330kV高压电抗器匝间保护误动原因分析

安装了分相式高压并联电抗器的高压输电线路,在线路发生单相接地故障而断路器单相跳闸瞬间,输电线路和高压电抗器处于缺相运行状态。如果高压电抗器匝间保护的电压采样取自母线TV二次侧,匝间保护在一次设备非全相运行时将会误判成区内故障而动作跳闸。文章根据一起330 kV线路单相瞬时性故障引起电抗器保护装置的匝间保护误动作、造成线路两侧断路器三相跳闸事件,分析了高压电抗器处于各种非正常情况下匝间保护动作原因,指出为防止电抗器非全相运行时匝间保护误动作应采取的措施。

Analysis on Reasons for Malfunction of Interturn Protection of 330 kV HV Reactor

The HV transmission line equipped with phase-splitting reactor in parallel and the HV reactor operate at open-phase while the transmission fails with one phase and the breaker trips with one phase. Provided that the voltage sampling for the interturn protection of the HV reactor is from the secondary side of the busbar TV, the interturn protection in malfunction judges it is the sectional failure and trips while the electric equipment operates in open phase. In this paper, reasons for the interturn protection when the HV reactor is at abnormal conditions are analyzed through the three-phase trips of the breakers on both sides resulted from the malfunction of the interturn protection of the reactor caused by the single-phase transient failure of 330 kV. It points out the measures to be taken to avoid the malfunction of the interturn protection while the reactor operates in open phase.