雷电电磁脉冲对架空电力线的耦合效应

Coupling effects of LEMP on aerial multiconductor power lines

从传输线模型出发,通过建立雷电回击通道、大地和电力线系统一体化模型,采用时域有限差分法计算得出雷电回击电流的近场分布,将场值代入离散的传输线方程后,计算了架空电力线终端的感应过电压.通过对多导体架空线和单导体线终端感应过电压的分析,发现由于其它导体的存在,多导体系统中单根导体两端的感应电压峰值比相同高度处单一导体两端的感应电压峰值低10%～20%;并且对于垂直导体结构,最小感应电压产生在距离地面最近的导体上;而对于水平导体结构,最小感应电压产生在中间导体上.

Based on the transmission line model, this paper proposes a method that integrates the lightning return stroke channel, the earth and the overhead lines together for calculating the lightning-induced voltages on overhead lines. The finitedifference time-domain （FDTD） method is used to obtain the electromagnetic field values near a cloud-to-ground lightning return stroke channel, and then these field values are put into the discretized transmission line equations to calculate the induced voltage at the end of overhead lines. Analyses show that the induced voltage on one conductor of the multi-conductor loaded lines is affected by the presence of other lines, and the voltages induced on each of the line conductors are generally 10%-20% lower than those corresponding to a single conductor located at the same height. The minimum induced voltage is generated on the line conductor nearest to the ground for vertical configuration of the three lines, while on the middle line conductor for horizontal configration of the three lines.