LAUSR

Abstract The performance of photovoltaic (PV) modules gradually declines as the operational time continues due to the impacts of workload and environmental factors. This performance degradation process is dynamic and random. Hence, two stochastic process models, exponential dispersion process with fixed effect and with random effect are proposed to describe this degradation law. With these two models, the procedure for evaluating the reliability of PV modules is illustrated based on a practical case. The proposed model is demonstrated to be rationality and applicability for the PV modules through three common information criteria and Kolmogorov–Smirnov test. Due to the exponential dispersion process includes some common stochastic process, e.g. Wiener process, Inverse Gaussian process and Gamma process, which makes the proposed models have a wide range of applications. The proposed models can provide references for the warranty life, maintenance of PV modules.