Coordinated power control strategy of voltage source converter‐based multiterminal high‐voltage direct current based on the voltage‐current curve

Abstract

To achieve power distribution quickly and improve the anti‐interference capability of the voltage source converter‐based multiterminal high‐voltage direct current (VSC‐MTDC) system, a coordinated control strategy based on the V‐I curve is proposed in this article. The proposed control strategy includes the conventional droop control, the improved droop control, which considers the voltage dead band and fixed dc voltage control. The conventional droop control is utilized in one of the multiple converter stations, the fixed dc voltage control is adopted in the other one, and the improved droop control is applied to all of the rest converter stations. In this way, the unbalanced power will be distributed rapidly only through the conventional droop control, when the change of dc voltage is within the dead band. Meanwhile, all the droop coefficients of the improved droop control are adjusted automatically following the changes in dc current and dc voltage, and the converter stations regulate the unbalanced power coordinately, when the dc voltage is changed beyond the dead band. A model of a four‐terminal voltage source converter‐based high‐voltage direct current (VSC‐HVDC) transmission system is built in PSCAD/EMTDC, and the simulation results are presented to validate the expected performance of the proposed control strategy. © 2019 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.