Study on the Effect of Multi-Type Current Transformers Hybrid Operation on Differential Protection of the Bus Based on Dynamic Simulation

This paper analyzes characteristics of multi type current transformers hybrid operation for each branch of the bus and their effects on differential protection of the bus. By theoretically analyzing transmission characteristics of multi type current transformers and their influence factors, we study the dynamic model testing method of multi type current transformers for the bus, and design 3 kinds of testing schemes by making the equivalent model based on the field of P-level current transformer, TPY-level current transformer and electronic current transformer, and build the hybrid operation testing platform of multi type current transformers. Finally, we compare and analyze the transmission characteristics difference of multi type current transformers on the same branch and the characteristics difference of hybrid operation in two successive external faults, analyze the cause behind the differences, and put forward the corresponding improvement measures.

多类型电流互感器混联运行动模测试平台建设及对差动保护的影响

分析线路两侧的多类型电流互感器混联运行特性,理论推导混联运行的差流表达式,并分析其影响因素。在此基础上,研究多类型电流互感器混联运行动模测试方法,设计6种测试方案,制作与实际电流互感器等效的P级电流互感器、TPY级电流互感器及电子式电流互感器模型,并搭建混联运行动模测试平台。基于以上测试平台,对多类型电流互感器的传递性能差异对比测试,通过连续两次区外故障时混联运行的比率制动特性及动作轨迹,分析混联运行对差动保护的影响,提出相应的改进措施。