Performance Evaluation of Various Risk Importance Measures for Large Scale Grid-Connected Solar Photovoltaic Systems

In recent years, solar power has substantially contributed to the expansion of sustainable energy sources worldwide. Reliability is essential for system design and long-term operation since it makes it possible to estimate risks and revenue losses. Reliability assessment is followed by determining critical components and faults in a photovoltaic (PV) system. A suitable Risk Importance Measure (RIM) is often used in a solar PV system to determine which basic events or failure modes significantly contribute to the failure or degradation of entire plant output and their criticality ranking. In this paper, the performance evaluation of four significant Risk importance measures, i.e., Risk Reduction Worth (RRW), Risk Achievement Worth (RAW), Fussell-Vesely (F-V), and Birnbaum Measure (BM), is carried out to decide the best suitable measure for Solar photovoltaic system to basic events ranking and thereby to find the most critical faults. The fault tree diagram of solar PV and the failure probability of system components are taken from the previous work of authors for analysis. The results show that Fussell-Vesely (F - V) importance Measure is the most suitable and computationally less expensive compared to other risk importance measures. It is also concluded that the Birnbaum method is not suitable for solar PV applications as all basic events formed Minimum Cut Sets (MCS).