超高压输电线并联电抗器的匝间短路保护

Turn-to-Turn Faults Protection of EHV Shunt Reactors

并联电抗器是超高压及以上等级输电系统中的关键设备,其运行状况对整个系统的安全运行起着决定性作用.针对目前并联电抗器故障率较高,尤其是匝间故障保护性能的缺陷,基于对并联电抗器匝间故障的序网图以及故障序分量的分析,提出了负序功率方向原理的新匝间短路保护.通过对并联电抗器的匝间故障、区内、区外接地故障以及由单相重合闸引起的非全相运行状态等情况的研究与仿真测试,表明负序功率方向保护不仅能在各种系统故障及运行情况下做出正确判断,更提高了对并联电抗器匝间故障保护的灵敏度.该保护利用故障负序分量计算实现,受励磁涌流等因素影响小,且其原理清晰,易于实现.

Shunt reactors are key equipments of EHV/UHV transmission lines and their operating state plays a decisive role in stability and power supply of EHV/UHV transmission system. On the basis of the analysis of sequence network and sequence components of shunt reactor turn-to-turn faults, a novel turn-to-turn fault protection, namely negative sequence power direction relay is proposed. Researches and simulation tests on turn-to-turn faults and ground faults of shunt reactor shows that the presented method can correctly judge whether the faults occurs in the protective zone or not and the sensitivity can be greatly improved. Furthermore, unbalance operating state of power system cannot reduce to the false trip of the relay, and inrush current has little impact on it.