Reliability Evaluation of Grid-Connected Photovoltaic Power Systems

This study presents a systematic way to evaluate reliability performance of large grid-connected photovoltaic (PV) power systems considering variation of input power and ambient-condition-dependent failure rates of critical components including PV modules, inverters, and capacitors. State enumeration is used to analyze real-life grid-connected PV systems. Ambient-condition-dependent failure rates of major components in PV systems are formulated and incorporated in reliability analysis. A series of reliability indices are defined to quantify PV systems´ reliability performance. In addition, sensitivity analyses are extensively conducted to investigate the impact of different factors on the performances of PV power systems. Test results on a practical 20-kW PV project are presented to demonstrate the effectiveness of the proposed method.