VSC-HVDC 供电无源电网的频率控制策略

摘要

向无源网络供电的柔性直流输电系统在送端交流电网故障下，由于限流器作用，会使受端交流电网出现功率缺额问题，进而影响受端电网的电压稳定性。通过分析有功功率不平衡量，研究影响直流电压变化的机理，获得扰动下直流电压变化与频率响应之间的映射关系，进而提出逆变站的频率控制策略；利用负荷频率特性调节，将故障信息通过频率传递给保护装置，提高了系统故障穿越能力。PSCAD/EMTDC 仿真结果表明：所提出的控制策略能够有效地提高 VSC-HVDC 受端系统的故障穿越能力。%For the passive power grid with voltage source converter based high voltage direct cur-rent systems (VSC-HVDC)supply,if faults occurr on the sending network,the receiving net-work will suffer power shortage due to current limiter affecting.Furthermore,it may cause volt-age collapse.The relationship between DC voltage variation and dynamic frequency response un-der disturbance was analyzed,and the mechanism of DC voltage variation with active power un-balance was obtained in this paper.The frequency control strategies of inverter were thus pro-posed.According to the active demand of the load frequency regulation characteristics,the unbal-ance information was transmit to the protection devices,and the fault ride-through capability of the power grid was improved.PSCAD/EMTDC simulation results showed that the proposed con-trol scheme can improve the fault ride-through capability.