Research On Lighnting Comprehensive Protection Performance Of500KV Double Circuit Transmission Lines

The lighting trip-out rate always keeps a high value; there is a close contact between trip-out rate of500kV transmission lines and stability of the grid.To synthetically analyze lightning protection performance of500kV transmission lines, mechanism of lightning strike accident and research current situation of lightning protection are elaborated, including some newest protection methods such as the lightning location system, Lightning warning technology.Based on travelling wave method, the insulator strings’flash over state are simulated when the amplitude of lightning current is100kA,150kA,200kA by ATPdraw; and the effects of those factors are analyzed, such as structure of tower, grounding resistance, insulation level, tower surge impedance to lightning withstand level of lightning back striking.Based on the reserved EGM and considered the effect of wind deflection angle to shielding failure, shielding failure trip-out rate is researched; the differentiation theory and strategy of lightning protection are recommended; various of different factors to the importance of lightning withstand level also are studied.The effects of those factors are researched, such as ground obliquity, expression of striking distance, insulation level, external-insulation-selection method, tower’s height, terrains and topographic features, wind deflection angle to the shielding failure trip-out rate; reasons of the value of lightning trip-out rate are analyzed, which is not low including anthropogenic factor, unreasonable protection angle, grounding resistance which doesn’t meet the requirement, lightning activity lever which is increasing year by year, insufficiency of insulation level.