Impact of DC control strategies on dynamic behaviour of multi-terminal voltage-source converter-based HVDC after sudden disconnection of a converter station

Multi-terminal HVDC (MTDC) transmission system using Voltage Source Converter (VSC) provides an increased transmission network capacity and generally enhanced system reliability, security and controllability. The aim of this paper is to evaluate the impact of dc-voltage control strategies on dynamic behaviour of MTDC VSC-Based HVDC after the sudden disconnection of a converter station. Two dc voltage control methods are considered in this paper: (i) voltage margin method and (ii) standard voltage-droop method. The impact is evaluated using time-domain simulations on simple test system using. The sudden disconnection of a converter-station is used as disturbance. Simulation results demonstrate there is a "collaborative scheme" for the dc voltage support when two converters on the MTDC operate with dc voltage droop characteristic.