Study On Renovation Of Lightning Protection System Of 220kV Power Supply Lines Of F Nuclear Power Station

With the rapid development of modern society,the demand for electricity has increased dramatically,and more and more nuclear power plants have been built at home and abroad.With the occurrence of nuclear accidents such as Cherno Obele and Fukushima,the society has increasingly realized the importance of nuclear safety.220 k V power supply system as the external power of F nuclear power plant,through the 220 k V transmission line(A line)to F nuclear power supply,it is mainly used for permanent guarantee F nuclear power plants,emergency and common auxiliary facilities of permanent power supply,when F nuclear power plant in the generator shut down after the loss of main power supply or emergency case,permanent,emergency and common auxiliary facilities of 220 k V switch power supply circuit of power supply,to ensure the safe operation of nuclear power plant F,so 220 k V power supply system should have good reliability.Since the operation of F nuclear power station,220 k V power supply lines have repeatedly experienced lightning trip-out events,the actual lightning trip-out rate of the lines exceeds the maximum value allowed by design,and the high lightning trip-out rate of the power supply lines will reduce the reliability of the external power supply of F nuclear power station,the external power supply is not reliable will affect the safe operation of F nuclear power plant.Therefore,the effective analysis of lightning parameters and lightning protection system performance of line a can provide scientific guidance for improving lightning protection design and reducing lightning failure rate of transmission line.In view of the great difference of Topography,geomorphology and characteristic parameters along the A line,this paper adopts the differential lightning protection evaluation method.The data of lightning location system from 2012 to 2016 are collected and analyzed.The average ground lightning density along a line is 6.9668 times/(km2·a),and the ground lightning density is high.According to the contrast analysis of the line conditions,the most suitable evaluation methods of lightning return stroke trip rate are geometry evaluation method and lightning shielding failure trip rate evaluation method is Monte Carlo method,the lightning flashover risk of 19.15% tower on a line is poor in lightning protection performance,and the probability of lightning flashover event is very high.Finally,according to the conclusion of risk assessment,a set of lightning protection improvement scheme is put forward on the basis of economy and Operability.The lightning trip rate of line a is expected to decrease by 70.1%.