A P-Q Coordination Control Strategy of VSC-HVDC and BESS for LVRT Recovery Performance Enhancement

Abstract

Voltage source converter (VSC)-based multi-terminal direct current (MTDC) transmission technology has been a research focus, and the low-voltage ride-through (LVRT) and recovery in receiving-end systems is one of the major problems to consider. A coordinated control strategy for a VSC-MTDC system is proposed to improve the frequency and voltage dynamics in the receiving-end system during the LVRT and recovery processes. A battery energy storage system (BESS) plays a significant role in providing frequency and voltage support with its flexible power control capability. During the LVRT process, the BESS can provide reactive current injection and active current absorption to improve system stability in the AC side, and during the recovery process, an adaptive current limitation method is proposed for the BESS converter to dynamically adjust the active and reactive power outputs according to the frequency and voltage deviation severity. Meanwhile, the coordination of the sending-end systems and DC chopper can reduce the power output to avoid DC overvoltage during LVRT, and it can also provide frequency support to the receiving-end system with the DC voltage transmitting frequency information during the recovery process. A simulation was carried out on the MATLAB/Simulink platform, and a three-terminal VSC-MTDC system was used to validate the effectiveness of the proposed strategy.