Maximum Capacities of Distributed Generation in order to Avoid Failures of the Overcurrent Relay Coordination on a Distribution Networks

Abstract

The installation of a Distributed Generation (DG) in a distribution system often changes the direction and magnitude of current for normal and faulted conditions. The changes may affect the existing protection system hence it may not work as intended to after the installation. Since DG capacity is often small, it will not be economical to invest in the changing/replacement of the protection system. For that reason, this paper proposes a methodology to find maximum capacities of DGs that can be installed without cause failures to the existing protection operation and its coordination. A case study of a distribution network in West Sumatera is present to illustrate the methodology. The results show that the more downstream of buses from the grid, the less DG capacity that can be installed.