Abstract：The receiving side of Qingyu HVDC is hierarchically connected to two 500kV AC grid, which has spilt and closed loop opera-tion modes. HVDC system needs to be compatible with hierarchical and non-hierarchical control modes. This paper intro-duced AC/DC power grid structure characteristics of Qingyu HVDC, analyzed the influence of DC midpoint voltage divider fault on HVDC and the shortage of existing coping strategies. Then, the entry & exit strategy of midpoint voltage divider which can adapt to the structure characteristics of Qingyu HVDC is proposed. At the same time, the risk of HVDC operation caused by long-term use of calculated value of control system after mid-point voltage divider fault is avoided. It also solves the problem of long-time block of the converter after non-electric protection action of midpoint voltage divider, and improves the available rate of HVDC operation.
刘凯, 邹强, 张庆武, 肖建民, 刘孝辉. 青豫直流受端中点分压器投退策略研究[J]. 电气技术, 2021, 22(4): 20-25.
LIU Kai, ZOU Qiang, ZHANG Qingwu, XIAO Jianmin, LIU Xiaohui. Research on entry and exit strategy of midpoint voltage divider in receiving side of Qingyu HVDC. Electrical Engineering, 2021, 22(4): 20-25.
2021, Vol. 22 
