Operational reliability evaluation of PV inverter considering relative humidity and its application on power system

With the penetration of renewable energy in the power system gradually increases, the importance of power electronics is growing up. The reliability of the power electronics should be taken seriously. This paper focuses on the operational reliability of photovoltaic (PV) inverters which is the most vulnerable in grid-connected PV systems and its application on the reliability evaluation of power systems. According to the field data, the effect of relative humidity is nonnegligible to the reliability of PV inverters. First, the real-time failure rate of components in PV inverters calculation method considering relative humidity is presented. Then the operational reliability evaluation of PV inverters is proposed. Finally, the reliability of power system including grid-connected PV systems is evaluated. It is aimed to explore a bottom-up approach to "effect factors-components-devices-system" reliability evaluation to establish a link between the components/devices and system. In this paper, the numerical examples verify the necessary of considering relative humidity in reliability evaluation. The evaluation results of PV inverters are used to the Roy Billinton Test System (RBTS). The analysis shows the results may affect the overall system performance.