基于欧氏距离法的换流变压器短路电流和励磁涌流的辨识  

Discrimination of Magnetizing Inrush and Short Circuit Current of Converter Transformer Based on Euclidean Distance

作　　者：邓艳平[1] 杨秀[1] 张美霞[1] 潘爱强[2] 

机构地区：[1]上海电力学院电气工程学院,上海市杨浦区200090 [2]国网上海市电力公司电力科学研究院,上海市虹口区200437

出　　处：《电网技术》2015年第9期2671-2676,共6页Power System Technology

基　　金：国家自然科学基金项目(71203137);国家电网公司科技项目(H2013-042)~~

摘　　要：在高压直流(high-voltage direct current,HVDC)输电系统中,换流变压器受各种交直流滤波器影响,发生不对称故障时,差动电流中2次谐波含量比较大。通过仿真分析可知,采用2次谐波制动时,某些故障情况下保护会发生拒动。经分析,励磁涌流波形具有间断和偏向时间轴一侧的特征,而故障时的差动电流在不计直流分量影响的情况下,其波形分布时间轴两侧且无间断角。据此,提出利用变压器二次出口采样电流与标准正弦曲线之间的欧氏距离来鉴别励磁涌流和故障电流。通过EMTDC进行了大量的仿真实验,验证了该判据的稳定性和有效性。Due to impacts of the filters in AC and DC fields in HVDC systems, the differential current contains large amount of 2nd order harmonic, the differential protection of the converter transformer may fail to trip in case of asymmetric internal faults. The simulation results prove that the 2nd order harmonic restraint criterion is not sufficient when applied to differential protection for converter transformer. As the magnetizing inrush contains dead angle and bias in one side of the time axis while the fault current is nearly sinusoid, a new method by measuring the Euclidean distance of sampling current of transformer and sine curve is proposed to discriminate the magnetizing inrush and the fault current of converter transformer. Stability and validity of the proposed criterion are verified with numerous simulation tests based on EMTDC.

关 键 词：换流变压器 差动保护 励磁涌流 2次谐波 

分 类 号：TM72[电气工程—电力系统及自动化]