Assessing the impacts of microgrids on composite power system reliability

With the advent of microgrids and their integration in power systems, the analysis of their impacts on power system planning, operation, and control becomes an important issue to be addressed. In this paper, we focus on assessing the benefits of microgrids on composite power system reliability. The realization of these benefits call for the optimal coordination among the three energy sources within microgrids, namely renewable energy conversion, energy storage and micro-turbine generation. This coordination is modeled when applying sequential Monte Carlo simulations whose objective is to assess the risk of cascading failure due to relay overtripping, short-circuits induced by overgrown vegetation, voltage sags, line and transformer overloading, transient instabilities, voltage collapse, among others. Comparison of the reliability index values is carried out on the Roy Billinton Test System (RBTS) with and without microgrids. It is shown that microgrids significantly improve the reliability of the system.