110 kV主变差动保护误动原因分析

Analysis of Misoperation Cause of 110 kV Main Transformer Differential Protection

110 kV变电站低压侧一回出线发生三相短路故障,线路保护和重合闸依据整定运行规则正确可靠动作,但在重合闸重合于永久性故障且线路保护正确动作切除故障的情况下,主变差动保护误动,造成上网功率减小。

Three-phase short-circuit fault occurred in the low-voltage side primary line of 110 kV substation,and the line protection and reclosing acted correctly and reliably according to the setting operation rules.However,when reclosing was coincident with permanent fault and the line protection acted correctly to remove the fault,the main transformer differential protection misoperated,resulting in reduced online power.