330kV变电站中刀闸接触不良对断路器保护的影响

The Influence of Poor Knife-switch Contact on Circuit Break Protection at the 330 kV Substation

以某330 kV变电站发生的刀闸接触不良缺陷为例,对此类缺陷是否会对保护装置的正常运行产生影响进行了分析,得出了在刀闸接触不良时断路器失灵保护及断路器死区保护不能正确动作,进而可能导致事故扩大的结论。为了避免此类问题,提出了在断路器保护中增加"低负荷TA断线告警"信号的方法,从而使调控中心监控员在线路低负荷运行时可以及时发现刀闸接触不良的缺陷,避免在发生故障时断路器失灵保护及断路器死区保护不能正确动作的事故发生。

Taking the defect of poor contact of the knife-switch at a 330kV substation as an example, this paper analyzes the possibility of affection of＇ such defects upon normal operation of the protective device. It is so concluded that in the case of poor contact of the knife- switch, the malfunction protection and dead zone protection of the breaker cannot operate correctly, thus resulting in the expansion of the accident. To avoid this problem, this paper proposes that a ＂ low load TA disconnection alarm＂ signal should be added to the breaker protection so that the control center monitor may timely discover the defect of poor contact of the knife-switch when the line is operated under a low load to avoid accidents where the malfunction and dead zone protection of the breaker cannot operate correctly in case of failure.