Research On Lightning Over-voltage Of 1000kV GIS Substation

Along with the rapid development of UHV grid, more and more attention is paid to the safe operation problems of UHV. It is necessary to analysis the factors that affect lightning overvoltage of substations and get a configuration scheme of substations through the simulation, which simulates the progress of lightning wave from transmission lines to substations for less lightning accidents. The primary contents can be summarized as follows:First, the simulation model is set up by using EMTP, which based the occurrence mechanism of the lightning overvoltage and the actual situation of one UHV GIS substation in North China. The simulation model is combined the incoming transmission lines, which includes transmission line models considering corona?line tower models?insulator string flashover models and lightning current models, with GIS substation.Then, the influence from factors of the incoming line and distribution equipment in substations to the lightning overvoltage are considered, respectively. The incoming line factors include different lightning strike spots, lightning current gradient, power frequency voltage and phase angle,impulse grounding resistance and impulse corona.the factors of distribution equipment in substations include the length of gis trachea, distance between arrester and transformer,the position of electromagnetic voltage transformer in gis bus, and high voltage reactor. The model in this paper can simulate the lightning overvoltage on GIS substation more factually. This paper attempts to use grey comprehensive algorithm to sort the incoming line factors that can affect back striking and shielding failure of UHV GIS substation with their influence degree. The analysis shows that for us the lightning current and grounding resistance are the main influence factors in the case of back striking; lightning current and power frequency phase angle are the main influence factors in the case of shielding failure. This result fit well with other simulation results.At the end of this paper, application of surge arresters of UHV GIS substation is researched. The research results of this paper can offer reference for the improvement of lightning protection level of current UHV GIS substation and the lightning protection design of newly-built substations.