非同期合闸对发电机-变压器组差动保护的影响及解决措施

Impact of Non-synchronization Closing to Generator-transformer Unit Differential Protection and the Solutions

通过对2例差动保护误动案例的分析,得出实际电厂非同期合闸引起的发变组保护误动和厂用电快切过程中引起的启备变、厂高变保护的误动,并非是由于在同期合闸过程中变压器的电压发生了较大变化而产生非同期合闸涌流,而是非同期合闸电流中的非周期分量导致两侧电流互感器饱和而引起差动保护误动,并提出了相应的解决措施。

This paper analyzes two mal-operation examples of actual power plants differential protection. It draws a conclusion that the reason of mal-operation by non-synchronization closing and mal-operation by power consumption of auxiliaries quicktripping, is not the non-synchronization closing inrush current caused by the transformer voltage changing more during synchronization closing, but the current transformer saturation caused by the non-periodic component of non-synchronization closing current. Some solutions are proposed also.