无外界负荷新建站的主变保护相量检查新方法

The New Phasor-check Method of Transformer Protection in New 220 kV Substation Without the Outside Load

许多新建220 kV变电站在投入运行时其三绕组变压器中、低压侧尚无外界负荷,只在低压侧有用于无功补偿的电容器负荷,中压侧没有负荷可供相量检查。为此,文章提出了利用站内负荷通过运行方式的变换完成两台主变三侧电流回路相量检查的新方法,并以唐山地区古马220 kV变电站为例介绍了具体操作步骤和相量检查结果。理论分析和实践表明,该方法简便易行、结果可靠,有效地解决了中压侧没有负荷进行相量检查的问题。建议无外界负荷新建站启动时,推广利用站内负荷一次性完成主变三侧相量检查的方法,以减少主变保护退出运行的时间,保证电网的安全稳定运行。

During the commission of many new 220 kV substations,the three-winding transformers do not have the outside load on the medium and low voltage side.There are only some capacitors that are used for reactive power compensation,and there is no load for the phasor-check on the medium voltage side.Therefore,this paper proposes the phasor-check method of transformer protection,which only uses the inside load by the change of the operation modes.Based on 220 kV Guma substation,the concrete operation step and the result of the phasor-check is presented.The theoretical analysis and practice show that the method is simple,feasible and reliable,thus effectively solved the difficult problems that there is no load on the medium voltage side during the phasor-check.So this new method is recommended to be gradually used when the new substation without the outside load is commissioning,for reducing time when the transformer protection is withdrawn from running and ensuring power system in safe and stable operation.