Research on power flow calculation method of true bipolar VSC-HVDC grids with different operation modes and control strategies
Botong Li, Botong Li, Wenxin Wang, Yichao Liu, Bin Li, Bin Li, Weijie Wen
Abstract
Compared with the pseudo bipolar Voltage Source Converter (VSC) based High Voltage Direct Current (HVDC) (VSC-HVDC) grid, the true bipolar VSC-HVDC grid with series voltage source converters is more flexible and reliable. Based on the analysis of structure and power distribution in the true bipolar VSC-HVDC grid, the node admittance matrices and a representation method of the converter station losses are first derived. Then, with various station-level control strategies of VSC taken into account, a layer-based power flow calculation method suitable for true bipolar VSC-HVDC grids in both symmetric and asymmetric operation is proposed. Finally, the applicability and accuracy of the proposed power flow calculation method are verified by a true bipolar VSC-HVDC grid model built in PSCAD.