Simulation Research On The Lightning Invasion Waves Overvoltage In 500kV Substation

At present,500kV power grid is the main transmission network in China, and 500kV substation is generally hub substation, playing a very important role. It can be used as a connection of adjacent power system and can also be used as the main power source for the next level of power network. The lightning damage is the biggest threat to the substation, especially the lightning invasion waves, which can add tens of thousands of volts to the substation electrical equipment, resulting in much serious equipment damage and property losses. Therefore, it is necessary to do comprehensive research on overvoltage of equipment of the 500kV substation caused by lightning invasion wave.This article is to review the development of 500kV substation, source of lightning disaster and present situation of the domestic and foreign research on lightning invasion wave overvoltage. The principle of lightning invasion wave overvoltage is analyzed theoretically, and the various factors that affect the overvoltage level are studied. Taking a 500kV substation in Guangxi for example, we consider substation and line segments as a whole, and establish the simulation calculation model of equipment using electromagnetic transient analysis software ATP-EMTP. Besides, simulation calculation and analysis of the equipment overvoltage caused by lightning invasion wave are performed.The simulation results indicate that the running operation influence the over voltage level of the substation equipment, especially in single line single bus single transformer when the equipment overvoltage is highest; the different lightning point makes the different overvoltage level of the equipment, generally, the strike point distance substation entrance farther, the equipment over voltage is lower; the tower impulse grounding resistance have great influence on the overvoltage of main transformer, voltage of main transformer increases with the increase of the tower impulse grounding resistance; the electrical distance between the main transformer and arrester will directly affect the protection effect, the electrical distance is farther, and the protection effect is worse; the bus is additionally arranged on a group of arrester equipment can effectively reduce the overvoltage level.In this paper, the influence of lightning shielding failure on the overvoltage level of substation equipment is also discussed. The simulation results show that the voltage amplitude on each device is much smaller than the lightning impulse insulation level, and the current in the lightning arrester is much less than the discharge current of the arrester. Equipment can be safe and reliable operation. Finally, the configuration scheme of the lightning arrester is discussed, the advantages and disadvantages of various schemes are analyzed in detail, and the safe and reliable measures for lightning protection are put forward.