应对岸上故障的海上风电多端柔直系统协调控制策略OA北大核心CSTPCD

This paper proposed a coordinated control strategy of multiple wind farm modular multilevel converters(WFMMCs)and wind turbines using energy control to address the issue of surplus power during faults in the onshore alternating current(AC)power grid of a modular multilevel converter based multi-terminal direct current(MMC-MTDC)system for offshore wind power.During the fault period,some WFMMCs first initiate energy control,raising the energy reference value based on changes in direct current(DC)voltage to absorb surplus power in the DC system.The remaining WFMMCs predict the DC voltage,and when the predicted DC voltage exceeds the limit,the remaining WFMMCs activate energy control to absorb surplus power.The WFMMCs adopt voltage reduction control on the wind turbine while absorbing surplus power and reduce the reference value of the AC voltage on the wind turbine side based on the increase in energy storage at the WFMMC.The grid side converter of the wind turbine adjusts the reference value of the d-axis current based on changes in AC voltage,reducing the active power transmitted to the MMC-MTDC system and avoiding the DC voltage exceeding the limit of the MMC-MTDC system.Finally,different types of faults were simulated in PSCAD/EMTDC to verify the effectiveness of the proposed coordinated control strategy.