co-op (KIUC) PV integration study.

    SciTech Connect

    Ellis, Abraham; Mousseau, Tom

    2011-08-01

    This report investigates the effects that increased distributed photovoltaic (PV) generation would have on the Kauai Island Utility Co-op (KIUC) system operating requirements. The study focused on determining reserve requirements needed to mitigate the impact of PV variability on system frequency, and the impact on operating costs. Scenarios of 5-MW, 10-MW, and 15-MW nameplate capacity of PV generation plants distributed across the Kauai Island were considered in this study. The analysis required synthesis of the PV solar resource data and modeling of the KIUC system inertia. Based on the results, some findings and conclusions could be drawn, including that the selection of units identified as marginal resources that are used for load following will change; PV penetration will displace energy generated by existing conventional units, thus reducing overall fuel consumption; PV penetration at any deployment level is not likely to reduce system peak load; and increasing PV penetration has little effect on load-following reserves. The study was performed by EnerNex under contract from Sandia National Laboratories with cooperation from KIUC.

  13. Optimal Solar PV Arrays Integration for Distributed Generation

    SciTech Connect

    Omitaomu, Olufemi A; Li, Xueping

    2012-01-01

    Solar photovoltaic (PV) systems hold great potential for distributed energy generation by installing PV panels on rooftops of residential and commercial buildings. Yet challenges arise along with the variability and non-dispatchability of the PV systems that affect the stability of the grid and the economics of the PV system. This paper investigates the integration of PV arrays for distributed generation applications by identifying a combination of buildings that will maximize solar energy output and minimize system variability. Particularly, we propose mean-variance optimization models to choose suitable rooftops for PV integration based on Markowitz mean-variance portfolio selection model. We further introduce quantity and cardinality constraints to result in a mixed integer quadratic programming problem. Case studies based on real data are presented. An efficient frontier is obtained for sample data that allows decision makers to choose a desired solar energy generation level with a comfortable variability tolerance level. Sensitivity analysis is conducted to show the tradeoffs between solar PV energy generation potential and variability.

  14. Iron-regulated metabolites produced by Pseudomonas fluorescens WCS374r are not required for eliciting induced systemic resistance against Pseudomonas syringae pv. tomato in Arabidopsis.

    PubMed

    Djavaheri, Mohammad; Mercado-Blanco, Jesús; Versluis, C; Meyer, J-M; Loon, L C; Bakker, Peter A H M

    2012-09-01

    The plant growth-promoting rhizobacterium Pseudomonas fluorescens WCS374r produces several iron-regulated metabolites, including the fluorescent siderophore pseudobactin (Psb374), salicylic acid (SA), and pseudomonine (Psm), a siderophore that contains a SA moiety. After purification of Psb374 from culture supernatant of WCS374r, its structure was determined following isoelectrofocusing and tandem mass spectrometry, and found to be identical to the fluorescent siderophore produced by P. fluorescens ATCC 13525. To study the role of SA and Psm production in colonization of Arabidopsis thaliana roots and in induced systemic resistance (ISR) against Pseudomonas syringae pv. tomato (Pst) by strain WCS374r, mutants disrupted in the production of these metabolites were obtained by homologous recombination. These mutants were further subjected to transposon Tn5 mutagenesis to generate mutants also deficient in Psb374 production. The mutants behaved similar to the wild type in both their Arabidopsis rhizosphere-colonizing capacity and their ability to elicit ISR against Pst. We conclude that Psb374, SA, and Psm production by P. fluorescens WCS374r are not required for eliciting ISR in Arabidopsis.

  15. Two overlapping two-component systems in Xanthomonas oryzae pv. oryzae contribute to full fitness in rice by regulating virulence factors expression

    PubMed Central

    Zheng, Dehong; Yao, Xiaoyan; Duan, Meng; Luo, Yufeng; Liu, Biao; Qi, Pengyuan; Sun, Ming; Ruan, Lifang

    2016-01-01

    Two-component signal transduction systems (TCSs) are widely used by bacteria to adapt to the environment. In the present study, StoS (stress tolerance-related oxygen sensor) and SreKRS (salt response kinase, regulator, and sensor) were found to positively regulate extracellular polysaccharide (EPS) production and swarming in the rice pathogen Xanthomonas oryzae pv. oryzae (Xoo). Surprisingly, the absence of stoS or sreKRS did not attenuate virulence. To better understand the intrinsic functions of StoS and SreKRS, quantitative proteomics isobaric tags for relative and absolute quantitation (iTRAQ) was employed. Consistent with stoS and sreK mutants exhibiting a similar phenotype, the signalling circuits of StoS and SreKRS overlapped. Carbohydrate metabolism proteins and chemotaxis proteins, which could be responsible for EPS and swarming regulation, respectively, were reprogrammed in stoS and sreK mutants. Moreover, StoS and SreKRS demonstrated moderate expression of the major virulence factor, hypersensitive response and pathogenicity (Hrp) proteins through the HrpG-HrpX circuit. Most importantly, Xoo equipped with StoS and SreKRS outcompetes strains without StoS or SreKRS in co-infected rice and grows outside the host. Therefore, we propose that StoS and SreKRS adopt a novel strategy involving the moderation of Hrp protein expression and the promotion of EPS and motility to adapt to the environment. PMID:26957113

  16. Large-Scale PV Module Manufacturing Using Ultra-Thin Polycrystalline Silicon Solar Cells: Final Subcontract Report, 1 April 2002--28 February 2006

    SciTech Connect

    Wohlgemuth, J.; Narayanan, M.

    2006-07-01

    The major objectives of this program were to continue advances of BP Solar polycrystalline silicon manufacturing technology. The Program included work in the following areas. (1) Efforts in the casting area to increase ingot size, improve ingot material quality, and improve handling of silicon feedstock as it is loaded into the casting stations. (2) Developing wire saws to slice 100-..mu..m-thick silicon wafers on 290-..mu..m-centers. (3) Developing equipment for demounting and subsequent handling of very thin silicon wafers. (4) Developing cell processes using 100-..mu..m-thick silicon wafers that produce encapsulated cells with efficiencies of at least 15.4% at an overall yield exceeding 95%. (5) Expanding existing in-line manufacturing data reporting systems to provide active process control. (6) Establishing a 50-MW (annual nominal capacity) green-field Mega-plant factory model template based on this new thin polycrystalline silicon technology. (7) Facilitating an increase in the silicon feedstock industry's production capacity for lower-cost solar-grade silicon feedstock..

  17. Integrating High Penetrations of PV into Southern California: Year 2 Project Update; Preprint

    SciTech Connect

    Mather, B.; Neal, R.

    2012-08-01

    Southern California Edison (SCE) is well into a five-year project to install a total of 500 MW of distributed photovoltaic (PV) energy within its utility service territory. Typical installations to date are 1-3 MW peak rooftop PV systems that interconnect to medium-voltage urban distribution circuits or larger (5 MW peak) ground-mounted systems that connect to medium-voltage rural distribution circuits. Some of the PV system interconnections have resulted in distribution circuits that have a significant amount of PV generation compared to customer load, resulting in high-penetration PV integration scenarios. The National Renewable Energy Laboratory (NREL) and SCE have assembled a team of distribution modeling, resource assessment, and PV inverter technology experts in order to investigate a few of the high-penetration PV distribution circuits. Currently, the distribution circuits being studied include an urban circuit with a PV penetration of approximately 46% and a rural circuit with a PV penetration of approximately 60%. In both cases, power flow on the circuit reverses direction, compared to traditional circuit operation, during periods of high PV power production and low circuit loading. Research efforts during year two of the five-year project were focused on modeling the distribution system level impacts of high-penetration PV integrations, the development and installation of distribution circuit data acquisition equipment appropriate for quantifying the impacts of high-penetration PV integrations, and investigating high-penetration PV impact mitigation strategies. This paper outlines these research efforts and discusses the following activities in more detail: the development of a quasi-static time-series test feeder for evaluating high-penetration PV integration modeling tools; the advanced inverter functions being investigated for deployment in the project's field demonstration and a power hardware-in-loop test of a 500-kW PV inverter implementing a

  18. Concomitant induction of systemic resistance to Pseudomonas syringae pv. lachrymans in cucumber by Trichoderma asperellum (T-203) and accumulation of phytoalexins.

    PubMed

    Yedidia, Iris; Shoresh, Michal; Kerem, Zohar; Benhamou, Nicole; Kapulnik, Yoram; Chet, Ilan

    2003-12-01

    Most studies on the reduction of disease incidence in soil treated with Trichoderma asperellum have focused on microbial interactions rather than on plant responses. This study presents conclusive evidence for the induction of a systemic response against angular leaf spot of cucumber (Pseudomonas syringae pv. lachrymans) following application of T. asperellum to the root system. To ascertain that T. asperellum was the only microorganism present in the root milieu, plants were grown in an aseptic hydroponic growth system. Disease symptoms were reduced by as much as 80%, corresponding to a reduction of 2 orders of magnitude in bacterial cell densities in leaves of plants pretreated with T. asperellum. As revealed by electron microscopy, bacterial cell proliferation in these plants was halted. The protection afforded by the biocontrol agent was associated with the accumulation of mRNA of two defense genes: the phenylpropanoid pathway gene encoding phenylalanine ammonia lyase (PAL) and the lipoxygenase pathway gene encoding hydroxyperoxide lyase (HPL). This was further supported by the accumulation of secondary metabolites of a phenolic nature that showed an increase of up to sixfold in inhibition capacity of bacterial growth in vitro. The bulk of the antimicrobial activity was found in the acid-hydrolyzed extract containing the phenolics in their aglycone form. High-performance liquid chromatography analysis of phenolic compounds showed a marked change in their profile in the challenged, preelicited plants relative to that in challenged controls. The results suggest that similar to beneficial rhizobacteria, T. asperellum may activate separate metabolic pathways in cucumber that are involved in plant signaling and biosynthesis, eventually leading to the systemic accumulation of phytoalexins.

  19. Automatic welding systems for large ship hulls

    NASA Astrophysics Data System (ADS)

    Arregi, B.; Granados, S.; Hascoet, JY.; Hamilton, K.; Alonso, M.; Ares, E.

    2012-04-01

    Welding processes represents about 40% of the total production time in shipbuilding. Although most of the indoor welding work is automated, outdoor operations still require the involvement of numerous operators. To automate hull welding operations is a priority in large shipyards. The objective of the present work is to develop a comprehensive welding system capable of working with several welding layers in an automated way. There are several difficulties for the seam tracking automation of the welding process. The proposed solution is the development of a welding machine capable of moving autonomously along the welding seam, controlling both the position of the torch and the welding parameters to adjust the thickness of the weld bead to the actual gap between the hull plates.

  20. The acyl-homoserine lactone-type quorum-sensing system modulates cell motility and virulence of Erwinia chrysanthemi pv. zeae.

    PubMed

    Hussain, Mumtaz B B M; Zhang, Hai-Bao; Xu, Jin-Ling; Liu, Qiongguang; Jiang, Zide; Zhang, Lian-Hui

    2008-02-01

    Erwinia chrysanthemi pv. zeae is one of the Erwinia chrysanthemi pathovars that infects on both dicotyledons and monocotyledons. However, little is known about the molecular basis and regulatory mechanisms of its virulence. By using a transposon mutagenesis approach, we cloned the genes coding for an E. chrysanthemi pv. zeae synthase of acyl-homoserine lactone (AHL) quorum-sensing signals (expI(Ecz)) and a cognate response regulator (expR(Ecz)). Chromatography analysis showed that expI(Ecz) encoded production of the AHL signal N-(3-oxo-hexanoyl)-homoserine lactone (OHHL). Null mutation of expI(Ecz) in the E. chrysanthemi pv. zeae strain EC1 abolished AHL production, increased bacterial swimming and swarming motility, disabled formation of multicell aggregates, and attenuated virulence of the pathogen on potato tubers. The mutation also marginally reduced the inhibitory activity of E. chrysanthemi pv. zeae on rice seed germination. The mutant phenotypes were rescued by either exogenous addition of AHL signal or in trans expression of expI(Ecz). These data demonstrate that the AHL-type QS signal plays an essential role in modulation of E. chrysanthemi pv. zeae cell motility and the ability to form multicell aggregates and is involved in regulation of bacterial virulence.

  1. P-V criticality in the extended phase-space of charged accelerating AdS black holes

    NASA Astrophysics Data System (ADS)

    Liu, Hang; Meng, Xin-He

    2016-11-01

    In this paper, we investigate the P-V criticality and phase transition of charged accelerating AdS black holes in the extended thermodynamic phase-space in analogy between black hole system and van der Waals liquid-gas system, where the cosmological constant Λ is treated as a thermodynamical variable interpreted as dynamic pressure and its conjugate quantity is the thermodynamic volume of the black holes. When the electric charge vanishes, we find that no P-V criticality will appear but the Hawking-Page-like phase transition will be present, just as what Schwarzschild-AdS black holes behave like. For the charged case, the P-V criticality appears and the accelerating black holes will undergo a small black hole/large phase transition under the condition that the acceleration parameter A and the horizon radius rh meet a certain simple relation Arh = a, where a is a constant in our discussion. To make P-V criticality appear, there exists an upper bounds for constant a. When P-V criticality appears, we calculate the critical pressure Pc, critical temperature Tc and critical specific volume rc, and we find that Pcrc Tc is an universal number.

  2. Improved methods for the measurement and modeling of PV module and system performance for all operating conditions

    SciTech Connect

    King, D.L.

    1995-11-01

    The objective of this work was to develop improved performance model for modules and systems for for all operating conditions for use in module specifications, system and BOS component design, and system rating or monitoring. The approach taken was to identify and quantify the influence of dominant factors of solar irradiance, cell temperature, angle-of-incidence; and solar spectrum; use outdoor test procedures to separate the effects of electrical, thermal, and optical performance; use fundamental cell characteristics to improve analysis; and combine factors in simple model using the common variables.

  3. Methods for high-voltage bias testing of PV modules in hot and humid climate

    NASA Astrophysics Data System (ADS)

    Dhere, Neelkanth G.; Pethe, Shirish A.; Kaul, Ashwani

    2011-09-01

    The accelerated tests currently carried out on PV modules reduce the infant mortality as well as improve the production techniques during the manufacture of PV modules. However, the accelerated tests do not completely duplicate the real world operating conditions of PV modules. Hence it is essential to deploy PV modules in the field for extended periods in order to estimate the degradation, if any, as well as to elucidate the degradation mechanisms. Moreover, PV modules should be tested by specially designed tests in harsh climates. At Florida Solar Energy Center (FSEC) high-voltage bias testing of PV modules was carried out in hot and humid climate with the individual modules biased at +/- 600 V. It was observed that the leakage currents flowing from the PV circuit to the ground is directly proportional to the bias voltage. PV systems with maximum voltage of 1000 V are installed in Europe and elsewhere which means higher leakage currents will be produced in the PV modules. Based on this fact and the earlier observations, high voltage bias testing of c-Si PV modules specially designed for high voltage operation was carried out in hot and humid climate with the individual modules biased at +/-1500 V at FSEC and higher. This paper provides results of high voltage bias testing of PV modules. The results indicate that the test can be considered as reliable metric in determination of the long term performance of PV modules.

  4. Magmatic systems of large continental igneous province

    NASA Astrophysics Data System (ADS)

    Sharkov, Evgenii

    2014-05-01

    Large igneous provinces (LIPs) of the modern type are known from the middle Paleoproterozoic and have a great abundance in the Phanerozoic. The most researches considered their appearance with ascending of the mantle thermochemical superplumes which provided simultaneously eruption of the same type of lavas on the huge territories. Judging on presence among them different subprovinces, formation of concrete magmatic systems were linked with protuberances (secondary plumes) on the superplumes surfaces. We suggest that origin of such plumes was linked with local enrichment of upper part of the superplumes head beneath roofing by fluid components; it led to lowering of the plume material density and initiated ascending of the secondary plumes. As a result, their heads, where partial melting occurred, can reach the level of the upper crust as it follows from absence of lower-crustal rocks among xenoliths in basalts, although mantle xenoliths existed in them. Important feature of LIPs is presence of two major types of mafic lavas: (1) geochemical-enriched alkali Fe-Ti basalts and picrites, and (2) basalts of normal alkalinity (tholeiites) with different contents of TiO2. At that the first type of mafites are usually typical for lower parts of LIPs which initially developed as continental rifts, whereas the second type composed the upper part of the traps' cover. Magmatic systems of the LIPs are subdivided on three levels of different deep: (1) zones of magma generation, (2) areas of transitional magma chambers where large often layered intrusive bodies are formed, and (3) areas on surface where lava eruptions and subvolcanic intrusions occurred. All these levels are linked by feeder dykes. The least known element of the system is area of magma generation, and, especially, composition of melting substratum. Important information about it is contained in aforementioned mantle xenoliths in alkali basalts and basanites. They practically everywhere are represented by two

  5. Detecting loss mechanisms of c-Si PV modules in-situ I-V measurement

    NASA Astrophysics Data System (ADS)

    Guo, Siyu; Schneller, Eric; Walters, Joe; Davis, Kristopher O.; Schoenfeld, Winston V.

    2016-09-01

    PV module reliability is alsways an important issue for PV industry. In an outdoor PV system, PV modules suffer from degradation due to different factors. It is then very important to determine the loss mechanisms of a PV module and making improvement based on this. It is found in this work that due to mismatch effect, using fitting method to extract I-V characteristics might not be well applied on a PV module, especially when it has non-uniform degradation problem. This work proposes a method to accurately quantify the power loss of PV modules due to different degradation mechanisms, including series resistance (Rs) loss, non-uniform shunting loss and number of shunted cells, uniform shunting loss, uniform current loss, non-uniform current (mismatch) loss, recombination current (J01 and J02) losses of a PV module. All required input information are the measured current-voltage (I-V) curves and short circuit current- open circuit voltage (Isc-Voc) of PV module initial state and final state. The method is first applied to a simulated PV module with various degradation problems. Power loss due to each loss mechanism for the simulated PV module is then extracted using the proposed method and a pie chart can be generated. Comparing with the actual power loss on each loss mechanism, the method proposed in this work is proved to be very accurate. The method is then further applied to a degradated PV module istalled in an outdoor PV system. The power loss on series resistance, shunting and current mismatch are effectively identified and the number of shunted cells is accurately calculated. In the real application, this method can be used in both indoor and outdoor characterization, which can be very beneficial for PV degradation analysis of PV modules and systems.

  6. Current Utility Screening Practices, Technical Tools, Impact Studies, and Mitigation Strategies for Interconnecting PV on the Electric Distribution Systems

    SciTech Connect

    Coddington, Michael

    2014-12-19

    This report summarizes common best practices of photovoltaic system interconnection procedures based on interviews held with 19 electric utilities located in the state of California and in the southwestern, central, and northeastern regions of the United States.

  7. 205 kW Photovoltaic (PV) System Installed on the U.S. Department of Energy's Forrestal Building

    SciTech Connect

    2009-01-18

    Fact sheet on the installation of a photovoltaic system providing renewable energy for the U.S. Department of Energy and providing leadership for meeting Federal goals in the use of renewable energy technologies.

  8. Salicylic Acid Mediated by the Oxidative Burst Is a Key Molecule in Local and Systemic Responses of Cotton Challenged by an Avirulent Race of Xanthomonas campestris pv malvacearum

    PubMed Central

    Martinez, Christelle; Baccou, Jean-Claude; Bresson, Estelle; Baissac, Yves; Daniel, Jean-François; Jalloul, Aïda; Montillet, Jean-Luc; Geiger, Jean-Paul; Assigbetsé, Komi; Nicole, Michel

    2000-01-01

    We analyzed the production of reactive oxygen species, the accumulation of salicylic acid (SA), and peroxidase activity during the incompatible interaction between cotyledons of the cotton (Gossypium hirsutum) cv Reba B50/Xanthomonas campestris pv malvacearum (Xcm) race 18. SA was detected in petioles of cotyledons 6 h after infection and 24 h post inoculation in cotyledons and untreated leaves. The first peak of SA occurred 3 h after generation of superoxide (O2·−), and was inhibited by infiltration of catalase. Peroxidase activity and accumulation of SA increased in petioles of cotyledons and leaves following H2O2 infiltration of cotyledons from 0.85 to 1 mm. Infiltration of 2 mm SA increased peroxidase activity in treated cotyledons and in the first leaves, but most of the infiltrated SA was rapidly conjugated within the cotyledons. When increasing concentrations of SA were infiltrated 2.5 h post inoculation at the beginning of the oxidative burst, the activity of the apoplastic cationic O2·−-generating peroxidase decreased in a dose-dependent manner. We have shown that during the cotton hypersensitive response to Xcm, H2O2 is required for local and systemic accumulation of SA, which may locally control the generation of O2·−. Detaching cotyledons at intervals after inoculation demonstrated that the signal leading to systemic accumulation of SA was emitted around 3 h post inoculation, and was associated with the oxidative burst. SA produced 6 h post infection at HR sites was not the primary mobile signal diffusing systemically from infected cotyledons. PMID:10712539

  9. Salicylic acid mediated by the oxidative burst is a key molecule in local and systemic responses of cotton challenged by an avirulent race of Xanthomonas campestris pv malvacearum.

    PubMed

    Martinez, C; Baccou, J C; Bresson, E; Baissac, Y; Daniel, J F; Jalloul, A; Montillet, J L; Geiger, J P; Assigbetsé, K; Nicole, M

    2000-03-01

    We analyzed the production of reactive oxygen species, the accumulation of salicylic acid (SA), and peroxidase activity during the incompatible interaction between cotyledons of the cotton (Gossypium hirsutum) cv Reba B50/Xanthomonas campestris pv malvacearum (Xcm) race 18. SA was detected in petioles of cotyledons 6 h after infection and 24 h post inoculation in cotyledons and untreated leaves. The first peak of SA occurred 3 h after generation of superoxide (O(2)(.-)), and was inhibited by infiltration of catalase. Peroxidase activity and accumulation of SA increased in petioles of cotyledons and leaves following H(2)O(2) infiltration of cotyledons from 0.85 to 1 mM. Infiltration of 2 mM SA increased peroxidase activity in treated cotyledons and in the first leaves, but most of the infiltrated SA was rapidly conjugated within the cotyledons. When increasing concentrations of SA were infiltrated 2. 5 h post inoculation at the beginning of the oxidative burst, the activity of the apoplastic cationic O(2)(.-)-generating peroxidase decreased in a dose-dependent manner. We have shown that during the cotton hypersensitive response to Xcm, H(2)O(2) is required for local and systemic accumulation of SA, which may locally control the generation of O(2)(.-). Detaching cotyledons at intervals after inoculation demonstrated that the signal leading to systemic accumulation of SA was emitted around 3 h post inoculation, and was associated with the oxidative burst. SA produced 6 h post infection at HR sites was not the primary mobile signal diffusing systemically from infected cotyledons.

  10. Auxiliary propulsion requirements for large space systems

    NASA Technical Reports Server (NTRS)

    Maloy, J. E.; Smith, W. W.; Machles, G. W.

    1983-01-01

    An insight into auxiliary propulsion systems (APS) requirements for large space systems (LSS) launchable by a single shuttle is presented. In an effort to scope the APS requirements for LSS, a set of generic LSSs were defined. For each generic LSS class a specific structural configuration, representative of that most likely to serve the needs of the 1980's and 1990's was defined. The environmental disturbance forces and torques which would be acting on each specific structural configuration in LEO and GEO orbits were then determined. Auxiliary propulsion requirements were determined as a function of: generic class specific configuration, size and openness of structure, orbit, angle of orientation, correction frequency, duty cycle, number and location of thrusters and direction of thrusters and APS/LSS interactions. The results of this analysis were used to define the APS characteristics of: (1) number and distribution of thrusters, (2) thruster modulation, (3) thrust level, (4) mission energy requirements, (5) total APS mass component breakdown, and (6) state of the art adequacy/deficiency. Previously announced in STAR as N83-26922

  11. Auxiliary propulsion requirements for large space systems

    NASA Technical Reports Server (NTRS)

    Maloy, J. E.; Smith, W. W.; Machles, G. W.

    1983-01-01

    An insight into auxiliary propulsion systems (APS) requirements for large space systems (LSS) launchable by a single shuttle is presented. In an effort to scope the APS requirements for LSS, a set of generic LSSs were defined. For each generic LSS class a specific structural configuration, representative of that most likely to serve the needs of the 1980's and 1990's was defined. The environmental disturbance forces and torques which would be acting on each specific structural configuration in LEO and GEO orbits were then determined. Auxiliary propulsion requirements were determined as a function of: generic class specific configuration, size and openness of structure, orbit, angle of orientation, correction frequency, duty cycle, number and location of thrusters and direction of thrusters and APS/LSS interactions. The results of this analysis were used to define the APS characteristics of: (1) number and distribution of thrusters, (2) thruster modulation, (3) thrust level, (4) mission energy requirements, (5) total APS mass component breakdown, and (6) state of the art adequacy/deficiency.

  12. Contrasting freezeouts in large versus small systems

    NASA Astrophysics Data System (ADS)

    Chatterjee, Sandeep; Dash, Ajay Kumar; Mohanty, Bedangadas

    2017-10-01

    We study the data on mean hadron yields and contrast the chemical freezeout (CFO) conditions in p+p, p+Pb and Pb+Pb at the Large Hadron Collider energies. We study several schemes for freezeout that mainly differ in the way strangeness is treated: i. Strangeness freezes out along with the non-strange hadrons in complete equilibrium (1CFO), ii. Strangeness freezes out along with non-strange hadrons with an additional parameter {γ }S accounting for non-equilibrium production of strangeness (1CFO+{γ }S), and iii. Strangeness freezes out earlier than non-strange hadrons and in thermal equilibrium (2CFO). A comparison of the chisquares of the fits indicate a dependence of the freezeout scheme on the system size. The minimum bias p+p and different centralities of p+Pb and peripheral Pb+Pb data prefer 1CFO+{γ }S with {γ }S approaching unity as we go from p+p to central p+Pb and peripheral Pb+Pb. On the other hand, the mid-central to central Pb+Pb data prefer 2CFO over 1CFO+{γ }S. Such system size dependence of the freezeout scheme could be an indication of the additional interaction in Pb+Pb over p+Pb and p+p.

  13. Power quality enhancement of renewable energy source power network using SMES system

    NASA Astrophysics Data System (ADS)

    Seo, H. R.; Kim, A. R.; Park, M.; Yu, I. K.

    2011-11-01

    This paper deals with power quality enhancement of renewable energy source power network using SMES system and describes the operation characteristics of HTS SMES system using real-toroidal-type SMES coil for smoothening the fluctuation of large-scale renewable energy source such as photovoltaic (PV) power generation system. It generates maximum power of PV array under various weather conditions. SMES unit charges and discharges the HTS coil to mitigate the fluctuation of PV system output power. The SMES unit is controlled according to the PV array output and the utility power quality conditions. The grid connected PV and SMES system has been modeled and simulated using power-hard-in-the-loop simulation (PHILS). The PHILS results demonstrated the effectiveness of the SMES system for enhancing power quality in power network including large-scale renewable energy source, especially PV power generation system.

  14. Full Steam Ahead for PV in US Homes?

    SciTech Connect

    Bolinger, Mark A; Barbose, Galen; Wiser, Ryan

    2009-01-15

    In October 2008, the United States Congress extended both the residential and commercial solar investment tax credits (ITCs) for an unprecedented eight years, lifted the $2,000 cap on the residential credit, removed the prohibition on utility use of the commercial credit, and eliminated restrictions on the use of both credits in conjunction with the Alternative Minimum Tax. These significant changes, which apply to systems placed in service on or after January 1, 2009, will increase the value of the solar credits for residential system owners in particular, and are likely--in conjunction with state, local, and utility rebate programs targeting solar--to spur significant growth in residential, commercial, and utility-scale photovoltaic (PV) installations in the years ahead. This article focuses specifically on the residential credit, describing three areas in which removal of the $2,000 cap on the residential ITC will have significant implications for PV rebate program administrators, PV system owners, and the PV industry.

  15. The 1980 Large space systems technology. Volume 2: Base technology

    NASA Technical Reports Server (NTRS)

    Kopriver, F., III (Compiler)

    1981-01-01

    Technology pertinent to large antenna systems, technology related to large space platform systems, and base technology applicable to both antenna and platform systems are discussed. Design studies, structural testing results, and theoretical applications are presented with accompanying validation data. A total systems approach including controls, platforms, and antennas is presented as a cohesive, programmatic plan for large space systems.

  16. Calculated effect of central DC/AC power conversion from PV generators with different orientations

    SciTech Connect

    Weiden, T.C.J. van der; Kil, A.J.

    1994-12-31

    The energy production of two PV/inverter configurations for a grid connected PV system consisting of roof and facade integrated subarrays with five different orientations and tilt angles was predicted by computer simulations. These calculations show that the total DC energy production of the system is practically not affected if the subarrays have one central inverter and all operate at the same maximum power point. Application of one central inverter for such a system geometry may lead to a reduction of the specific kWh costs of approximately 4% due to lower specific costs and higher efficiency of large inverters and because the central inverter can be undersized to a larger extent than the 5 smaller inverters.

  17. A review of large wind turbine systems

    NASA Astrophysics Data System (ADS)

    Selzer, H.; Lerner, J. I.

    Research areas in the design and operation of large wind turbines in the U.S. and Europe are detailed, with attention given to current and completed programs. Theoretical work in the U.S. is focused on aerodynamics of blades, structural dynamics, control systems, and safety through safe life design, redundancy, and quality assurance. Work is continuing on wind characteristics over the rotor disk and design criteria with regard to cost/benefits and tradeoffs involving various configurations and materials for the rotor blades, placement, pitch control, blade articulation, the tower, the drive train, the gear box, a quill shaft, generator type, and reliability and maintenance. Costing models are being developed. Test experience has been gained through the manufacture and operation of the five Mod 0A, one Mod-1, four Mod-2, and one WTS-4 wind turbines. The European work on blade loading, wind turbine dimensioning, materials, wind structure, environmental impacts, and economics are reviewed, together with the operational experience with the Gedser, two Nibe, the Tvind, and Growian machines. Several countries are also testing smaller wind turbines manufactured indigenously or imported.

  18. Simulation and experimental design of a new advanced variable step size Incremental Conductance MPPT algorithm for PV systems.

    PubMed

    Loukriz, Abdelhamid; Haddadi, Mourad; Messalti, Sabir

    2016-05-01

    Improvement of the efficiency of photovoltaic system based on new maximum power point tracking (MPPT) algorithms is the most promising solution due to its low cost and its easy implementation without equipment updating. Many MPPT methods with fixed step size have been developed. However, when atmospheric conditions change rapidly , the performance of conventional algorithms is reduced. In this paper, a new variable step size Incremental Conductance IC MPPT algorithm has been proposed. Modeling and simulation of different operational conditions of conventional Incremental Conductance IC and proposed methods are presented. The proposed method was developed and tested successfully on a photovoltaic system based on Flyback converter and control circuit using dsPIC30F4011. Both, simulation and experimental design are provided in several aspects. A comparative study between the proposed variable step size and fixed step size IC MPPT method under similar operating conditions is presented. The obtained results demonstrate the efficiency of the proposed MPPT algorithm in terms of speed in MPP tracking and accuracy.

  19. Real-Time Series Resistance Monitoring in PV Systems Without the Need for I-V Curves

    SciTech Connect

    Deceglie, Michael G.; Silverman, Timothy J.; Marion, Bill; Kurtz, Sarah R.

    2015-10-01

    We apply the physical principles of a familiar method, suns-Voc, to a new application: the real-time detection of series resistance changes in modules and systems operating outside. The real-time series resistance (RTSR) method that we describe avoids the need for collecting I-V curves or constructing full series resistance-free I-V curves. RTSR is most readily deployable at the module level on microinverters or module-integrated electronics, but it can also be extended to full strings. We found that automated detection of series resistance increases can provide early warnings of some of the most common reliability issues, which also pose fire risks, including broken ribbons, broken solder bonds, and contact problems in the junction or combiner box. We also describe the method in detail and describe a sample application to data collected from modules operating in the field.

  20. Persistence and translocation of a benzothiadiazole derivative in tomato plants in relation to systemic acquired resistance against Pseudomonas syringae pv tomato.

    PubMed

    Scarponi, L; Buonaurio, R; Martinetti, L

    2001-03-01

    A reproducible and accurate procedure, based on HPLC analysis, has been developed to determine simultaneously acibenzolar-S-methyl (CGA 245 704) and its acid derivative (CGA 210 007) in tomato leaves. The limit of detection and quantification of the method are 0.015 and 0.15 mg litre-1 for CGA 245 704 and 0.030 and 0.30 mg litre-1 for CGA 210 007. In tomato plants treated with 250 microM CGA 245 704, it was found that the inducer rapidly translocates from treated leaves (cotyledons, 1st and 2nd) to untreated leaves (3rd to 5th), with the maximum translocation (40% of the total quantity found) occurring 8 h after the treatment. CGA 245 704 residues decreased as time elapsed in both treated and untreated tomato leaves, reaching negligible values 72 h after treatment. The acid derivative, CGA 210 007, was formed in tomato plants as early as 2 h after CGA 245 704 treatment, albeit only in the treated leaves. CGA 210 007 residues decreased in treated tomato leaves with a trend similar to that observed for CGA 245 704. Treatment of tomato plants with CGA 245 704 or CGA 210 007 at 250 microM systemically protected the plants against Pseudomonas syringae pv tomato attacks, the causal agent of bacterial speak disease. Evidence of this were reductions in the degree of infection, the bacterial lesion diameter and the bacterial growth in planta. Since neither CGA 245 704 nor CGA 210 007 inhibited bacterial growth in vitro and the protection against bacterial speak of tomato was observed when the two compounds were completely degraded, the protection must be due to the activation of the plant's defence mechanisms.

  1. Evaluation of the Performance of the PVUSA Rating Methodology Applied to Dual Junction PV Technology: Preprint (Revised)

    SciTech Connect

    Myers, D. R.

    2009-07-01

    The PVUSA (Photovoltaics for Utility Scale Applications) project in the 1990's developed a rating methodology for PV performance evaluation which has become popular, and even incorporated into concentrating PV rating standards This report apply that method to rack-mounted dual-junction PV system, and produces a system rating.

  2. Long Focal Length Large Mirror Fabrication System

    NASA Technical Reports Server (NTRS)

    Bennett, H. E.

    2003-01-01

    The goals of this ambitious program are (1) to develop systems to make large superpolished optical mirrors, (2) to develop low scatter polishing techniques using centrifugal elutriation, (3) to develop a means of measuring scatter at any point on the mirror, (4) to polish a Hindle sphere to measure the optical figure of a one meter diameter convex mandrel, and (5) to fabricate low scatter, large adaptive optic graphite filled, cyanate ester replica transfer mirrors using these mandrels. Deliverables are a 30 cm diameter superpolished composite AO mirror. We fabricated a 1/3rd meter superpolished zerodur flat mandrel and with the support of our major subcontractor, Composite Mirror Applications Inc (CMA) we have demonstrated a 30 cm lightweight cyanate ester mirror with an rms microroughness between 0.6 and 0.8 nm and 8 faceplate influence function of 5 cm. The influence function was chosen to be comparable to the atmospheric correlation coefficient r(sub 0) which is about 5 cm at sea level. There was no print-thru of the graphite fibers in the cyanate ester surface (the bane of many previous efforts to use cyanate ester mirrors). Our subcontractor has devised a means for developing a 30-50 nm thick layer of graphite free pure ester resin on the surface of the mirrors. This graphite fiber filled material has a thermal expansion coefficient in the 10(exp -8) centimeter per Kelvin range (the same range of expansion coefficient as Zerodur and ULE glasses) and does not take up water and swell, so it is a nearly ideal mirror material in these areas. Unfortunately for these 0.8mm thick faceplates, the number of plies is not enough to result in isometric coverage. Isolated figure irregularities can appear, making it necessary to go to thicker faceplates. The influence function will then only approximate the length of r(sub 0), at higher altitudes or longer wavelengths. The influence function goes as the cube of the thickness, so we are now making a faceplate optimized for

  3. Environmental effects and large space systems

    NASA Technical Reports Server (NTRS)

    Garrett, H. B.

    1981-01-01

    When planning large scale operations in space, environmental impact must be considered in addition to radiation, spacecraft charging, contamination, high power and size. Pollution of the atmosphere and space is caused by rocket effluents and by photoelectrons generated by sunlight falling on satellite surfaces even light pollution may result (the SPS may reflect so much light as to be a nuisance to astronomers). Large (100 Km 2) structures also will absorb the high energy particles that impinge on them. Altogether, these effects may drastically alter the Earth's magnetosphere. It is not clear if these alterations will in any way affect the Earth's surface climate. Large structures will also generate large plasma wakes and waves which may cause interference with communications to the vehicle. A high energy, microwave beam from the SPS will cause ionospheric turbulence, affecting UHF and VHF communications. Although none of these effects may ultimately prove critical, they must be considered in the design of large structures.

  4. Microgrid-Ready Solar PV; NREL (National Renewable Energy Laboratory)

    SciTech Connect

    2015-07-01

    Designing new solar projects to be 'microgrid-ready' enables the U.S. DoD, other federal agencies, and the private sector to plan future microgrid initiatives to utilize solar PV as a generating resource. This fact sheet provides background information with suggested language for several up-front considerations that can be added to a solar project procurement or request for proposal (RFP) that will help ensure that PV systems are built for future microgrid connection.

  5. Pressure-equalizing PV assembly and method

    DOEpatents

    Dinwoodie, Thomas L.

    2004-10-26

    Each PV assembly of an array of PV assemblies comprises a base, a PV module and a support assembly securing the PV module to a position overlying the upper surface of the base. Vents are formed through the base. A pressure equalization path extends from the outer surface of the PV module, past the PV module, to and through at least one of the vents, and to the lower surface of the base to help reduce wind uplift forces on the PV assembly. The PV assemblies may be interengaged, such as by interengaging the bases of adjacent PV assemblies. The base may include a main portion and a cover and the bases of adjacent PV assemblies may be interengaged by securing the covers of adjacent bases together.

  6. PV module mounting method and mounting assembly

    DOEpatents

    Lenox, Carl J.S.; Johnson, Kurt M.

    2013-04-23

    A method for mounting PV modules to a deck includes selecting PV module layout pattern so that adjacent PV module edges are spaced apart. PV mounting and support assemblies are secured to the deck according to the layout pattern using fasteners extending into the deck. The PV modules are placed on the PV mounting and support assemblies. Retaining elements are located over and secured against the upper peripheral edge surfaces of the PV modules so to secure them to the deck with the peripheral edges of the PV modules spaced apart from the deck. In some examples a PV module mounting assembly, for use on a shingled deck, comprises flashing, a base mountable on the flashing, a deck-penetrating fastener engageable with the base and securable to the deck so to secure the flashing and the base to the shingled deck, and PV module mounting hardware securable to the base.

  7. PSCAD Modules Representing PV Generator

    SciTech Connect

    Muljadi, E.; Singh, M.; Gevorgian, V.

    2013-08-01

    Photovoltaic power plants (PVPs) have been growing in size, and the installation time is very short. With the cost of photovoltaic (PV) panels dropping in recent years, it can be predicted that in the next 10 years the contribution of PVPs to the total number of renewable energy power plants will grow significantly. In this project, the National Renewable Energy Laboratory (NREL) developed a dynamic modeling of the modules to be used as building blocks to develop simulation models of single PV arrays, expanded to include Maximum Power Point Tracker (MPPT), expanded to include PV inverter, or expanded to cover an entire PVP. The focus of the investigation and complexity of the simulation determines the components that must be included in the simulation. The development of the PV inverter was covered in detail, including the control diagrams. Both the current-regulated voltage source inverter and the current-regulated current source inverter were developed in PSCAD. Various operations of the PV inverters were simulated under normal and abnormal conditions. Symmetrical and unsymmetrical faults were simulated, presented, and discussed. Both the three-phase analysis and the symmetrical component analysis were included to clarify the understanding of unsymmetrical faults. The dynamic model validation was based on the testing data provided by SCE. Testing was conducted at SCE with the focus on the grid interface behavior of the PV inverter under different faults and disturbances. The dynamic model validation covers both the symmetrical and unsymmetrical faults.

  8. An Expert System Approach to Large Space Systems Control

    DTIC Science & Technology

    1988-10-01

    ISPONSORING 8b. OFFICE SYMBOL 9. PROCUREMENT INSTRUMENT IDENTIFICATION NUMBER ORGANIZATION Of appil ,k) FOSR F49620-87- C --0105 8¢. ADDRESS (CRtY, Stat...oo...0 - An Expert System Approach To Large Space Systems Control Octobe 1988Accession For NTIS R& DTIC TAB C . GartrmII Unannounced E W...4.4.1 Case A: I Newton Harmonic Wave with a Frequency of 0.14 Hz 4-12 4.4.2 Case B: 1 Newton Impulse at x = 2.5 m 4-13 4.4.3 Case C : Traveling Wave with

  9. Radiometric networks and data bases for PV design and performance evaluation

    SciTech Connect

    Stoffel, T.

    1995-09-01

    Access to reliable sources of solar radiation data is an important aspect of photovoltaic (PV) system design and performance evaluation. The purpose of this paper is to provide an overview of non-commercial sources of solar radiation data and related meterological information available nationally and internationally to the PV system designer for applying the information to a PV system. A summary of measurement types, associated instrumentation, and sources of measured data are presented.

  10. Designing PV Incentive Programs to Promote Performance: A Reviewof Current Practice

    SciTech Connect

    Barbose, Galen; Wiser, Ryan; Bolinger, Mark

    2007-06-01

    Increasing levels of financial support for customer-sited photovoltaic (PV) systems, provided through publicly-funded incentive programs, has heightened concerns about the long-term performance of these systems. Given the barriers that customers face to ensuring that their PV systems perform well, and the responsibility that PV incentive programs bear to ensure that public funds are prudently spent, these programs should, and often do, play a critical role in ensuring that PV systems receiving incentives perform well. To provide a point of reference for assessing the current state of the art, and to inform program design efforts going forward, we examine the approaches to encouraging PV system performance used by 32 prominent PV incentive programs in the U.S. We identify eight general strategies or groups of related strategies that these programs have used to address performance issues, and highlight important differences in the implementation of these strategies among programs.

  11. An Analysis of the Effects of Residential Photovoltaic Energy Systems on Home Sales Prices in California

    SciTech Connect

    Hoen, Ben; Cappers, Peter; Wiser, Ryan; Thayer, Mark

    2011-04-19

    An increasing number of homes in the U.S. have sold with photovoltaic (PV) energy systems installed at the time of sale, yet relatively little research exists that estimates the marginal impacts of those PV systems on home sale prices. A clearer understanding of these possible impacts might influence the decisions of homeowners considering the installation of a PV system, homebuyers considering the purchase of a home with PV already installed, and new home builders considering including PV as an optional or standard product on their homes. This research analyzes a large dataset of California homes that sold from 2000 through mid-2009 with PV installed. It finds strong evidence that homes with PV systems sold for a premium over comparable homes without PV systems during this time frame. Estimates for this premium expressed in dollars per watt of installed PV range, on average, from roughly $4 to $5.5/watt across a large number of hedonic and repeat sales model specifications and robustness tests. When expressed as a ratio of the sales price premium of PV to estimated annual energy cost savings associated with PV, an average ratio of 14:1 to 19:1 can be calculated; these results are consistent with those of the more-extensive existing literature on the impact of energy efficiency on sales prices. When the data are split among new and existing homes, however, PV system premiums are markedly affected. New homes with PV show premiums of $2.3-2.6/watt, while existing homes with PV show premiums of more than $6/watt. Reasons for this discrepancy are suggested, yet further research is warranted. A number of other areas where future research would be useful are also highlighted.

  12. Comparative analysis of solar photovoltaic monitoring systems

    NASA Astrophysics Data System (ADS)

    Madeti, Siva Ramakrishna; Singh, S. N.

    2017-07-01

    This paper is focused on comparative analysis of photovoltaic (PV) monitoring system for observing the performance and stability of the system. The cost and complexity of existing PV monitoring systems restricted their use to large scale PV plants. Over the past decade, different aspects of the PV monitoring systems were reported in the wide range of literature. In this paper, a comparative analysis of various PV monitoring systems is presented for the first time. It is based on analyzing six main characteristics of PV monitoring system, such as data transfer mechanism, controller, monitoring parameters, sampling interval, program development software and monitoring methods. The comparison of methodologies and the description of implementation process are discussed in this context. The key findings of this study will contribute to the development of a new PV monitoring system. The acquaintance of all these aspects is crucial for the development of effective, low cost, and viable PV monitoring systems for the small and medium scale PV plants without compromising on the desired performance.

  13. Status of DOE and AID stand-alone photovoltaic system field tests

    NASA Technical Reports Server (NTRS)

    Bifano, W. J.; Delombard, R.; Ratajczak, A. F.; Scudder, L. R.

    1984-01-01

    The NASA Lewis Research Center (LeRC) is managing stand-alone photovoltaic (PV) system projects sponsored by the U.S. Department of Energy (DOE) and the U.S. Agency for International Development (AID). The DOE project includes village PV power demonstration projects in Gabon (four sites) and the Marshall Islands, and PV-powered vaccine refrigerator systems in six countries. The AID project includes a large village power system, a farmhouse system and two water pumping-irrigation systems in Tunisia, a water pumping/grain grinding system in Upper Volta, five medical clinic systems in four countries, PV-powered vaccine refrigerator systems in 18 countries and a PV-powered remote earth station in Indonesia. This paper reviews these PV projects and summarizes significant findings to date.

  14. Status of DOE and AID stand-alone photovoltaic system field tests

    NASA Astrophysics Data System (ADS)

    Bifano, W. J.; Delombard, R.; Ratajczak, A. F.; Scudder, L. R.

    The NASA Lewis Research Center (LeRC) is managing stand-alone photovoltaic (PV) system projects sponsored by the U.S. Department of Energy (DOE) and the U.S. Agency for International Development (AID). The DOE project includes village PV power demonstration projects in Gabon (four sites) and the Marshall Islands, and PV-powered vaccine refrigerator systems in six countries. The AID project includes a large village power system, a farmhouse system and two water pumping-irrigation systems in Tunisia, a water pumping/grain grinding system in Upper Volta, five medical clinic systems in four countries, PV-powered vaccine refrigerator systems in 18 countries and a PV-powered remote earth station in Indonesia. This paper reviews these PV projects and summarizes significant findings to date.

  15. Status of DOE and AID stand-alone photovoltaic system field tests

    NASA Technical Reports Server (NTRS)

    Bifano, W. J.; Delombard, R.; Ratajczak, A. F.; Scudder, L. R.

    1984-01-01

    The NASA Lewis Research Center (LeRC) is managing stand-alone photovoltaic (PV) system projects sponsored by the U.S. Department of Energy (DOE) and the U.S. Agency for International Development (AID). The DOE project includes village PV power demonstration projects in Gabon (four sites) and the Marshall Islands, and PV-powered vaccine refrigerator systems in six countries. The AID project includes a large village power system, a farmhouse system and two water pumping-irrigation systems in Tunisia, a water pumping/grain grinding system in Upper Volta, five medical clinic systems in four countries, PV-powered vaccine refrigerator systems in 18 countries and a PV-powered remote earth station in Indonesia. This paper reviews these PV projects and summarizes significant findings to date.

  16. A bibliographical surveys of large-scale systems

    NASA Technical Reports Server (NTRS)

    Corliss, W. R.

    1970-01-01

    A limited, partly annotated bibliography was prepared on the subject of large-scale system control. Approximately 400 references are divided into thirteen application areas, such as large societal systems and large communication systems. A first-author index is provided.

  17. Evaluating Inuence of Power Output Fluctuation of Photovoltaic Power Generation Systems on LFC based on Multiple Observation of Insolation

    NASA Astrophysics Data System (ADS)

    Yanagawa, Shigeyuki; Kato, Takeyoshi; Tabata, Akimori; Suzuoki, Yasuo

    A large-scale installation of a photovoltaic power generation system (PV system) may cause some diculties in the operation of electric power systems. Taking into account a smoothing effect of power outputs of PV systems by dispersed installation, this paper discusses the LFC (Load Frequency Control) capacity for power output fluctuation of PV systems based on the insolation data simultaneously observed at 5 points around Nagoya, Japan. The main results are (1) the frequency deviation might not exceed the tolerance (0.05Hz)when the installed PV system is 2% of system capacity, which is Japan’s target value toward 2010, (2) when the larger capacity of PV system is installed, the frequency deviation would be larger than 0.05Hz, and the capacity of LFC generator must be increased, (3) the frequency deviation due to the installation of PV system might be larger in holiday with smaller electricity demand than in weekday.

  18. Identification of a locus in arabidopsis controlling both the expression of rhizobacteria-mediated induced systemic resistance (ISR) and basal resistance against Pseudomonas syringae pv. tomato.

    PubMed

    Ton, J; Pieterse, C M; Van Loon, L C

    1999-10-01

    Selected nonpathogenic rhizobacteria with biological disease control activity are able to elicit an induced systemic resistance (ISR) response that is phenotypically similar to pathogen-induced systemic acquired resistance (SAR). Ten ecotypes of Arabidopsis thaliana were screened for their potential to express rhizobacteria-mediated ISR and pathogen-induced SAR against the leaf pathogen Pseudomonas syringae pv. tomato DC3000 (Pst). All ecotypes expressed SAR. However, of the 10 ecotypes tested, ecotypes RLD and Wassilewskija (Ws) did not develop ISR after treatment of the roots with nonpathogenic Pseudomonas fluorescens WCS417r bacteria. This nonresponsive phenotype was associated with relatively high susceptibility to Pst infection. The F1 progeny of crosses between the non-responsive ecotypes RLD and Ws on the one hand, and the responsive ecotypes Columbia (Col) and Landsberg erecta (Ler) on the other hand, were fully capable of expressing ISR and exhibited a relatively high level of basal resistance, similar to that of their WCS417r-responsive parent. This indicates that the potential to express ISR and the relatively high level of basal resistance against Pst are both inherited as dominant traits. Analysis of the F2 and F3 progeny of a Col x RLD cross revealed that inducibility of ISR and relatively high basal resistance against Pst cosegregate in a 3:1 fashion, suggesting that both resistance mechanisms are monogenically determined and genetically linked. Neither the responsiveness to WCS417r nor the relatively high level of basal resistance against Pst were complemented in the F1 progeny of crosses between RLD and Ws, indicating that RLD and Ws are both affected in the same locus, necessary for the expression of ISR and basal resistance against Pst. The corresponding locus, designated ISR1, was mapped between markers B4 and GL1 on chromosome 3. The observed association between ISR and basal resistance against Pst suggests that rhizobacteria-mediated ISR

  19. Review of PV Inverter Technology Cost and Performance Projections

    SciTech Connect

    Navigant Consulting Inc.

    2006-01-01

    The National Renewable Energy Laboratory (NREL) has a major responsibility in the implementation of the U.S. Department of Energy's (DOE's) Solar Energy Technologies Program. Sandia National Laboratories (SNL) has a major role in supporting inverter development, characterization, standards, certifications, and verifications. The Solar Energy Technologies Program recently published a Multiyear Technical Plan, which establishes a goal of reducing the Levelized Energy Cost (LEC) for photovoltaic (PV) systems to $0.06/kWh by 2020. The Multiyear Technical Plan estimates that, in order to meet the PV system goal, PV inverter prices will need to decline to $0.25-0.30 Wp by 2020. DOE determined the need to conduct a rigorous review of the PV Program's technical and economic targets, including the target set for PV inverters. NREL requested that Navigant Consulting Inc.(NCI) conduct a review of historical and projected cost and performance improvements for PV inverters, including identification of critical barriers identified and the approaches government might use to address them.

  20. How Can We Make PV Modules Safer?: Preprint

    SciTech Connect

    Wohlgemuth, J. H.; Kurtz, S. R.

    2012-06-01

    Safety is a prime concern for the photovoltaics (PV) industry. As a technology deployed on residential and commercial buildings, it is critical that PV not cause damage to the buildings nor harm the occupants. Many of the PV systems on buildings are of sufficiently high voltage (300 to 600 Volts dc) that they may present potential hazards. These PV systems must be safe in terms of mechanical damage (nothing falls on someone), shock hazard (no risk of electrical shock when touching an exposed circuit element), and fire (the modules neither cause nor promote a fire). The present safety standards (IEC 61730 and UL 1703) do a good job of providing for design rules and test requirements for mechanical, shock, and spread of flame dangers. However, neither standard addresses the issue of electrical arcing within a module that can cause a fire. To make PV modules, they must be designed, built, and installed with an emphasis on minimizing the potential for open circuits and ground faults. This paper provides recommendations on redundant connection designs, robust mounting methods, and changes to the safety standards to yield safer PV modules.

  1. Comparative Analysis of PvPAP Gene Family and Their Functions in Response to Phosphorus Deficiency in Common Bean

    PubMed Central

    Liang, Cuiyue; Sun, Lili; Yao, Zhufang; Liao, Hong; Tian, Jiang

    2012-01-01

    Background Purple acid phosphatases (PAPs) play a vital role in adaptive strategies of plants to phosphorus (P) deficiency. However, their functions in relation to P efficiency are fragmentary in common bean. Principal Findings Five PvPAPs were isolated and sequenced in common bean. Phylogenetic analysis showed that PvPAPs could be classified into two groups, including a small group with low molecular mass, and a large group with high molecular mass. Among them, PvPAP3, PvPAP4 and PvPAP5 belong to the small group, while the other two belong to the large group. Transient expression of 35S:PvPAPs-GFP on onion epidermal cells verified the variations of subcellular localization among PvPAPs, suggesting functional diversities of PvPAPs in common bean. Quantitative PCR results showed that most PvPAPs were up-regulated by phosphate (Pi) starvation. Among them, the expression of the small group PvPAPs responded more to Pi starvation, especially in the roots of G19833, the P-efficient genotype. However, only overexpressing PvPAP1 and PvPAP3 could result in significantly increased utilization of extracellular dNTPs in the transgenic bean hairy roots. Furthermore, overexpressing PvPAP3 in Arabidopsis enhanced both plant growth and total P content when dNTPs were supplied as the sole external P source. Conclusions The results suggest that PvPAPs in bean varied in protein structure, response to P deficiency and subcellular localization. Among them, both PvPAP1 and PvPAP3 might function as utilization of extracellular dNTPs. PMID:22662274

  2. 75 FR 21455 - Large Trader Reporting System

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-23

    ... substantial amount of trading activity, as measured by volume or market value, in the U.S. securities markets.... All comments received will be posted without change; the Commission does not edit personal identifying... transactions involving a substantial volume or large fair market value, as well as to assist the...

  3. Assessing Stakeholder Input in a Large System.

    ERIC Educational Resources Information Center

    Kuzmyn, Zenon J.; Collet, Leverne S.

    The intent of this paper is to illustrate the use of stakeholder information in evaluating a school program. The material presented is part of a comprehensive formative evaluation of a crisis intervention program operated by a suburban school district situated near a large industrial city in the Midwest. The crisis intervention program provided…

  4. PV solar electricity: status and future

    NASA Astrophysics Data System (ADS)

    Hoffmann, Winfried

    2006-04-01

    Within the four main market segments of PV solar electricity there are already three areas competitive today. These are off-grid industrial and rural as well as consumer applications. The overall growth within the past 8 years was almost 40 % p.a. with a "normal" growth of about 18 % p.a. for the first three market segments whereas the grid connected market increased with an astonishing 63 % p.a. The different growth rates catapulted the contribution of grid connected systems in relation to the total market from about one quarter 6 years ago towards more than three quarters today. The reason for this development is basically due to industry-politically induced market support programs in the aforementioned countries. It is quite important to outline under which boundary conditions grid connected systems will be competitive without support programs like the feed in tariff system in Germany, Spain and some more to come in Europe as well as investment subsidies in Japan, US and some other countries. It will be shown that in a more and more liberalized utility market worldwide electricity produced by PV solar electricity systems will be able to compete with their generating cost against peak power prices from utilities. The point of time for this competitiveness is mainly determined by the following facts: 1. Price decrease for PV solar electricity systems leading to an equivalent decrease in the generated cost for PV produced kWh. 2. Development of a truly liberalized electricity market. 3. Degree of irradiation between times of peak power demand and delivery of PV electricity. The first topic is discussed using price experience curves. Some explanations will be given to correlate the qualitative number of 20 % price decrease for doubling cumulative worldwide sales derived from the historic price experience curve with a more quantitative analysis based on our EPIA-Roadmap (productivity increase and ongoing improvements for existing technologies as well as development

  5. Component Cost Analysis of Large Scale Systems

    NASA Technical Reports Server (NTRS)

    Skelton, R. E.; Yousuff, A.

    1982-01-01

    The ideas of cost decomposition is summarized to aid in the determination of the relative cost (or 'price') of each component of a linear dynamic system using quadratic performance criteria. In addition to the insights into system behavior that are afforded by such a component cost analysis CCA, these CCA ideas naturally lead to a theory for cost-equivalent realizations.

  6. Large-scale systems: Complexity, stability, reliability

    NASA Technical Reports Server (NTRS)

    Siljak, D. D.

    1975-01-01

    After showing that a complex dynamic system with a competitive structure has highly reliable stability, a class of noncompetitive dynamic systems for which competitive models can be constructed is defined. It is shown that such a construction is possible in the context of the hierarchic stability analysis. The scheme is based on the comparison principle and vector Liapunov functions.

  7. Millimeter Wave Applications of Large Aperture Systems

    DTIC Science & Technology

    1980-02-01

    unit step impulse ................. 89 5-8 Truss/tower model. Joints identification numbers ............... 91 5-9 z-displacement (m) histories for the...tip joint 801 displacements for 1 cycle steady-state response to harmonic excitation (15 N at 10 Hz) ................ 101 6-1 Elliptic torus 30 x 60 m...freedom (DOF) -o a reasonable level, the large platform was modelled with axial members whereby only three DOF’s are present nat each joint . Although

  8. Large Space Systems Technology, 1979. [antenna and space platform systems conference

    NASA Technical Reports Server (NTRS)

    Ward, J. C., Jr. (Compiler)

    1980-01-01

    Items of technology and developmental efforts in support of the large space systems technology programs are described. The major areas of interest are large antennas systems, large space platform systems, and activities that support both antennas and platform systems.

  9. Thermal Insulation System for Large Flame Buckets

    NASA Technical Reports Server (NTRS)

    Callens, E. Eugene, Jr.; Gamblin, Tonya Pleshette

    1996-01-01

    The objective of this study is to investigate the use of thermal protection coatings, single tiles, and layered insulation systems to protect the walls of the flame buckets used in the testing of the Space Shuttle Main Engine, while reducing the cost and maintenance of the system. The physical behavior is modeled by a plane wall boundary value problem with a convective frontface condition and a backface condition designed to provide higher heat rates through the material.

  10. Large Caliber Gun Tube Materials Systems Design

    DTIC Science & Technology

    2001-04-26

    gun tube environment and current gun tube materials, properties , dimensions, and fabrication methods will be reviewed, as well as the erosion test...for a tank gun is shown in Figure 1. Any materials system can be examined in terms of PROCESSING! MANUFACTURING, STRUCTURE/COMPOSITION, PROPERTIES ...part of gun materials systems design. The list of required and desired properties is long, and a material that satisfies the list completely does not

  11. Statistical overview of findings by IR-inspections of PV-plants

    NASA Astrophysics Data System (ADS)

    Buerhop, Claudia; Pickel, Tobias; Scheuerpflug, Hans; Camus, Christian; Hauch, Jens; Brabec, Christoph J.

    2016-09-01

    First statistical evaluation of IR-inspections of PV-plants reveals that 86% of the installed PV-plants show IR-abnormalities. More than 120 PV-plants with more than 160,000 PV-modules were inspected and evaluated statistically. Main IR-abnormalities or failures in modules and string installations are analyzed, respectively. The average failure rate for PV-modules is about 8% and for module strings approximately 4%. The differentiation between the installation locations reveals that small residential installation show relatively more defective modules than large field installations. - Therefore, IR-imaging is a valuable method to give fast and reliable information about the actual quality and failure rate in inspected PV-installations.

  12. Simulation of large systems with neural networks

    SciTech Connect

    Paez, T.L.

    1994-09-01

    Artificial neural networks (ANNs) have been shown capable of simulating the behavior of complex, nonlinear, systems, including structural systems. Under certain circumstances, it is desirable to simulate structures that are analyzed with the finite element method. For example, when we perform a probabilistic analysis with the Monte Carlo method, we usually perform numerous (hundreds or thousands of) repetitions of a response simulation with different input and system parameters to estimate the chance of specific response behaviors. In such applications, efficiency in computation of response is critical, and response simulation with ANNs can be valuable. However, finite element analyses of complex systems involve the use of models with tens or hundreds of thousands of degrees of freedom, and ANNs are practically limited to simulations that involve far fewer variables. This paper develops a technique for reducing the amount of information required to characterize the response of a general structure. We show how the reduced information can be used to train a recurrent ANN. Then the trained ANN can be used to simulate the reduced behavior of the original system, and the reduction transformation can be inverted to provide a simulation of the original system. A numerical example is presented.

  13. Laser measuring system for large machine tools

    NASA Astrophysics Data System (ADS)

    Wessel, L. E.; Brazys, D.

    1982-08-01

    With development of the Laser Interferometer, it was envisioned that older existing machine tools could be up-graded by retrofitting them with laser Interferometer Measuring Systems. The Laser Interferometer provides the machine tool industry with a high accuracy length standard. The accuracy of the Interferometer is determined by the laser wave length which is known within 0.5 parts per million. This degree of accuracy is more than adequate for most machine tool measuring, calibration and inspection requirements. In conclusion, the Laser Measuring System presently available is not recommended for general implementation at this time. Results of this work indicate that the equipment and installation cost are very high and pay back would be very slow. Also, the reliability of the electronic components is in need of improvement. The system requires frequent realignment and maintenance due to it's lack of toleration to "Shop Floor' conditions.

  14. The future of large optical system verification

    NASA Astrophysics Data System (ADS)

    Matthews, Gary

    2005-08-01

    As optical systems grow in size, there becomes a point in which traditional system verification prior to launch will become impossible. This implies that observatory ground testing will not be completed. Our history does not support this premise and therefore results in an unacceptable programmatic risk. But, if the dream of building 20-30 meter systems is ever to become true, these realities must be accepted. To make this possible, new and better analytical tools and processes must be developed and certified on programs that can be tested on the ground. This change in paradigm does not eliminate critical testing; it just does it at different assembly levels and most likely adds alignment flexibility to correct optical errors after launch. This paper provides ideas on how the hardware, analysis tools, and testing may evolve to support these ambitious future programs.

  15. Tools for Enhanced Grid Operation and Optimized PV Penetration Utilizing Highly Distributed Sensor Data.

    SciTech Connect

    Reno, Matthew J.; Peppanen, Jouni; Seuss, John; Lave, Matthew Samuel; Broderick, Robert Joseph; Grijalva, Santiago

    2015-11-01

    Increasing number s of PV on distribution systems are creating more grid impacts , but it also provides more opportunities for measurement, sensing, and control of the grid in a distributed fashion. This report demonstrates three software tools for characterizing and controlling distribution feeders by utilizing large numbers of highly distributed current, voltage , and irradiance sensors. Instructions and a user manual is presented for each tool. First, the tool for distribution system secondary circuit parameter estimation is presented. This tool allows studying distribution system parameter estimation accuracy with user-selected active power, reactive power, and voltage measurements and measurement error levels. Second, the tool for multi-objective inverter control is shown. Various PV inverter control strategies can be selected to objectively compare their impact on the feeder. Third, the tool for energy storage for PV ramp rate smoothing is presented. The tool allows the user to select different storage characteristics (power and energy ratings) and control types (local vs. centralized) to study the tradeoffs between state-of-charge (SOC) management and the amount of ramp rate smoothing.

  16. Very Large Scale Distributed Information Processing Systems

    DTIC Science & Technology

    1991-09-27

    34Reliable Distributed Database Management", Proc. of the IEEE, May 1987, pp. 601-620. [GOTT881 Gottlob , Georg andRoberto Zicari, "Closed World Databases... Gottlob , and Gio Wiederhold, "Interfacing Relational Databases and Prolog Efficiently," in Proceedings 2nd Expert Database Systems Conference, pp. 141

  17. Estimation of PV energy production based on satellite data

    NASA Astrophysics Data System (ADS)

    Mazurek, G.

    2015-09-01

    Photovoltaic (PV) technology is an attractive source of power for systems without connection to power grid. Because of seasonal variations of solar radiation, design of such a power system requires careful analysis in order to provide required reliability. In this paper we present results of three-year measurements of experimental PV system located in Poland and based on polycrystalline silicon module. Irradiation values calculated from results of ground measurements have been compared with data from solar radiation databases employ calculations from of satellite observations. Good convergence level of both data sources has been shown, especially during summer. When satellite data from the same time period is available, yearly and monthly production of PV energy can be calculated with 2% and 5% accuracy, respectively. However, monthly production during winter seems to be overestimated, especially in January. Results of this work may be helpful in forecasting performance of similar PV systems in Central Europe and allow to make more precise forecasts of PV system performance than based only on tables with long time averaged values.

  18. Passive stabilization for large space systems

    NASA Technical Reports Server (NTRS)

    Sesak, J. R.; Gronet, M. J.; Marinos, G. M.

    1987-01-01

    The optimal tuning of multiple tuned-mass dampers for the transient vibration damping of large space structures is investigated. A multidisciplinary approach is used. Structural dynamic techniques are applied to gain physical insight into absorber/structure interaction and to optimize specific cases. Modern control theory and parameter optimization techniques are applied to the general optimization problem. A design procedure for multi-absorber multi-DOF vibration damping problems is presented. Classical dynamic models are extended to investigate the effects of absorber placement, existing structural damping, and absorber cross-coupling on the optimal design synthesis. The control design process for the general optimization problem is formulated as a linear output feedback control problem via the development of a feedback control canonical form. The techniques are applied to sample micro-g and pointing problems on the NASA dual keel space station.

  19. Geographic smoothing of solar PV: Results from Gujarat

    DOE PAGES

    Klima, Kelly; Apt, Jay

    2015-09-24

    We examine the potential for geographic smoothing of solar photovoltaic (PV) electricity generation using 13 months of observed power production from utility-scale plants in Gujarat, India. To our knowledge, this is the first published analysis of geographic smoothing of solar PV using actual generation data at high time resolution from utility-scale solar PV plants. We use geographic correlation and Fourier transform estimates of the power spectral density (PSD) to characterize the observed variability of operating solar PV plants as a function of time scale. Most plants show a spectrum that is linear in the log–log domain at high frequencies f,more » ranging from f-1.23 to f-1.56 (slopes of -1.23 and -1.56), thus exhibiting more relative variability at high frequencies than exhibited by wind plants. PSDs for large PV plants have a steeper slope than those for small plants, hence more smoothing at short time scales. Interconnecting 20 Gujarat plants yields a f-1.66 spectrum, reducing fluctuations at frequencies corresponding to 6 h and 1 h by 23% and 45%, respectively. Half of this smoothing can be obtained through connecting 4-5 plants; reaching marginal improvement of 1% per added plant occurs at 12-14 plants. The largest plant (322 MW) showed an f-1.76 spectrum. Furthermore, this suggests that in Gujarat the potential for smoothing is limited to that obtained by one large plant.« less

  20. Geographic smoothing of solar PV: results from Gujarat

    NASA Astrophysics Data System (ADS)

    Klima, Kelly; Apt, Jay

    2015-10-01

    We examine the potential for geographic smoothing of solar photovoltaic (PV) electricity generation using 13 months of observed power production from utility-scale plants in Gujarat, India. To our knowledge, this is the first published analysis of geographic smoothing of solar PV using actual generation data at high time resolution from utility-scale solar PV plants. We use geographic correlation and Fourier transform estimates of the power spectral density (PSD) to characterize the observed variability of operating solar PV plants as a function of time scale. Most plants show a spectrum that is linear in the log-log domain at high frequencies f, ranging from {f}-1.23 to {f}-1.56 (slopes of -1.23 and -1.56), thus exhibiting more relative variability at high frequencies than exhibited by wind plants. PSDs for large PV plants have a steeper slope than those for small plants, hence more smoothing at short time scales. Interconnecting 20 Gujarat plants yields a {f}-1.66 spectrum, reducing fluctuations at frequencies corresponding to 6 h and 1 h by 23% and 45%, respectively. Half of this smoothing can be obtained through connecting 4-5 plants; reaching marginal improvement of 1% per added plant occurs at 12-14 plants. The largest plant (322 MW) showed an {f}-1.76 spectrum. This suggests that in Gujarat the potential for smoothing is limited to that obtained by one large plant.

  1. Systems identification technology development for large space systems

    NASA Technical Reports Server (NTRS)

    Armstrong, E. S.

    1982-01-01

    A methodology for synthesizinng systems identification, both parameter and state, estimation and related control schemes for flexible aerospace structures is developed with emphasis on the Maypole hoop column antenna as a real world application. Modeling studies of the Maypole cable hoop membrane type antenna are conducted using a transfer matrix numerical analysis approach. This methodology was chosen as particularly well suited for handling a large number of antenna configurations of a generic type. A dedicated transfer matrix analysis, both by virtue of its specialization and the inherently easy compartmentalization of the formulation and numerical procedures, is significantly more efficient not only in computer time required but, more importantly, in the time needed to review and interpret the results.

  2. Large artery inflammation in systemic lupus erythematosus.

    PubMed

    Sokalski, D G; Copsey Spring, T R; Roberts, W N

    2013-08-01

    A 23-year-old African-American woman with a history of recurrent pneumonias presented to the hospital with 2 weeks of shortness of breath, chest pain, fevers, and lightheadedness. The histologic diagnosis proved to be lupus aortitis. Optimal Framingham risk factor management by itself may not be a completely successful approach in diminishing the extra risk of atherosclerosis conferred by systemic lupus erythematosus (SLE). Therefore it remains possible that important modifiable cardiovascular risk factors may include low-grade SLE disease activity in medium-sized vessels. The implication of the idea that subclinical vessel inflammation is widespread in patients with lupus-and that this inflammation confers a significant part of the patients' risk of accelerated atherosclerosis-might be a lowering of the threshold for aggressive disease-modifying treatment of lupus, essentially a "treat-to-target" approach to systemic lupus.

  3. GacS-dependent production of 2R, 3R-butanediol by Pseudomonas chlororaphis O6 is a major determinant for eliciting systemic resistance against Erwinia carotovora but not against Pseudomonas syringae pv. tabaci in tobacco.

    PubMed

    Han, Song Hee; Lee, Seung Je; Moon, Jae Hak; Park, Keun Hyung; Yang, Kwang Yeol; Cho, Balk Ho; Kim, Kil Yong; Kim, Yong Whan; Lee, Myung Chul; Anderson, Anne J; Kim, Young Cheol

    2006-08-01

    Root colonization by a plant-beneficial rhizobacterium, Pseudomonas chlororaphis O6, induces disease resistance in tobacco against leaf pathogens Erwinia carotovora subsp. carotovora SCC1, causing soft-rot, and Pseudomonas syringae pv. tabaci, causing wildfire. In order to identify the bacterial determinants involved in induced systemic resistance against plant diseases, extracellular components produced by the bacterium were fractionated and purified. Factors in the culture filtrate inducing systemic resistance were retained in the aqueous fraction rather than being partitioned into ethyl acetate. Fractionation on high-performance liquid chromatography followed by nuclear magnetic resonance mass spectrometry analysis identified the active compound as 2R, 3R-butanediol. 2R, 3R butanediol induced systemic resistance in tobacco to E. carotovora subsp. carotovora SCC1, but not to P. syringae pv. tabaci. Treatment of tobacco with the volatile 2R, 3R-butanediol enhanced aerial growth, a phenomenon also seen in plants colonized by P. chlororaphis O6. The isomeric form of the butanediol was important because 2S, 3S-butandiol did not affect the plant. The global sensor kinase, GacS, of P. chlororaphis O6 was a key regulator for induced systemic resistance against E. carotovora through regulation of 2R, 3R-butanediol production. This is the first report of the production of these assumed fermentation products by a pseudomonad and the role of the sensor kinase GacS in production of 2R, 3R-butanediol.

  4. Large space systems in global change mitigation

    NASA Technical Reports Server (NTRS)

    Jenkins, Lyle M.

    1990-01-01

    The monitoring from space of such processes as the greenhouse effect and depletion of the ozone layer is discussed, as well as possibilities for active intervention in them, using space systems. Possibilities include the use of the Solar Power Satellite to reduce dependence on the burning of fossil fuels, dispersal of materials to neutralize chemicals responsible for ozone depletion, and measures to reduce the impact of local disasters, both natural and man-made.

  5. Results from Undergraduate PV Projects at Seven Historically Black Colleges and Universities

    SciTech Connect

    McConnell, R. D.

    1999-03-03

    In 1995, the NREL/Department of Energy (DOE) National Photovoltaics Program funded seven Historically Black Colleges and Universities (HBCUs) in its HBCU Photovoltaic Research Associates Program for a period of three years. The program's purpose is to advance HBCU undergraduate knowledge of photovoltaics, primarily as a result of research investigations performed, and to encourage students to pursue careers in photovoltaics. This paper presents results from PV projects ranging from fundamental materials research on PV materials to field projects of PV systems.

  6. Large Space Systems/Low-Thrust Propulsion Technology

    NASA Technical Reports Server (NTRS)

    1980-01-01

    The potentially critical interactions that occur between propulsion, structures and materials, and controls for large spacecraft are considered, the technology impacts within these fields are defined and the net effect on large systems and the resulting missions is determined. Topical areas are systems/mission analysis, LSS static and dynamic characterization, and propulsion systems characterization.

  7. Performance modeling for large database systems

    NASA Astrophysics Data System (ADS)

    Schaar, Stephen; Hum, Frank; Romano, Joe

    1997-02-01

    One of the unique approaches Science Applications International Corporation took to meet performance requirements was to start the modeling effort during the proposal phase of the Interstate Identification Index/Federal Bureau of Investigations (III/FBI) project. The III/FBI Performance Model uses analytical modeling techniques to represent the III/FBI system. Inputs to the model include workloads for each transaction type, record size for each record type, number of records for each file, hardware envelope characteristics, engineering margins and estimates for software instructions, memory, and I/O for each transaction type. The model uses queuing theory to calculate the average transaction queue length. The model calculates a response time and the resources needed for each transaction type. Outputs of the model include the total resources needed for the system, a hardware configuration, and projected inherent and operational availability. The III/FBI Performance Model is used to evaluate what-if scenarios and allows a rapid response to engineering change proposals and technical enhancements.

  8. NREL/SCE High-Penetration PV Integration Project: Report on Field Demonstration of Advanced Inverter Functionality in Fontana, CA

    SciTech Connect

    Mather, B.

    2014-08-01

    The National Renewable Energy Laboratory/Southern California Edison High-Penetration PV Integration Project is (1) researching the distribution system level impacts of high-penetration photovoltaic (PV) integration, (2) determining mitigation methods to reduce or eliminate those impacts, and (3) seeking to demonstrate these mitigation methods on actual high-penetration PV distribution circuits. This report describes a field demonstration completed during the fall of 2013 on the Fontana, California, study circuit, which includes a total of 4.5 MW of interconnected utility-scale rooftop PV systems. The demonstration included operating a 2-MW PV system at an off-unity power factor that had been determined during previously completed distribution system modeling and PV impact assessment analyses. Data on the distribution circuit and PV system operations were collected during the 2-week demonstration period. This demonstration reinforces the findings of previous laboratory testing that showed that utility-scale PV inverters are capable of operating at off-unity power factor to mitigate PV impacts; however, because of difficulties setting and retaining PV inverter power factor set points during the field demonstration, it was not possible to demonstrate the effectiveness of off-unity power factor operation to mitigate the voltage impacts of high-penetration PV integration. Lessons learned from this field demonstration are presented to inform future field demonstration efforts.

  9. Fructose-bisphophate aldolase exhibits functional roles between carbon metabolism and the hrp system in rice pathogen Xanthomonas oryzae pv. oryzicola.

    PubMed

    Guo, Wei; Zou, Li-fang; Li, Yu-rong; Cui, Yi-ping; Ji, Zhi-yuan; Cai, Lu-lu; Zou, Hua-song; Hutchins, William C; Yang, Ching-hong; Chen, Gong-you

    2012-01-01

    Fructose-bisphophate aldolase (FbaB), is an enzyme in glycolysis and gluconeogenesis in living organisms. The mutagenesis in a unique fbaB gene of Xanthomonas oryzae pv. oryzicola, the causal agent of rice bacterial leaf streak, led the pathogen not only unable to use pyruvate and malate for growth and delayed its growth when fructose was used as the sole carbon source, but also reduced extracellular polysaccharide (EPS) production and impaired bacterial virulence and growth in rice. Intriguingly, the fbaB promoter contains an imperfect PIP-box (plant-inducible promoter) (TTCGT-N(9)-TTCGT). The expression of fbaB was negatively regulated by a key hrp regulatory HrpG and HrpX cascade. Base substitution in the PIP-box altered the regulation of fbaB with the cascade. Furthermore, the expression of fbaB in X. oryzae pv. oryzicola RS105 strain was inducible in planta rather than in a nutrient-rich medium. Except other hrp-hrc-hpa genes, the expression of hrpG and hrpX was repressed and the transcripts of hrcC, hrpE and hpa3 were enhanced when fbaB was deleted. The mutation in hrcC, hrpE or hpa3 reduced the ability of the pathogen to acquire pyruvate and malate. In addition, bacterial virulence and growth in planta and EPS production in RΔfbaB mutant were completely restored to the wild-type level by the presence of fbaB in trans. This is the first report to demonstrate that carbohydrates, assimilated by X. oryzae pv. oryzicola, play critical roles in coordinating hrp gene expression through a yet unknown regulator.

  10. Operation of Grid-tied 5 kWDC solar array to develop Laboratory Experiments for Solar PV Energy System courses

    SciTech Connect

    Ramos, Jaime

    2012-12-14

    To unlock the potential of micro grids we plan to build, commission and operate a 5 kWDC PV array and integrate it to the UTPA Engineering building low voltage network, as a micro grid; and promote community awareness. Assisted by a solar radiation tracker providing on-line information of its measurements and performing analysis for the use by the scientific and engineering community, we will write, perform and operate a set of Laboratory experiments and computer simulations supporting Electrical Engineering (graduate and undergraduate) courses on Renewable Energy, as well as Senior Design projects.

  11. Performance regression manager for large scale systems

    DOEpatents

    Faraj, Daniel A.

    2017-08-01

    System and computer program product to perform an operation comprising generating, based on a first output generated by a first execution instance of a command, a first output file specifying a value of at least one performance metric, wherein the first output file is formatted according to a predefined format, comparing the value of the at least one performance metric in the first output file to a value of the performance metric in a second output file, the second output file having been generated based on a second output generated by a second execution instance of the command, and outputting for display an indication of a result of the comparison of the value of the at least one performance metric of the first output file to the value of the at least one performance metric of the second output file.

  12. Selecting Solar: Insights into Residential Photovoltaic (PV) Quote Variation

    SciTech Connect

    Davidson, Carolyn; Margolis, Robert

    2015-10-01

    Before investing in a system, a prospective PV customer must not only have initial concept 'buy in,' but also be able to evaluate the tradeoffs associated with different system parameters. Prospective customers might need to evaluate disparate costs for each system attribute by comparing multiple bids. The difficulty of making such an evaluation with limited information can create a cognitive barrier to proceeding with the investment. This analysis leverages recently available data from EnergySage, an online solar marketplace, to offer the first data-driven characterization of quote variation faced by prospective PV customers, lending early insight into the decisions customers face once they have initial buy-in.

  13. Draft genome sequences of three Xanthomonas translucens pathovar reference strains (pv. arrhenatheri, pv. poae and pv. phlei) with different specificities for forage grasses.

    PubMed

    Hersemann, Lena; Wibberg, Daniel; Widmer, Franco; Vorhölter, Frank-Jörg; Kölliker, Roland

    2016-01-01

    As causal agents of bacterial wilt in pastures and meadows, bacteria of the species Xanthomonas translucens are a serious issue in forage grass production. So far, only little is known about host-pathogen interactions at the molecular level and the lack of comprehensive genome data impeded targeted breeding strategies towards resistant forage grass cultivars. Here we announce the draft genome sequences of three grass-pathogenic Xanthomonas translucens pathotype strains, i.e. pv. arrhenatheri LMG 727, pv. poae LMG 728 and pv. phlei LMG 730 isolated from Arrhenatherum elatius (L.) P. Beauv. ex J. Presl & C. Presl (Switzerland), Poa trivialis L. (Switzerland) and Phleum pratense L. (Norway), respectively. The genomes of all three strains revealed a non-canonical type III secretion system and a set of 22 type III effectors as common virulence-related traits. Distinct inter-pathovar differences were observed for the lipopolysaccharide biosynthesis gene cluster and the presence of nonribosomal peptide synthetases.

  14. Use of cryopumps on large space simulation systems

    NASA Technical Reports Server (NTRS)

    Mccrary, L. E.

    1980-01-01

    The need for clean, oil free space simulation systems has demanded the development of large, clean pumping systems. The assurance of optically dense liquid nitrogen baffles over diffusion pumps prevents backstreaming to a large extent, but does not preclude contamination from accidents or a control failure. Turbomolecular pumps or ion pumps achieve oil free systems but are only practical for relatively small chambers. Large cryopumps were developed and checked out which do achieve clean pumping of very large chambers. These pumps can be used as the original pumping system or can be retrofitted as a replacement for existing diffusion pumps.

  15. Gene Expression Profiling in Viable but Nonculturable (VBNC) Cells of Pseudomonas syringae pv. syringae

    PubMed Central

    Postnikova, Olga A.; Shao, Jonathan; Mock, Norton M.; Baker, Con J.; Nemchinov, Lev G.

    2015-01-01

    Pseudomonas syringae infects diverse crop plants and comprises at least 50 different pathovar strains with different host ranges. More information on the physiological and molecular effects of the host inhibitory environment on the pathogen is needed to develop resistant cultivars. Recently, we reported an in vitro model system that mimics the redox pulse associated with the oxidative burst in plant cells inoculated with Pseudomonas syringae pv. syringae. Using this system, we demonstrated that oxidation of acetosyringone, a major extracellular phenolic compound induced in some plants in response to bacteria, rendered Pseudomonas syringae pv. syringae to a “viable but nonculturable” (VBNC) state. Here we performed a large scale transcriptome profiling of P. s. pv. syringae in the VBNC state induced by acetosyringone treatment and identified bacterial genes and pathways presumably associated with this condition. The findings offer insight into what events occur when bacterial pathogens are first encountered and host defense responses are triggered. The acquired knowledge will improve our understanding of the molecular mechanisms of stress tolerance. We believe that this is the first work on global gene expression profiling of VBNC cells in plant pathogenic bacteria. PMID:26733964

  16. Do Photovoltaic Energy Systems Effect Residential Selling Prices? Results from a California Statewide Investigation.

    SciTech Connect

    Hoen, Ben; Cappers, Pete; Wiser, Ryan; Thayer, Mark

    2011-04-12

    An increasing number of homes in the U.S. have sold with photovoltaic (PV) energy systems installed at the time of sale, yet relatively little research exists that provides estimates of the marginal impacts of those PV systems on home sale prices. This research analyzes a large dataset of California homes that sold from 2000 through mid-2009 with PV installed. We find strong evidence that homes with PV systems sold for a premium over comparable homes without PV systems during this time frame. Estimates for this premium expressed in dollars per watt of installed PV range, from roughly $4 to $6.4/watt across the full dataset, to approximately $2.3/watt for new homes, to more than $6/watt for existing homes. A number of ideas for further research are suggested.

  17. A High Power Density DC-DC Converter for Distributed PV Architectures

    SciTech Connect

    Agamy, Mohammed S; Chi, Song; Elasser, Ahmed; Harfman-Todorovic, Maja; Jiang, Yan; Mueller, Frank; Tao, Fengfeng

    2012-06-01

    In order to maximize solar energy harvesting capabilities, power converters have to be designed for high efficiency and good MPPT and voltage/current performance. When many converters are used in distributed systems, power density also becomes an important factor as it allows for simpler system integration. In this paper a high power density string dc-dc converter suitable for distributed medium to large scale PV installation is presented. A simple partial power processing topology, implemented with all silicon carbide devices provides high efficiency as well as high power density. A 3.5kW, 100kHz converter is designed and tested to verify the proposed methods.

  18. Spacecraft charging and plasma interaction implications for large space systems

    NASA Technical Reports Server (NTRS)

    Miller, E.; Stauber, M.; Rossi, M.; Fischbein, W.

    1978-01-01

    Specific discharge mechanisms, plasma interactions, and scale effects associated with very large spacecraft are studied. The large area, low density character, and extensive use of non-conducting materials is thought to have a major impact on the performance and survivability of many large space systems.

  19. Investigation of bias radiation effect on PV cell measurement

    NASA Astrophysics Data System (ADS)

    Huang, Xuebo; Quan, Chenggen; Chan, Joanne; Ng, Patrick

    2013-06-01

    Photovoltaic (PV) cells are photo-electrical devices that convert light energy directly into electricity through the photovoltaic effect. PV cell assemblies are used to make solar modules employed in a variety of ways ranging from space applications to domestic energy consumption. Characterisation and performance testing of PV cells are critical to the development of PV technologies and growth of the solar industry. As new solar products are being developed, its energy conversion efficiency and other critical parameters must be accurately measured and tested against globally recognised metrological standards. The differential spectral responsivity (DSR) measurement is one of the primary methods for calibrating reference PV cells. This is done by calculating its spectral responsivities through measuring the AC short-circuit current produced by a PV cell under a modulated monochromatic radiation and different levels of steady-state broadband bias light radiation. It is observed that different types of bias light source will produce different signal-to-noise levels and significantly influence measurement accuracy. This paper aims to investigate the noise sources caused by different types of bias light sources (e.g. xenon arc and tungsten-halogen lamps) and the relevant measurement uncertainties so as to propose a guideline for selection of bias light source which can improve the signal-to-noise level and measurement uncertainty. The DSRs of the PV cells are measured using a commercial DSR measurement system under different levels of bias radiation from 0 to 1 kWm-2. The data analysis and uncertainty evaluation are presented in this paper using experimental data and mathematical tools.

  20. An Evaluation of Knowledge Base Systems for Large OWL Datasets

    DTIC Science & Technology

    2004-01-01

    An Evaluation of Knowledge Base Systems for Large OWL Datasets Yuanbo Guo, Zhengxiang Pan, and Jeff Heflin Computer Science & Engineering ...present our work on evaluating knowledge base sys- tems with respect to use in large OWL applications. To this end, we have de- veloped the Lehigh...University Benchmark (LUBM). The benchmark is in- tended to evaluate knowledge base systems with respect to extensional queries over a large dataset that