时域有限差分法配电线路耦合雷电过电压求解及空间变化特征分析

Analysis of spatial variation characteristics and calculation of coupled lightning overvoltage of distribution line based on FDTD

电力系统中配电线路一般裸露在空气中,极易遭受雷电过电压侵害造成供电中断。针对配电线路耦合过电压的空间分布特征问题,采用时域有限差分方法(FDTD)对雷击点相对于配电线路中点、端点位置处的雷电感应过电压进行计算,从而对耦合的雷电过电压峰值时间及空间变化趋势进行研究。仿真结果表明:雷击点处于配电线路中部时,产生峰值28.07kV的雷电过电压,且线路中点位置处束缚的感应电荷最多,随后由中点迅速地向线路两端移动。而雷击点处于线路两端时,产生峰值32.74kV的雷电感应过电压。

In the power system,the distribution lines are usually exposed in the air and vulnerable to power supply interruption caused by lightning induced overvoltage.In view of the spatial distribution characteristics of coupling overvoltage of the transmission line,the FDTD is used to simulate the lightning induced overvoltage on the location of the lightning point relative to the middle point and the end point of the distribution line,and the peak time and the spatial trend of the overvoltage are studied.The simulation results show that when lightning strikes on the middle part of grid line,the peak value of the lightning overvoltage is 28.07 kV.The induced charge of the neutral point at the middle of the line is the largest,and the bound electric charge at the midpoint position moves rapidly to the two ends.The over voltage peak of the lightning stroke relative to the end point of the line is 32.74 kV.