计及多脉冲回击电流及电晕电流效应的输电线路耦合雷电过电压特性

Coupled Lightning Overvoltage Characteristics of Transmission Lines Considering Multi-Pulse Return Stroke Current and Corona Current Effect

目前在输电线路耦合雷电过电压的理论计算研究工作中,大多均考虑单一回击电流源的情况,忽视了现实中闪电主要以多脉冲的形态存在居多,忽略了导线电晕放电效应对过电压抑制作用的影响。因此,对双Heidler回击电流源进行改进,建立一次放电过程包含3个峰值电流的多脉冲电流源,并对单脉冲作用下电晕放电模型进行优化,使其满足多脉冲作用下电晕放电效应,同时采用leap-frog算法对Maxwell方程组进行二阶高精度差分,提高其模型的稳定性。研究结果表明:单脉冲作用下所计算出的过电压峰值与IEEE标准结果相对误差仅为2.11%,同时多脉冲使线路耦合过电压峰值较单脉冲抬升17.08%;电晕效应抑制了多脉冲作用下输电线路过电压峰值7.29%;与雷击点较远相位导线耦合的过电压峰值与离雷击点最近相线过电压相差17.5%。研究结论能够为输电线路差异化防雷设计提供更加精确的理论支撑。

At present,in the theoretical calculations and researches of coupled lightning overvoltage of transmission lines,most of them consider the situation of single return stroke current source and ignore that lightning mainly exists in the form of multi-pulse in reality.Many studies ignore the influence of conductor corona discharge effect on overvoltage suppression.Therefore,this paper improves the double Heidler return stroke current source,establishes a multi-pulse current source with three peak-currents in one discharge process,and optimizes the corona discharge model under single pulse to meet the corona discharge effect under multipulse.At the same time,the leap-frog algorithm is used to make the second-order high-precision difference of Maxwell equations to improve its model stability.The results show that the relative error between the overvoltage peak calculated in this paper and the IEEE standard result under the action of single pulse is only 2.11%.At the same time,the line coupling overvoltage peak is 17.08%higher than that of single pulse;the corona effect suppresses the peak overvoltage of transmission line under multi-pulse action by 7.29%;the peak value of overvoltage coupled with the phase conductor far from the lightning point is 17.5%different from the overvoltage of the phase conductor nearest to the lightning point.The conclusions of this paper can provide more accurate theoretical support for differential lightning protection design of transmission lines.