Evaluation of Operational Reliability of a Microgrid Using a Short-Term Outage Model

Abstract

Island-capable microgrids can potentially improve customer reliability, but protection-related issues can adversely affect this reliability benefit. At the same time, average annualized indices often do not effectively convey a complete picture of load-point reliabilities in microgrids integrated with multiple weather-dependent microsources. The primary goal of this work is to investigate the impacts of protection system and operating conditions on the reliability indices of a microgrid. The proposed method utilizes a short-term outage model that quantifies the relationship between state variables and the outage rate of component. A hybrid approach is proposed, which combines scenario selection and enumerative analysis. Simulations on a test system illustrate the dependence of operational reliability on factors such as local meteorological conditions, correlation between variable generation and loads, as well as the effects of protection system operations. Finally, some recommendations on the parameter settings of protection system are provided to enhance the system reliability.