母线差动保护电流互感器断线处理逻辑  

Processing Logic Against Current Transformer Disconnection of Busbar Differential Protection

作　　者：王风光[1,2] 杜兴伟 李力 吕航[1,2] 丁杰 WANG Fengguang;DU Xingwei;LI Li;LYU Hang;DING Jie(NR Electric Co.,Ltd.,Nanjing 211102,China;State Key Laboratory of Smart Grid Protection and Control,Nanjing 211106,China;State Grid Henan Electric Power Co.,Ltd.,Zhengzhou 450018,China)

机构地区：[1]南京南瑞继保电气有限公司,江苏省南京市211102 [2]智能电网保护和运行控制国家重点实验室,江苏省南京市211106 [3]国网河南省电力公司,河南省郑州市450018

出　　处：《电力系统自动化》2023年第14期167-173,共7页Automation of Electric Power Systems

基　　金：国家重点研发计划资助项目(2021YFB2401004)。

摘　　要：根据电流互感器(CT)断线对于母线差动保护的影响程度,分为支路CT断线和母联CT断线。首先,介绍了当前母线差动保护对于CT断线的处理逻辑,指出了当前逻辑存在的准确性不高、快速性不足的问题。然后,分析了母线接地故障与CT断线特征的差异,提出了包含故障识别逻辑、CT断线支路选线逻辑和故障后跳闸逻辑3个部分的支路CT断线改进处理逻辑,并引入母联双CT电流构建母联死区差动元件,提出了综合利用大差差动电流、小差差动电流和母联死区差动电流的母联CT断线的改进处理逻辑。最后,基于实时数字仿真系统试验结果,证明了改进后的逻辑能够快速准确地选择断线CT,避免差动保护在重负荷支路CT断线时误动和母线区内高阻接地故障时拒动,在发生母联CT断线时最大限度地维持了差动保护的速动性。According to the influencial degree of current transformer(CT)disconnection on the busbar differential protection,it can be divided into feeder CT disconnection and bus coupler CT disconnection.First,the processing logic of the current busbar differential protection for CT disconnection is introduced,and the problems of low accuracy and insufficient speed of the current logic are pointed out.Then,the differences between the busbar grounding fault and the CT disconnection characteristic are analyzed.The improved processing logic of feeder CT disconnection is proposed,which includes fault identification logic,selection logic of feeder CT disconnection and trip logic after the fault.By introducing double CT current of bus coupler to construct the dead-zone differential component,the improved processing logic of bus coupler CT disconnection is proposed by comprehensive use of check-zone differential current,bus-zone differential current and dead-zone differential current.Finally,test results of real time digital simulation system show that the improved logic can quickly and accurately select the CT disconnection,avoid the differential protection maloperation in CT disconnection with heavy-load feeder and internal high-resistance grounding fault of busbar,which maintains the rapid performance of the differential protection when the bus coupler CT disconnection occurs.

关 键 词：差动保护 电流互感器(CT)断线 死区差动元件 高阻接地故障 

分 类 号：TM773[电气工程—电力系统及自动化] TM452