A coordination control strategy to suppress commutation failure based on LCC-VSC

Abstract

The receiving end hybrid LCC-VSC system is a new type of hybrid DC transmission system. In order to suppress continuous commutation failure, this paper optimizes and improves the firing angle control strategy of LCC with AC fault voltage and the DC power recovery to predict the commutation failure. And the reactive power compensation value is determined according to the degree of voltage drop and attached to the reactive power outer loop control link of multiple VSCs. By increasing the VSC output The reactive power plays a role in restraining the commutation failure. Based on the receiver-end hybrid LCC-VSC model in PSCAD/EMTDC, the proposed LCC-VSC control strategy is simulated and verified. The simulation results show that when the AC voltage drops, the proposed control strategy can effectively suppress the drop of the turn-off angle and avoid the occurrence of continuous commutation failure.

Keywords

• Hybrid HVDC
• Commutation failure
• Prediction control
• Reactive power
• Coordinated control