LVRT Control Strategy for VSC-HVDC Converter Integrated with Renewable Energy Collection System

When an asymmetrical fault occurs in the AC collection line of a renewable energy station connected to a VSC-HVDC(Voltage Source Converter High Voltage Direct Current) transmission system, the VSC-HVDC converter station may block due to overcurrent and overvoltage, leading to the disconnection of the renewable energy station and failure of the low voltage ride-through (LVRT) capability. To address this issue, this study first analyzes the mechanism of system overvoltage during faults in the renewable energy transmission system via VSC-HVDC, establishing the relationship between negative-sequence electrical quantities and non-fault phase voltages. Subsequently, a voltage reduction and current limiting control strategy based on locally measured electrical quantities is proposed for the VSC-HVDC converter. Finally, a simulation model of the renewable energy collection system connected to the VSC-HVDC converter is built in PSCAD, and the effectiveness and feasibility of the proposed control strategy are verified through simulations.