长距离特高压交流输电线路单相接地故障过电压研究

Single-phase grounding overvoltage of long-distance UHVAC lines

分析单相接地故障过电压的影响因素,得出使单相接地过电压最大的条件,基于此在不同的线路高抗补偿度以及沿线避雷器的布置方式下,探讨了不同线路分段方式下单相接地故障过电压不超过限制水平时线路能够达到的最大长度,并对避雷器和高抗限制过电压的效果进行了对比。研究结果表明,避雷器限制长线路单相接地故障过电压的效果不及高抗;对于分3段的线路,整条线路总长度最大不超过1 300 km时,单相接地故障过电压不会超过限制水平,单段线路的最大长度可达500 km;对于分4段和5段的线路,总长度分别不超过1 400 km、1 600 km时,过电压不会超过限制水平,单段线路的最大长度均为400 km。

The influencing factors of single-phase grounding overvoltage are analyzed and the conditions causing the maximum overvoltage are obtained. With different compensation degrees of HV shunt reactor and different disposals of MOA （Metal Oxide Arrester）, the maximum length of UHVAC line is discussed for different segment modes,under which the single-phase grounding overvoltage will not surpass the limitation. The effect of MOA on overvoltage suppression is compared with that of HV shunt reactor,which shows the latter has better effectiveness. For three-segment lines,the maximum total line length may reach 1 300 km while that of single segment may reach 500 kin. For four-segment and five-segment lines,the maximum total line length may reach 1400 km and 1600 km respectively while that of single segment may reach 400 kin.