Study on influence of lightning arrester configuration on VFTO in 420kv GIS substation overvoltage in 420kv GIS substation transformation project

Abstract

Lightning impulse overvoltage is the main factor to determine the insulation level of substation, and the insulation coordination between the insulation level of the protected electrical equipment and the arrester of the protection device is the most basic and important insulation coordination in the power system. In this paper, the working principle, characteristics and lightning current simulation of zinc oxide arrester are described. Then, taking a 420kV gis substation as an object, an electromagnetic transient simulation platform is built by using electromagnetic transient program (EMTP-ATP), which is used to simulate 420kV When the 400 kV side of GIS Substation is struck out of the line tower by lightning, the insulator flashover occurs, and then it invades the substation along the transmission line to generate Lightning Overvoltage on the equipment. Considering the operation mode of single line single bus single transformer with the most serious overvoltage, the overvoltage waveform of the voltage transformer at the outlet end and the main transformer port of the 420kV GIS Substation is obtained under the given arrester configuration scheme. Through calculation and analysis, the design meets the requirements of specifications and engineering practice.