10kV线路故障导致主变保护误动分析

Analysis of Main Transformer Protection Malfunction Caused by 10 kV Line Fault

针对一例10 kV线路相间故障导致110 kV主变差动速断保护误动的事件,从故障录波波形上分析了主变差动速断保护两侧CT在暂态饱和情况下区外故障误动的原因,并从如何防止CT暂态饱和及主变保护装置饱和判据方面提出解决措施。

In view of the event that an interphase fault of the 10 kV line leads to the malfunction of the 110 kV main transformer's differential protection,the paper analyzes the reasons of the main transformer*s differential speed protection malfunction when the fault is outside the protected area and the current transformers on both sides are in transient saturation.And the solution measures of prevent CT transient saturation and the saturation criterion of the main transformer protection device are put forward.