摘要
电流互感器(current transformer,CT)是变电站母线电流的核心量测设备,其二次回路出现多点接地问题时将导致母线保护装置误动作。对此,该文具体分析了CT二次回路多点接地时的电磁感应电流产生原理,并给出了相应的防范措施。在分析了三相CT电气连接以及单相的物理接线结构后,该文分别建立了CT正常运行和多点接地时的二次回路等效电路,然后详细推导了二次回路内电磁感应电流的计算过程,分析了影响感应电流大小的主要因素。紧接着,该文结合实际案例开展了感应电流与电磁感应强度的正反演计算,结果验证了所提二次回路感应电流计算方法的正确性。最后,该文给出了防范CT二次回路多点接地产生感应电流的措施,以提升CT运行安全性和稳定性。
The current transformer(CT)is the core measuring device of the busbar current in substations,the fault of multi-point grounding in its secondary circuit may lead to the misoperation of the busbar protection device.This paper specifically analyzes the generation principle of electromagnetic induction current when the secondary circuit of CT is grounded at multiple points,and provides corresponding preventive measures.After analyzing the electrical connections of three-phase CT and the physical wiring structure of a single phase of it,this paper establishes the equivalent circuits of the secondary circuit of the CT in normal operation and multi-point grounding status respectively.Then,the calculation process of electromagnetic induction current in the secondary circuit is derived in detail,and the main factors affecting the magnitude of induced current are analyzed.Subsequently,this paper conducts forward and backward calculations of induced current and electromagnetic induction intensity based on a practical case,and the results verified the correctness of the proposed method for calculating the induced current in secondary circuits.Finally,this paper provides corresponding measures to prevent the induction current generated by the multi-point grounding in the secondary circuit of CT to improve the safety and stability of CT operation.
作者
姜骞
毛先胤
李堃
杨旗
钟尧
JIANG Qian;MAO Xianyin;LI Kun;YANG Qi;ZHONG Yao(Electric Power Research Institute of Guizhou Power Grid Co.,Ltd.,Guiyang Guizhou 550002,China)
出处
《电力大数据》
2024年第11期91-100,共10页
Power Systems and Big Data
基金
贵州省科技计划项目(黔科合支撑〔2023〕一般291)。
关键词
电流互感器
二次回路
多点接地
电磁感应电流
保护误动
current transformer
secondary circuit
multi-point grounding
electromagnetic induction current
protection misoperation
作者简介
姜骞(1997),男,博士,助理工程师,主要从事输变电设备数字化与感应电防治相关工作。
