500kV同塔双回线路过电压计算及杆塔操作冲击最小空气间隙选择

Overvoltage Calculation and Selection of Switching Impulse Minimum Air Gap for 500 kV Double-Circuit Transmission Line on Same Tower

为了确定同塔双回输电线路操作过电压最小空气间隙,运用ATP计算了500kV太安-黄坪同塔双回空载线路合闸过电压、单相重合闸过电压、故障解环操作过电压,通过比较获得了相地2%最高过电压为1.82p.u,出现在线路末端距太安22%处。开展了500kV双回线路真型塔中相I串对下侧横担、下相I串对塔腿间隙操作冲击试验,获得了间隙距离与操作波放电特性曲线,结合最高过电压水平计算了中相I串对下侧横担、下相I串对塔腿最小安全间隙为2.75m和2.78m,为500kV同塔双回线路操作过电压间隙选择提供了依据。

In order to determine the minimum air gap of switching overvohage for double-circuit transmission line on same tower, the author calculates closing overvohage on unloaded line, single- phase reelose overvohage, fault interruption overvohage in ATP for Taian-huangpin 500 kV doublecircuit transmission line, the result shows that phase-ground 2% maximum overvoltage is 1.82 p.u and the location is 22% far from the end of taian line. The switching impulse test of gap for middle-phase conductor to lower cross-arm and lower-phase conductor to tower is developed respectively on tower of 500 kV double-circuit transmission line, and the discharge curve of switching impulse is obtained. According to the highest overvoltage computation result, the minimum air gap is 2.75 m for middle- phase conductor to lower cross-arm and 2.78 m for lower-phase conductor to tower, it provides evidence for switching overvoltage gap distance selection of 500 kV double-circuit transmission line.