500kV同塔双回输电线路反击耐雷性能分析

Research on Lightning Withstand Performance of 500 kV Double-circuit Transmission Line

与单回500 kV输电线路相比,同塔双回500 kV输电线路杆塔高度增加,引雷面积增大,将直接影响到线路的耐雷水平。文章依据先导发展闪络判据,模拟电弧的非线性特性,建立了绝缘闪络模型。利用电磁暂态仿真软件(ATP-EMTP),搭建了500 kV同塔双回输电线路反击耐雷性能仿真电路,分析了杆塔高度、冲击接地电阻和工频电压等因素对线路反击耐雷性能的影响。结果表明:杆塔高度增加后,线路反击耐雷水平显著降低;杆塔冲击接地电阻的增大,将导致线路跳闸率上升,在电阻较高的情况下尤为明显;同时工频电压对500 kV同塔双回输电线路耐雷性能影响尤为明显,因此,在500 kV同塔双回输电线路的设计中应充分考虑工频电压对线路耐雷性能的影响。

Compared with the 500 kV single circuit transmission lines on same tower, 500 kV double circuit transmission line tower has a higher height and bigger lightning area,it will directly affect the lightning withstanding level. Based on the pilot development of flashover criterion, in order to simulate the nonlinear characteristics of arc, we established the insulation flashover model. Based on the electromagnetic transient program ATP-EMTP 500 kV, we established a simulation model of the back-flashover performance for 500 kV AC transmission lines with double-circuit on single tower,and analyzed the impact of grounding resistance, the height of the tower, power frequency voltage to the back-flashover performance of line. The results show that： with the height of the tower increasing, the back-flashover performance of line will significantly reduced; the increasing of tower impulse grounding resistance will lead the tripping rate to rising, especially in the case of high resistance; At the same time, power frequency voltage has great influence on lightning withstand level of 500 kV transmission line tower. Therefore, it should be taken into account while designing.