Study On The Measures For Lightning Trip-out Of Multi-circuit Transmission Lines On The Same Tower

With economic development,expanding of the grid scale,using multi-circuit transmission line is effective way to improve the utilization of the line corridor and solve land resources shortage,in the economically developed,densely populated areas.Over the years,lightning has been the main cause of transmission line fault,especially located in multi-circuit transmission line with higher tower leading to larger probability of being struck by lightning.Once multi-circuit lightning flashover,due to the N-1 power back requirements,power outages would be implemented,which caused a great impact on the grid.Especially for the China Southern Power Grid,the total length and proportion of multi-circuit transmission lines is increasing every year,posing a big challenge on grid's safe operation.Therefore,studying the mechanism of multi-circuit transmission lines,and exploring protective measures to reduce the rate of multi-circuit flashover,is of great research value and practical significance.This paper based on ATP-EMTP software,the simulation model with different voltage class of multi-circuit transmission lines would be created to created,to carry out research on sensitive factors related models,including the tower base,the height of front and rear tower,grounding resistance of front and rear tower grounding,span,and the model would be checked by combined with the simulation results in the literature and monitoring results in real;the typical 220 kV multi-circuit circuit transmission line is chosen,lightning performance was simulated under influence of grounding resistance,tower height,insulation level,phase sequence arrangement,to figure out the law of how these factors act on lightning performance;then further research is conducted on protection measures anti multi-circuit flashover,the measures is included that ground resistance lowering,unbalance insulation,coupled ground-wire,line arresters installing,combine with comprehensive and differentiated lightning protection,a protection measures technical and economic evaluation methods is proposed,and rehabilitation programs for anti lightning is developed for Yitian and Fupu multi-circuit transmission lines.