Mohamed Abdelaziz Abdelwahed
Wind Power Curtailment and DC Overvoltage Control During Permanent Converter-Outage for Multi-Terminal HVDC Systems
Multi-terminal high-voltage DC (MT HVDC) transmission systems are a promising technology for the aggregation and integration of wind power from offshore wind farms (WFs). However, due to the possibility of AC faults in mainland grids, which may lead to outages in the power-receiving converters, converter-outage fault-ride-through (FRT) capabilities are a crucial requirement for enhancing system reliability. This paper presents a communication-free FRT control strategy for mitigating the effects of the overvoltage in a DC network as a consequence of the power imbalance caused by permanent or temporary power-receiving converter outages. The proposed FRT control strategy is targeted at fast power reduction of the wind power generation from the WFs in order to eliminate power imbalances in the HVDC network. This process is based on decentralized FRT control rules in the local controllers of the WF voltage source converter (VSC) and its wind turbines. The proposed strategy was designed to work with WFs based on both doubly fed induction generators (DFIGs) and permanent magnet synchronous generators (PMSGs). The proposed FRT control strategy has been validated with respect to mitigating the effects of converter outages through testing on the B4 CIGRE MT HVDC test system using Matlab/Simulink software.