直流线路故障时抑制交流过电压的延时移相策略研究  

Study on delayed retard strategy to restrain AC overvoltage in DC line fault

作　　者：吕彦北 卢东斌[1] 李林[1] 龚飞 LU Yanbei;LU Dongbin;LI Lin;GONG Fei(NR Electric Co.,Ltd,Nanjing 211102)

机构地区：[1]南京南瑞继保电气有限公司,南京211102

出　　处：《电气技术》2023年第5期76-81,共6页Electrical Engineering

基　　金：国家电网公司总部科技项目(5100-202249004A-1-1-ZN)。

摘　　要：特高压直流输电系统中,当发生直流线路故障时,根据运行工况的不同,整流侧需要进行移相重启或移相闭锁。巴西美丽山双回直流送端同为欣古换流站,在美丽山二期直流移相重启或移相闭锁时欣古换流站交流电压迅速升高,可能引起美丽山一期直流受端及附近多回直流同时发生换相失败。为解决美丽山二期直流线路故障时整流侧移相重启或移相闭锁导致的交流过电压问题,提出直流线路故障延时移相策略,即在发生直流线路故障时延迟一段时间再进行移相重启或移相闭锁,移相前借助直流电流控制器来抑制直流故障电流。试验结果表明,采用延时移相策略后,欣古换流站过电压问题可以得到抑制,有助于降低美丽山一期直流系统发生换相失败的概率。该策略在巴西美丽山二期直流工程中应用后,现场发生直流线路故障后的动作结果与仿真结果一致,可在其他有类似过电压抑制需求的直流工程中进行推广应用。When DC line fault occurs in high voltage direct current(HVDC)transmission system,retard or block shall be carried out in rectifier according to different operating conditions.Two Bele Monte HVDCs share one rectifier converter station,Xingu converter station.When Bele Monte Ⅱ is carrying out retard or block,the AC voltage of Xingu converter station rises rapidly,which may cause commutation failure of Bele Monte Ⅰ and other HVDCs nearby.In order to solve the problem of AC overvoltage caused by retard or block of rectifier in DC line fault of Bele Monte Ⅱ HVDC,delayed retard strategy for DC line fault is proposed.That is to say,when DC line fault occurs,the retard or block is delayed for a period of time,before that the DC fault current is restrained by means of the DC current controller.The test results show that the AC overvoltage of Xingu converter station can be well restrained by adopting the delayed retard strategy,which is helpful to reduce the probability of commutation failure of Bele Monte Ⅰ HVDC.After the strategy is applied in Bele Monte Ⅱ HVDC,the action results after DC line fault on site are consistent with the simulation results.This strategy can be applied to other HVDC projects with similar overvoltage suppression requirements.

关 键 词：高压直流(HVDC) 直流线路故障 延时移相 过电压抑制 换相失败 

分 类 号：TM721.1[电气工程—电力系统及自动化] TM75