电压互感器二次绕组中性点在开关场接地反措分析

Analysis on Anti-accident Measures of the Secondary Windings' Neutralpoint of the Voltage Transformer in Switch Yard

电压互感器二次绕组中性点在开关场经放电间隙或氧化锌阀片接地,目的是防止TV二次回路发生过电压。但运行中由于该接地设备击穿造成TV二次回路两点接地的情况时有发生,造成继电保护装置失去方向判断而发生不正确动作,原因是该条反措在执行时忽略了许多因素,包括没有统一的设计和产品制造标准、现场运行条件差使设备容易被击穿等,进而提出针对该条反措的应对措施,包括统一标准、加强地网结构或取消该条反措等。

The neutral-point of the voltage transformer＇s secondary winding is grounded through discharginggap or zinc oxide valve in switch yard,the purpose is to prevent the secondary circuit from being over-voltage. While the TV＇s secondary circuit is always grounded through two points during the process of operation,because of the punctured grounding equipment,it makes the relay protection equipments taking falseactions for losing judgment of direction. The reason is that it ignored many factors when being carried out,including there is no unified standards of designing and manufacture standard, poor operational conditions.And then it proposes some methods related to this anti-accident measures,which includes unifying the stan？dards,strengthening the structure of grounding net,and canceling this measures,etc.