受端不对称故障引发LCC-HVDC换相失败时送端暂态过电压特性分析  

Characterization of Transient Overvoltage of Sending-end AC System When Commutation Failure Caused by Asymmetrical Fault

作　　者：韩梓畅 王彤 王潇桐 王增平 赵伟 HAN Zichang;WANG Tong;WANG Xiaotong;WANG Zengping;ZHAO Wei(State Key Laboratory of Alternate Electrical Power System With Renewable Energy Sources(North China Electric Power University),Changping District,Beijing 102206,China;North China Branch of State Grid Corporation of China,Xicheng District,Beijing 100053,China)

机构地区：[1]新能源电力系统全国重点实验室(华北电力大学),北京市昌平区102206 [2]国家电网有限公司华北分部,北京市西城区100053

出　　处：《电网技术》2025年第4期1532-1540,I0059,共10页Power System Technology

基　　金：国家电网总部科技项目(5108-202218280A-2-267-XG)。

摘　　要：传统高压直流系统在逆变侧发生换相失败时,整流器无功消耗的大量减少将导致送端产生严重的过电压。逆变侧不同故障类型引发的换相失败将对整流器的无功特性产生重要影响。该文从理论上分析了不同类型的不对称故障引发换相失败时整流侧暂态过电压的动态过程。首先,通过分析不对称故障后12脉动换流器相邻两换相线电压的角度差,揭示了单相接地故障、两相短路故障和两相接地故障直流关断角的周期性波动规律。其次,详细分析了不对称故障导致换相失败时整流器的暂态无功功率特性,发现不对称故障导致直流系统周期性提前进入定电流控制,最终导致暂态过电压峰值呈现周期性时间分布特征。不对称故障导致的暂态过电压峰值周期性大于三相对称故障导致的暂态过电压峰值,其中单相接地故障导致的暂态过电压峰值出现在1/4和3/4工频周期处,两相相间故障或两相接地故障导致的暂态过电压峰值出现在1/2和1工频周期处。最后,基于PSCAD平台的CIGRE-HVDC基准模型,通过仿真验证了该文内容的正确性,有效指导了系统运行中过电压预测的制定。This paper theoretically analyzes the dynamic process of the transient overvoltage on the rectifier ac system when commutation failure is triggered by different types of asymmetrical faults.Firstly,by analyzing the angular difference between two neighboring commutated-phase line voltages of the 12-pulsation rectifier after asymmetrical fault,the periodic fluctuation law of DC turn-off angle of single-phase grounding fault,two phase short circuit fault and two-phase grounding fault are proposed.Secondly,the transient reactive power characteristics of the rectifier during commutation failure due to asymmetrical fault are analyzed in detail,revealing that the asymmetrical fault causes the DC system to periodically enter the constant current control in advance,which ultimately results in the peak transient overvoltage showing a periodic time distribution characteristic.The peak transient overvoltage due to the single-phase grounding fault is obtained to be present at 1/4 and 3/4 cycle,and the peak transient overvoltage due to the two-phase inter-phase failure or the two phase grounding fault is obtained to be present at the 1/2 and 1 cycle.Finally,based on the PSCAD platform’s CIGRE-HVDC benchmark model,the correctness of the content of this paper is verified by simulation,which effectively guides the formulation of overvoltage anticipation in system operation.

关 键 词：暂态过电压 不对称故障 高压直流输电 周期性时间分布规律 

分 类 号：TM721[电气工程—电力系统及自动化]