基于直流电流动态上升的高压直流输电系统换相失败分析  

Commutation failure analysis in HVDC transmission system based on DC current dynamic rise

作　　者：苏常胜[1,2] 尹纯亚 李凤婷 SU Changsheng;YIN Chunya;LI Fengting(School of Electrical Engineering,Xinjiang University,Urumqi 830046,China;State Grid Xinjiang Electric Power Co.,Ltd.,Urumqi 830036,China)

机构地区：[1]新疆大学电气工程学院,新疆乌鲁木齐830046 [2]国网新疆电力有限公司,新疆乌鲁木齐830036

出　　处：《电力自动化设备》2023年第3期204-209,共6页Electric Power Automation Equipment

基　　金：国家自然科学基金资助项目(51877185);新疆维吾尔自治区青年科学基金资助项目(2022D01C85)。

摘　　要：针对现有换相失败分析方法未考虑交流系统故障后直流电流动态上升对关断角影响的问题,在分析直流电流变化对关断角影响的基础上,首先推导了对称故障下未考虑直流电流变化以及考虑直流电流瞬时变化的换相失败分析方法。分析结果表明,当逆变侧换流母线电压跌落在一定区间内,以上2种方法会导致换相失败判别结果不准确。为此考虑交流系统故障后直流线路和直流控制的动态过程,推导了直流电流的时域表达式,通过求解直流电流最大值,提出了一种考虑直流电流动态上升的换相失败分析方法。最后基于PSCAD/EMTDC仿真平台验证了所提方法的有效性以及对高压直流输电系统换相失败判别结果的正确性。Aiming at the problem that the existing commutation failure analysis methods do not consider the impact of the dynamic rise of DC current on the extinction angle after AC system faults,on the basis of analyzing the influence of DC current variation on the extinction angle,a commutation failure analysis method is firstly deduced which considers whether DC current instantaneous rise or not under symmetric fault. The analysis results show that it is possible for the commutation failure results to be misjudged when the voltage of converter bus at inverter side fall within a certain range. Therefore,considering the dynamic process of a DC line and the DC control after AC system fault,the time domain expression of DC current is derived. By solving for the maximum value of DC current,a commutation failure analysis method considering DC current dynamic rise is proposed. Finally,based on PSCAD/EMTDC simulation platform,the validity of the proposed method and its correctness on the commutation failure discrimination results are verified.

关 键 词：高压直流输电系统 换相失败 直流电流 关断角 判别方法 

分 类 号：TM721.1[电气工程—电力系统及自动化]