분산전원이 연계된 배전계통의 보호계전기 오동작 현상 분석

Abstract

A systemic investigation conducted through the experiment for the causes of malfunctions failure on over current ground relay of distribution system which is connected to distributed generation (wind turbines). Consequently, it was comprehended that the zero-sequence current flowing in the neutral wire induces this behavior. Distributed generation to the distribution system that uses linked to the wiring to the transformer primary side winding Y-Y KEPCO and neutral and ground because it uses the earthing, the zero-sequence current can be increased by an unbalance load current, harmonic current and imbalance of distribution system. As the solutions of these problems, the setting parameters change of protective relay, installation of zero-harmonics suppressor and directional over current ground relay were suggested.