系统负相序对变压器差动保护的影响

The influence of negative phase sequence system to differential protection for main transformer

根据应县魏庄变一次系统为负相序的具体实例,利用向量图分析法,深入详细地分析了国内变压器微机保护在一次正相序系统和一次负相序系统中应用时各侧电流的相位关系,并进行了比较,指出只要按变压器本身的接线组别,各侧绕组和CT的二次实际接线方式设置相应控制字,变压器微机差动保护就能正确运行。并提出具体应对措施,对现场工作具有现实指导价值。

The phase relation among side electric currents of internal transformer microcoputer peotection in the primary positive phase sequence system is different from those in the primary negative phase sequence system, this difference was analyzed thoroughly and detailedly by vector diagram, according to the instance of negative phase squence primary system in Weizhuang station,Yinxian county, the analyzing result indicates that the transformer microcoputer differential peotection runs normally if every side coil winding and secondary wiring pattern establish control word corresponding to the wiring group of transformer, and exact methods solving the problem are carried out, these practically valuable methods may improve on-site jobs.