Study of protection strategy for VSC based HVDC system

This paper studies the operation performance of a voltage source converter (VSC) based HVDC (VSC-HVDC system) system under some characteristic faulted conditions with and without protection measures. A protection strategy is proposed to enhance the continuous operation performance of the VSC-HVDC system. The strategy utilize a newly developed over-current limitation controller to suppress the VSC over- currents and use a voltage chopper to suppress over-voltages on the DC side of the VSC. Digital simulation is done to verify the validity of the proposed protection strategy.