Reliability and electrical safety of grid-connected household PV systems: Data-driven risk analysis and insights

Home photovoltaic generators (PVGs) offer many benefits, including reduced energy costs and environmental sustainability. Ensuring electrical safety in PVGs is crucial to prevent hazards such as electric shock, fires, and system malfunctions. As PVG components age, the likelihood of electrical issues increases. This research assesses the reliability of key components and evaluates the risk of electric shock in household PVGs using fault tree analysis. Due to limited data on failure rate of small-scale PVGs, component reliability was analysed based on survey feedback from 85 Norwegian PVG owners. To gain deeper insights into home PVG vulnerabilities, a Simulink model was applied to simulate various faults, including failures in PV modules, inter-string connections, MOSFETs, and both the DC and AC sides of the inverter. The findings indicate that inverters are the most failure-prone components in household PVGs while the residual current devices (RCDs), as critical protection units, also lose reliability over time. These findings underscore the critical importance of implementing a comprehensive suite of protective measures in PVG systems to ensure both safety and reliability, as well as importance of proactive condition monitoring, particularly for the inverter, battery charger, RCD, and insulation resistance.