500kV交流同塔四回线路的绕击耐雷性能

为解决架设500kV同塔四回输电线路高杆塔时的雷害问题,运用改进的电气几何模型法及电磁暂态仿真程序计算了杆塔的绕击耐雷性能,得出了不同杆塔呼称高度、地面倾角、杆塔保护角和击距系数等参数时的绕击跳闸率并且详细分析了地面倾角、杆塔高度等参数对绕击跳闸率的影响。最后提出了改善500kV同塔四回绕击耐雷性能的措施,即在实际工程中,从减小杆塔高度、避雷线采用负保护角、增加绝缘子片数以及尽量避免在地面倾角较大的地点架设输电线路等几个方面综合考虑。

Characteristic of Lightning Shielding Failure for 500 kV AC Transmission Lines with Quadruple-Circuits on One Tower

The lightning performance calculation of back flashover for 500 AC transmission lines with Quadruple-Circuits on single tower are obtained by the EGM(Electro-geometrical Model).EMTP(Electromagnetic Transients Program)and MATLAB;The shielding failure trip-out rates in different conditions are figured out through changing the nominal height of the tower,the ground elevation,the angle of protection and the striking distance factor and other parameters and the influences of ground elevation and height of the tower on failure trip-out rate are analyzed in detail.The result shows that shielding failure trip-out rate increases with increase of the nominal height of the tower when maintaining the ground elevation and angle of protection,with increase of the ground elevation when maintaining height of the tower and angle of protection,with increase of the angle of protection when maintaining height of the tower and ground elevation.The trip-out rate reduces rapidly with decrease of striking distance factor.The smaller striking distance factor is,more rapidly the trip-out reduces.The measures for improving lightning performance of 500 kV AC transmission lines with Quadruple-Circuits are put forward at the end,that is reducing height of towers,using negative angle of protection,using more insulators and avoiding to set up transmission lines where the ground elevation is big.