750kV同塔双回输电线路雷击塔顶感应电压的数值计算

架空输电线路的雷击感应电压计算是电力线路绝缘设计、采取防雷保护措施的基础计算。对雷击750kV同塔双回输电线路塔顶产生感应电压的暂态过程进行了分析,采用电磁场数值分析方法,建立了回击电流模型和线路耦合模型,精确地计算了感应电压值。计算结果表明,感应电压随时间变化非常快,所以在计算雷击塔顶的耐雷水平时,如果把感应电压以一个恒定值的方式计入,必然会产生一定的误差,应该考虑感应电压的暂态过程。

Calculation of Lightning Induced Voltage on 750kV Double Circuit Transmission Lines on the Same Tower when Lightning Strikes Tower Top

Lightning induced voltage on overhead transmission lines is related to the basic calculation of insulation design and lightning protection measure.The author presents analytical expressions for transient process of lightning-induced voltages when lightning strikes the tower top of 750 kV double circuit transmission lines on the same tower.The procedure makes use of a lightning return-stroke model for the calculation of the lightning electromagnetic field and a coupling model already presented in the literature based on the transmission line theory for field-to-overhead line coupling calculations.The result of calculations shows that variation of lightning induced voltage with time is very fast.There is a consequential error if we still regard lightning induced voltage as invariable to calculating of lightning withstand level.So the transient process of lightning induced voltage should be taken into account.