基于时域有限差分法的双回路直线转角塔雷电冲击响应特性研究

Research on Lightning Surge Response of Double-circuit Straight Angle Tower through FDTD

基于时域有限差分法分析了雷击双回路直线转角塔时杆塔电压的分布特点,研究了土壤电阻率和呼高对杆塔雷电冲击响应特性的影响,同时与基于多波阻抗模型的杆塔雷击响应计算结果进行对比分析。结果表明,雷击塔顶时,相同高度处横担宽度越大,过电压越严重,越容易闪络;横担过电压随着土壤电阻率的增加而增大,随着横担高度的增加,所受影响逐渐减少;横担过电压随着呼高的增加而增大,且不同高度横担所受的影响几乎一致;基于多波阻抗模型计算得到的横担电压大于数值仿真计算结果,故采用多波阻抗模型将使防雷分析结果偏严苛。

Based on FDTD method, this paper analyzed the voltage distribution of double-circuit straight angle tower when stroke by lightning, and studied the influence of soil resistivity and tower height to lightning surge response of the tower.Lightning surge response of the tower based on FDTD was also compared with the results analyzed by multi-wave impedance model. The results showed that more severe overvoltage would be appeared on the cross-arm with greater width at the same height when the lightning stroke the top of the tower, which made the insulator easier to flash. The overvoltage on the crossarm increased along with the soil resistivity and its height increased, while the impact reduced gradually. The overvoltage on cross-arm increased with the increase of tower height, and the impact is almost the same to the cross arm at different height.The overvoltage calculated by multi-wave impendence model was greater than that based on FDTD, so the former model would give a harsher result.