The Lightning Inrush Overvoltage Portection Of 500kV Substation

The lightning inrush overvoltage is the main reason for lightning accident of substations and power plants. So how to compute and simulate the lightning inrush overvoltage of substations and power plants has important significance: the lightning protection performance of substations and power plants can be valued by the compute result, and chose credible and economical lightning protection method.500kV substations have momentous status in power system, once they have some lightning accident, there will be a power pause in a large area. And the electric equipments in substations, such as transformer, have no resume ability in its' inner insulation, if they are destroyed by lightning, the rehab work will be very hard, so can cause serious result. So it is especially necessary to study on the lightning inrush overvoltage of 500kV substations.The lightning inrush overvoltage is influenced by the voltage-second characteristics of the insulators of the incoming lines, the impulse grounding resistance of tower, the mode of operation of the substation, and the lightning discharge place. All of influence facts need be considered when computing and simulating. And the lightning current source, the electric equipments of the incoming lines and substations need to be simulated as accurately as possibly. The equipments include: lightning current source, insulator, conductor, MOA, bus, transformer, and so on.When study, the lightning current is considered a current source placed at the top of the tower, and the insulator's flashover is simulated by the TACS function in EMTP, to compute and analysis the lightning overvoltage on electric equipments caused by the lightning current which enter the conductor after the insulator's flashover.This paper takes the Shimian 500kV GIS substation and Ya'an 500kV AIS substation as sample; combine the substation and the incoming lines to a whole net work. Taking the impulse voltage-second characteristics of insulator and the impulse grounding resistance of tower into account, and considering near discharge and far discharge, adopting the current electro-magnetic transient program(EMTP) to compute and study the lightning inrush overvoltage of 500kV substations, some lightning protection characteristic of GIS and AIS substations be obtained, and confirm a reasonable lightning protection method, and analysis the influence effect of the influence facts. All conclusions can be referred by the design of substations. In EMTP,...