500 kV同塔四回输电线路雷电反击特性研究

Study on Lightning Back Strike Characteristics of 500 kV Quadruple-circuit-co-tower Transmission Lines

500 kV同塔四回输电线路电压等级高、杆塔高、回路多,易发生雷电事故。以虞城换流站-玉山500 kV同塔四回输电线路中的主力杆塔SSZ直线塔为实例,分析了500 kV同塔四回输电线路的雷电反击特性。研究表明,随着雷电流幅值的增大,线路第一回、第四回、第六回线路相继发生闪络;随着杆塔呼高和杆塔冲击接地电阻的增大,反击耐雷水平快速降低,反击跳闸率迅速增加;杆塔横担波阻抗对500 kV同塔四回输电线路的反击耐雷水平影响较小。

The 500 kV quadruple-circuit-co-tower transmission lines feature high voltage level,multiple circuits,and high tower height,and are prone to lightning back strikes.This paper reports a case analysis conducted on the SSZ tangent tower as the main tower type in an actual 500 kV quadruple-circuit-co-tower transmission lines between Yucheng Converter Station to Yushan,to study the lines′lightning back strike characteristics.The results show that with the increase of lightning current amplitude,lightning back strike occurs in succession in the first,the fourth and the sixth circuits.With the increase of tower height and tower impact grounding resistance,lightning resistance level decreases rapidly,and tripping rate increases rapidly.In addition,the influence of cross load impedance on lightning resistance of 500 kV quadruple-circuit-co-tower transmission line is ignorable.