直流线路永久性接地故障环流抑制优化方案

Optimized circulating current suppression scheme for permanent DC line grounding fault

针对双极双十二脉动特高压直流线路永久性接地故障异常环流无法有效隔离问题,提出了故障异常环流抑制优化方案。首先分析直流线路永久性接地故障异常环流值的影响因素;其次结合国内直流线路故障清除现有策略,分析有通信工况下线路接地故障重启高端阀组异常环流、有通信工况及无通信工况下线路接地故障重启不成功闭锁异常环流的形成原因;然后据此提出基于极隔离以及移相90°再闭锁策略优化的直流线路永久性接地故障环流抑制方案;最后通过实时仿真系统(real time digital system,RTDS)建立仿真模型验证改进方案的有效性。结果表明,文中所提出的方案可有效解决不同工况下直流线路永久性接地故障异常环流问题。

For the problem that the abnormal circulation of bipolar double twelve-pulse ultra high voltage direct current(UHVDC)line permanent grounding fault can not be effectively isolated,an optimized scheme for suppressing the abnormal fault circulation is proposed.Firstly,the influencing factors of abnormal circulating current value for DC line permanent grounding fault are analyzed.Secondly,combined with the existing removal strategies of DC line fault in China,the causes of abnormal circulation are analyzed,which are caused by restarting the high-end valve group with communication condition,unsuccessful restart with communication condition or without communication condition after DC line grounding fault happens.Then,a circulating current suppression scheme for DC line permanent ground fault based on pole isolation and blocking after shifting phase 90°strategy is proposed accordingly.Finally,the simulation model is established through real time digital system(RTDS)to verify the effectiveness of the improved scheme.The results show that the scheme proposed in this paper can effectively solve the abnormal circulation problem of DC line permanent grounding fault under different working conditions.