RESEARCH OF THE ATMOSPHERIC OVERVOLTAGES IN A SUBSTATION BY USING ATP-EMTP

Abstract

In this research, the author considers the factors affecting the magnitude of the overvoltage acting on the insulation of the 110 kV Son La substation by the electromagnetic transients program ATP-EMTP. Research results show that overvoltage (pulse magnitude and voltage wavefront) propagated from the line to the substation depends on the parameters of the lightning current, the location of the lightning strike and the grounding resistance of the pole. When the lightning current is greater than 200 kA, it will generate an overvoltage greater than the basic impulse insulation level (BIL) of electrical equipement in the substation. Lightning strikes the last tower or the last span, the overvoltage generated and propagates into the substation with large parameters. On the other hand, the grounding resistance of the tower foot. In addition, the results of the study are used to enhance our understanding about the factors that contribute to overvoltage in the substation which enables us to provide better protection for the Substation insulation.