Protection of Networked Microgrids Using Relays with Multiple Setting Groups

Abstract

The protection of multiple interconnected mi crogrids is a challenging task because of changes in the topology of the system. A microgrid can operate in an is landed mode or get connected to another autonomous mi crogrid or grid-connected microgrid or directly to the utility grid. The short-circuit currents can change widely because of the connection status of a microgrid in the system of multiple or networkedmicrogrids. In this article, a novel set ting groupsbasedschemeispresentedfortheprotectionof networked microgrids using directional overcurrent relays. The developed scheme can provide adequate protection to all microgrids under all possible interconnection among the microgrids and utility grid. A vector is generated for each possible interconnection of microgrids in the system to categorize them into four groups using k-means clustering. The optimum settings of relays considering all operational aspects of each group are calculated using a nonlinear pro gramming based algorithm. Based on the topological inter connections of microgrids in the system, one of the setting groups can be enabled using a low-bandwidth communi cation link. The proposed protection approach has been validated on a benchmark test system for networked micro grids. The suitability and the effectiveness of the developed settings of the relays have been analyzed adequately