On the temperature dependence of photovoltaic module electrical performance: a review of efficiency/ power correlations

https://minds.wisconsin.edu/bitstream/handle/1793/7602/desoto04.pdf?sequence=1

Improvement and validation of a model for photovoltaic array performance

As photovoltaic penetration of the power grid increases, accurate predictions of return on investment require accurate prediction of decreased power output over time. Degradation rates must be known in order to predict power delivery. This article reviews degradation rates of flat-plate terrestrial modules and systems reported in published literature from field testing throughout the last 40 years. Nearly 2000 degradation rates, measured on individual modules or entire systems, have been assembled from the literature, showing a median value of 0·5%/year. The review consists of three parts: a brief historical outline, an analytical summary of degradation rates, and a detailed bibliography partitioned by technology. Copyright © 2011 John Wiley & Sons, Ltd.

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Photovoltaic Degradation Rates—an Analytical Review

This document summarizes the equations and applications associated with the photovoltaic array performance model developed at Sandia National Laboratories over the last twelve years. Electrical, thermal, and optical characteristics for photovoltaic modules are included in the model, and the model is designed to use hourly solar resource and meteorological data. The versatility and accuracy of the model has been validated for flat-plate modules (all technologies) and for concentrator modules, as well as for large arrays of modules. Applications include system design and sizing, 'translation' of field performance measurements to standard reporting conditions, system performance optimization, and real-time comparison of measured versus expected system performance.

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Photovoltaic array performance model.

Traditional electric power systems are designed in large part to utilize large baseload power plants, with limited ability to rapidly ramp output or reduce output below a certain level. The increase in demand variability created by intermittent sources such as photovoltaic (PV) presents new challenges to increase system flexibility. This paper aims to investigate and emphasize the importance of the grid-connected PV system regarding the intermittent nature of renewable generation, and the characterization of PV generation with regard to grid code compliance. The investigation was conducted to critically review the literature on expected potential problems associated with high penetration levels and islanding prevention methods of grid tied PV. According to the survey, PV grid connection inverters have fairly good performance. They have high conversion efficiency and power factor exceeding 90% for wide operating range, while maintaining current harmonics THD less than 5%. Numerous large-scale projects are currently being commissioned, with more planned for the near future. Prices of both PV and balance of system components (BOS) are decreasing which will lead to further increase in use. The technical requirements from the utility power system side need to be satisfied to ensure the safety of the PV installer and the reliability of the utility grid. Identifying the technical requirements for grid interconnection and solving the interconnect problems such as islanding detection, harmonic distortion requirements and electromagnetic interference are therefore very important issues for widespread application of PV systems. The control circuit also provides sufficient control and protection functions like maximum power tracking, inverter current control and power factor control. Reliability, life span and maintenance needs should be certified through the long-term operation of PV system. Further reduction of cost, size and weight is required for more utilization of PV systems. Using PV inverters with a variable power factor at high penetration levels may increase the number of balanced conditions and subsequently increase the probability of islanding. It is strongly recommended that PV inverters should be operated at unity power factor.

Grid-connected photovoltaic power systems: Technical and potential problems—A review

This paper deals with the technology transfer of a specific photovoltaic (PV) module characterization procedure from Sandia National Laboratories (Sandia) to Arizona State University Photovoltaic Testing Laboratory (ASU-PTL). This effort was intended to meet industry requests for independent module performance testing that provides the parameters (coefficients) required by the Sandia performance model. The objective of this work was two fold: (i) implement Sandia's experimental methodology at ASU-PTL to collect and analyze sunrise-to-sunset module performance data; and (ii) validate Sandia's performance model by comparing the modeled performance based on analysis of daylong data sets with performance determined using traditional standardized procedures. This paper reports lessons learned as well as the successful completion of this effort.

Implementation and Validation of Sandia Outdoor Photovoltaic Test Method and Performance Model at Arizona State University

A comprehensive evaluation and experimental optimization of the FireFly{trademark} 600 off-grid photovoltaic system manufactured by Energia Total, Ltd. was conducted at Sandia National Laboratories in May and June of 2001. This evaluation was conducted at the request of the manufacturer and addressed performance of individual system components, overall system functionality and performance, safety concerns, and compliance with applicable codes and standards. A primary goal of the effort was to identify areas for improvement in performance, reliability, and safety. New system test procedures were developed during the effort.

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William E. Boyson

Papers

Implementation and Validation of Sandia Outdoor Photovoltaic Test Method and Performance Model at Arizona State University

Experimental optimization of the FireFly 600 photovoltaic off-grid system.

Photovoltaic system performance characterization methodologies.

Comparison of Photovoltaic Module Performance Measurements simulation tools used to predict the energy production of photovoltaic systems

Long-term performance measurements and reliability assessment of 8 PV arrays at Sandia National Laboratories.