Reliability Evaluation in Microgrids with Non-exponential Failure Rates of Power Units

This article explores the impacts of non-exponentially distributed failures on reliability of microgrids. Failure rate of some components such as power electronic converters is not constant, while they play a major role in microgrids. Consequently, their failure characteristics will affect the microgrid reliability. Hence, the conventional reliability evaluation approaches based on mean time to failure may introduce inaccurate inputs for decision making in planning and operation of microgrids. In this article, different approaches are employed for evaluating the reliability of microgrids with non-constant failure rates. The obtained results indicate that the system reliability remarkably depends on the failure characteristics and considering mean or steady-state probabilities instead of failure statistics may introduce erroneous reliability prediction results. Numerical case studies are provided to illustrate the impacts of failure characteristics on the availability of single power units as well as the reliability of microgrids.