探讨解决穿越性大电流冲击导致主变重瓦斯保护误动作的方法

Discussion on the Method for Solving the Transformer Heavy Gas Protection False Action Caused by the Through Current Impingement

大容量变压器在区外接地故障或遭受雷击时,会产生穿越性大电流。穿越性大电流冲击主变压器时,会产生很大的电动力,从而引起主变压器线圈挤压和变形,主变压器油箱内绝缘油迅速向油枕方向流动,涌动的油流冲击瓦斯继电器挡板,使主变重瓦斯保护动作,跳开主变压器三侧开关,从而严重影响了变压器的稳定。防止瓦斯继电器在穿越性大电流下误动是变压器稳定运行的重要研究课题。通过分析穿越性大电流的产生、瓦斯继电器的动作原理,结合变电站的实际情况,发现在瓦斯继电器重动出口增加一个延时,可以躲过穿越性电流的切断时间,从而避免重瓦斯保护误动作。根据该结论,对某变压器瓦斯继电器回路进行了整改和试运行,使变压器的稳定性得到了较大提高。

When in the area of the ground fault or lightning strikes, large capacity transformer will produce a large cur- rent. When the through current impinges transformers, cause the transformer coil extrusion or even deformation. Then mak- ing the transformer insulating oil flow rapidly into the conservator. And surging oil flow lash the baffle of gas relay to make the transformer heavy gas protection act, eventually leading to the three sides switch tripping of the transformer. This seri- ously affects the stability of the transformer. How to prevent the gas relaying under the large current is the important re- search topic of the transformer stable operation. Analysis of the generation of the large current, the action principle of the gas relay, and actual situation of the transformer substation, are found in the gas relay to increase a delay, in order to escape through the cut off time, and can avoid the heavy gas protection. According to the conclusion, the circuit of the transformer gas relay is reformed and the trial operation is carried out, and the transformer stability has been greatly improved.