考虑时空离散性的高压直流输电系统换相失败评估方法  

A Method to Assess Commutation Failure of HVDC Systems Taking Space-Time Discreteness into Consideration

作　　者：蔡泽祥[1] 杨欢欢[1] 余超耘 李晓华[1] CAI Ze-xiang YANG Huan-huan YU Chao-yun LI Xiao-hua(School of Electric Power, South China University of Technology, Guangzhou 510640, Guangdong, China)

机构地区：[1]华南理工大学电力学院,广东广州510640

出　　处：《华南理工大学学报（自然科学版）》2017年第7期33-40,共8页Journal of South China University of Technology(Natural Science Edition)

基　　金：国家自然科学基金资助项目(51377059)~~

摘　　要：直流输电系统换相失败的特性随交流故障合闸角和故障位置的不同而不同,目前只考虑换流母线电压幅值跌落的直流系统换相失败判别方法准确性不高.文中研究了换相失败的时空离散性,分析了故障合闸角对换相失败的影响过程,指出最不利于换相的故障时刻,并且揭示了故障位置对换相失败的影响主要源于故障点与直流逆变母线之间电气距离和相位的差异.基于对换相失败时空离散性的分析,提出了同时计及电压幅值与相位变化的熄弧角判据和以此为基础的换相失败评估方法.以南方电网三节点AC/DC系统为背景,通过与PSCAD/EMTDC、BPA仿真结果的对比验证了该评估方法的有效性和实用性.As the characteristics of commutation failure of high-voltage direct current （ HVDC ） systems vary with not only fault close angle but also fault positions, the existing assessment methods that only consider the influence of voltage dip of converter bus are not accurate enough. In order to solve this problem, firstly, the space-time dis-creteness of commutation failure is investigated. Secondly, the influence of fault close angle on the process of com-mutation failure is analyzed, and the most unfavorable angle is pointed out. Then, two main causes for the impact of fault position on commutation fai lu re, namely the electrical distance and the phase difference between fault bus and DC inverter b u s, are discovered. Moreover, in light of the analytical results of space-time discreteness under the condition of commutation failure, a criterion of extinction angle, which takes both voltage amplitude and phase distortion into consideration, is proposed. Th u s , a method to assess commutation failure is presented. Finally, a comparison of the proposed method is made with PSCAD/EMTDC and BPA on a three-node AC/DC system in Chi-na Southern Power Grid. The results show that the proposed method is effective and practicable.

关 键 词：高压直流输电 换相 时空离散性 电压幅值 相位变化 總狐角 评估方法 

分 类 号：TM711[电气工程—电力系统及自动化]