Laboratory Prototype to Understand Miscoordination of Relays in Radial Network in the Presence of Distributed Generation

Abstract

Due to incorporation of Distributed Generation (DG), the traditional protection scheme for electric power distribution system lost its radial nature and behaves more like multifeed transmission system. A laboratory prototype of three phase radial distribution network containing DG is presented in this paper. By executing number of single line-to-ground faults at different locations in various sections of radial distribution network containing DG, numbers of maloperations due to miscordination of relay have been observed by the authors. In this paper, the impact of high resistance fault in the radial distribution network in the presence of DG has been analyzed. Time of operations of all the relays of radial distribution network obtained from the developed laboratory prototype for different fault locations in various sections have been found to be in close conformity with the theoretical values obtained using an IEC standard relay characteristics equation.