保护装置利用尖峰脉冲判别二次CT 断线的新方法  

A new method for distinguishing secondary CT disconnection by using spikes

作　　者：赵寿生 刘乃杰 赵志宏[2] 肖远清[2] ZHAO Shousheng;LIU Naijie;ZHAO Zhihong;XIAO Yuanqing(Jinhua Power Supply Company,State Grid Zhejiang Electric Power Co.,Ltd.,Jinhua 321001,China;Beijing Sifang Automation Co.,Ltd.,Beijing 100085,China)

机构地区：[1]国网浙江省电力有限公司金华供电公司,浙江金华321001 [2]北京四方继保自动化股份有限公司,北京100085

出　　处：《电力系统保护与控制》2020年第19期128-133,共6页Power System Protection and Control

基　　金：国家电网公司总部科技项目资助(SGBJDK00KJJS900088)。

摘　　要：现场发生一起保护屏二次CT断线导致过流保护动作的事故,在CT开路故障期间,发现保护录波报告的交流量中具有尖峰脉冲这一特殊的现象。分析认为,出现该现象的主要原因是由于在CT开路点处产生了很高的开路电压,造成开路点的瞬时击穿,导致保护装置采集到了高幅值的尖峰脉冲。若每周波持续出现一段时间的尖峰脉冲,会导致过流保护动作。模拟现场试验,再现了当时现场的故障情况,并得出以下结论:开路电压越高、CT开路间隙适当增大,越有可能出现尖峰脉冲,但以往的CT断线判据并不适用这一特征。提出了利用交流电流中的尖峰脉冲特征识别CT断线的新方法,作为保护装置原有CT断线判据的补充。An accident occurred in a scenario where a secondary CT disconnection of the protective screen caused overcurrent protection action.During the CT open circuit failure,a special phenomenon of spikes in the AC volume of the protected recording report is found.According to the analysis,the main reason for this phenomenon is that a high open circuit voltage is generated at the CT open circuit point,causing instantaneous breakdown of the open circuit point,and resulting in the protection device collecting a high amplitude spike.If the weekly wave continues to show a spike for a period of time,it will cause overcurrent protection.The simulated field test reproduces the fault condition at the scene and concludes that the higher the open circuit voltage and the more the CT open gap increases,the more likely the spike will occur.However,the previous CT disconnection criterion does not allow for this feature.This paper proposes a new method to identify CT disconnection using spike characteristics in AC current,and it is used as a supplement to the original CT disconnection criterion of the protection device.

关 键 词：保护装置 CT断线 电流互感器 开路电压 尖峰脉冲 

分 类 号：TM452[电气工程—电器]