乒乓式转子接地保护两点接地的误判和解决办法  

The Way to Solve the Fault of Ping-pong Type Protection in Two Points Groudfault

作　　者：徐健[1] 王翔[1] 

机构地区：[1]南瑞继保电气有限公司,江苏省南京市211100

出　　处：《电网技术》2006年第S2期459-462,共4页Power System Technology

摘　　要：鉴于乒乓式的转子接地保护有很多优点,现在的发电机保护的转子接地保护很多是采用的这个原理。这种采用开关切换来列方程求解接地电阻大小和接地位置的原理在表现出很大优点的同时也存在着一些缺点,当发生转子一点接地以后,接地电阻的大小发生变化可能会引起两点接地保护的误判。设真正动作和误判两种情况下保护装置算得的第二点接地电阻的大小相同,可以通过比较真正两点接地故障和由于接地电阻突变导致误判的情况下从转子负端流进接地电阻的电流来确定是不是发生真正的两点接地故障,这两种情况下从转子负端流进接地电阻的电流大小是不一样的。可以利用这种区别来判断是发生了真的两点接地故障还是由于接地电阻突变而造成的两点接地故障的误判,这样可以消除乒乓切换原理实现转子接地保护所固有的缺点。Ping-Pong Type Protection for Ground Fault is very popular as it is a good protection, but it still has some faults. When a one point Ground Fault has happened, it will be remembered, the protection equipment will wait for that whether the two points Ground Fault happen later. If the resistance of the one point Ground Fault is changing, this protection may make a wrong judgment to tell that a two points Ground Fault is happening. Using the changing of current flowing through the Rotor to judge whether a true two points Ground Fault is happening . This way can improve the Ping-Pong Type Protection to be a better protection.

关 键 词：乒乓式保护 一点接地 两点接地 

分 类 号：TM862[电气工程—高电压与绝缘技术]