一起500 kV主变零差保护误动原因分析及预防措施

详细分析了一起500 kV主变零差保护因零差平衡系数设置错误,在区外的一条500 kV AG线路故障导致某站主变零差保护误动跳三侧开关的原因,阐述了500 kV主变零差保护CT配置及动作方程,有针对性地提出了防止零差保护设置零差平衡系数造成误动的措施,对基层供电局继电保护现场工作人员有借鉴意义,有助于提高电网的安全可靠运行。

Analysis of a 500 kV transformer zero-sequence differential protection fault and its prevention

This paper analyzes a 500 kV transformer zero-sequence differential protection fault resulted from three-side breakers trip when fault site was out of the reply prevention zone.That balanced coefficient was set defaultly is considered as the main cause of that accident.The paper represents the configuration and action equation of the 500kV transformer zero-sequence differential protection,and puts forward the way which can prevent the faults caused by the configuration of zero balancing coefficient.The way can be adopted by the relay protection personal on site,and is contributed to the safety and reliability of the power system.