抑制直流偏磁导致的互感器饱和的直流补偿法  

Direct Current Compensation of the Current Transformer Transient Saturation Caused by Direct Current Bias Suppression

作　　者：李江峡 黄景光[1] 张宇鹏 林湘宁[2] 郑钦杰 LI Jiang-xia;HUANG Jing-guang;ZHANG Yu-peng;LIN Xiang-ning;ZHENG Qin-jie(Hubei Provincial Key Laboratory for Operation and Control of Cascaded Hydropower Station,China Three Gorges University,Yichang 443002,China;State Key Laboratory of Advanced Electromagnetic Engineering and Technology,Huazhong University of Science and Technology,Wuhan 430074,China)

机构地区：[1]三峡大学梯级水电站运行与控制湖北省重点实验室,宜昌443002 [2]华中科技大学强电磁工程与新技术国家重点实验室,武汉430074

出　　处：《科学技术与工程》2021年第9期3618-3625,共8页Science Technology and Engineering

基　　金：国家自然科学基金(51477090)。

摘　　要：在超特高压直流输电线路相继投入运行的背景下,直流偏磁造成电流互感器(current transformer, CT)饱和的现象日趋严重,抑制CT饱和尤为重要。通过直流偏磁产生机理和CT等效模型的建立,推导得到3种CT暂态饱和时的二次电流及铁芯磁链表达式,并提出直流补偿法来抑制直流偏磁导致的CT暂态饱和。基于电力系统计算机辅助设计PSCAD(power systems computer aided design)仿真平台,分析直流偏磁对CT二次电流的影响,通过定量计算得到补偿直流与偏磁电流的对应关系。抑制电流互感器暂态饱和可以确保其准确地将一次电流传变至二次侧,二次电流波形不会出现畸变,能够避免因差流过大引起的保护误动,确保电力系统安全可靠运行。此外,针对励磁涌流及接地故障造成的CT饱和,仿真结果验证该方法切实可行。Under the operation of ultra-high voltage direct current(DC)transmission line,the current transformer(CT)saturation caused by DC bias is becoming more and more serious,and it is urgent to suppress CT saturation.In this research,through the establishment of DC bias generation mechanism and CT equivalent model,the secondary current and iron core magnetic chain expressions of three CT transient saturations were derived,and the CT transient saturation caused by DC bias was suppressed based on DC compensation method.Based on the power systems computer aided design(PSCAD)simulation platform,the influence of DC bias on CT secondary current was analyzed,and the correspondence between DC and bias current was compensated by quantitative calculation.The suppress of the transient saturation of the current transformer could ensure that it accurately changed the current flow to the secondary side,thus the secondary current waveform would not be distorted.It could avoid the protection error caused by the excessive current difference,and ensure the safe and reliable operation of the power system.In addition,for CT saturation caused by excitation surge and ground fault,the simulation results verified the feasibility of the method.

关 键 词：直流偏磁 电流互感器 暂态饱和 直流补偿 

分 类 号：TM452.8[电气工程—电器]