A Weighted Voltage Droop Control for Reducing DC Voltage Deviation

摘要

DC voltages in the voltage-source converters based multi-terminal HVDC (VSC-MTDC) grid will experience fluctuations under various disturbances, especially a VSC outage. Based on the translations of the power-voltage (P-V) curve of the conventional voltage droop (CVD) control, this paper proposes a new weighted voltage droop (WVD) control to reduce DC voltage deviations. The weighted voltage is introduced as the key indicator for the proposed control and the steady voltage deviations are reduced significantly without changing the steady active power distribution. A MTDC grid with four-terminal VSCs is established in the PSCAD/EMTC software for the case study. Various severe fault conditions are taken account in the case study, including the outage of a constant power VSC and the outage of a droop VSC. Simulation results have illustrated the effectiveness and superiority of the proposed weighted voltage droop (WVD) control.