Abstract: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.
吕彦北, 卢东斌, 李林, 龚飞. 直流线路故障时抑制交流过电压的延时移相策略研究[J]. 电气技术, 2023, 24(5): 76-81.
LÜ Yanbei, LU Dongbin, LI Lin, GONG Fei. Study on delayed retard strategy to restrain AC overvoltage in DC line fault. Electrical Engineering, 2023, 24(5): 76-81.