Reliability Assessment of PV Inverters with Battery Systems Considering PV Self-Consumption and Battery Sizing

To ensure the cost-competitiveness of Photovoltaic (PV) with integrated Battery Energy Storage Systems (PV-BESS), a highly reliable operation is demanded. The PV inverter has been reported as one of the reliability-critical components in the system, whose failures can lead to a severe negative impact on the cost of PV energy. Therefore, improving PV inverter reliability has high potential for the cost reduction of the PV-BESS. This paper thus investigates the impact of battery operation on the PV inverter reliability. A 6-kW residential PV-BESS in Germany is considered, where a self-consumption scheme is adopted. The evaluation results reveal that the reliability of the PV inverter is strongly affected by the battery operation. More specifically, the PV inverter loading is decreased significantly during the battery charging, which results in an improvement in the PV inverter reliability. In addition, the battery system parameters, such as battery capacity and battery converter power rating, also affect the PV inverter loading, whose impact on the PV inverter reliability has been analyzed.