直流输电换流变故障分析及保护改进  

Fault Analysis and Protection Improvement of HVDC Converter Transformer

作　　者：郑超[1,2] 张晓宇 吕航[1,2] 孙浩晖 

机构地区：[1]南京南瑞继保电气有限公司,江苏南京211102 [2]南瑞集团有限公司(国网电力科学研究院有限公司),江苏南京211106 [3]华北水利水电大学电力学院,河南郑州450045

出　　处：《工业控制计算机》2020年第1期118-121,共4页Industrial Control Computer

摘　　要：直流输电工程中,换流变保护区内阀侧发生单相接地故障时,存在保护灵敏度低、可靠性差的问题。分析了换流变阀侧故障的故障特征,对比换流变与传统交流变压器的运行工况的差异,结合波形分析结果,验证了基于差分滤波、工频基波有效值的差动保护计算方法不适用于换流变保护,提出取消差分滤波并采用全波电流有效值计算差动保护的改进措施,利用实际的特高压直流工程仿真系统进行验证,结果证实改进后的差动保护解决了阀侧单相接地故障灵敏度低、可靠性差的问题。In DC transmission engineering projects,when a valve-side single-phase ground fault occurs,the protection has problems of low sensitivity and poor reliability.This paper analyzes the fault characteristics of the valve side fault of the converter transformer,and compares the operating conditions of converter and traditional AC transformer,combining with the waveform analysis results,it is verified that the differential protection calculation method based on differential filter and RMS of power frequency fundamental wave is not suitable for converter protection,and propose the improvement measures of canceling differential filter and using full-wave current RMS to calculate differential protection,which verified by the actual UHVDC project simulation system,the results show that the improved differential protection solves the problem of low sensitivity and poor reliability of the single-phase ground fault on the valve side.

关 键 词：换流变保护 阀侧故障 差分滤波 全波电流有效值 灵敏度 可靠性 

分 类 号：TM721.1[电气工程—电力系统及自动化]