大规模风电直流外送方案与系统稳定控制策略

针对大规模风电集中外送,论证了风电孤岛直流外送、风火打捆孤岛直流外送、风火打捆联网直流外送3种方案,重点从频率稳定、电压稳定方面研究各方案的安全稳定问题,分析了风功率波动、送端交流线路短路等典型扰动形式对系统稳定性的影响,通过比较给出了合理的大规模风电直流外送方案。在此基础上,以酒泉风火打捆特高压直流外送规划系统为对象,研究系统安全稳定问题,提出了利用直流调制跟随风功率波动、改善系统稳定性的控制策略,通过仿真计算验证了所提出控制策略的有效性。

HVDC Grid Connection Schemes and System Stability Control Strategies for Large-scale Wind Power

For large-scale wind power transmitted by direct current(DC) system,three solutions are discussed including wind power island system transmitted by DC system,wind-coal-bundle island system transmitted by DC system,and wind-coal-bundle interconnected with AC system transmitted by DC system.The security and stability of these solutions are studied,especially the frequency and voltage stability problems,and the influence of wind power fluctuation and line-to-ground fault on the systems are discussed.The most appropriate solution of large-scale wind power transmitted by DC system is presented.Based on the results,system security and stability is studied for the Jiuquan wind-coal-bundle transmitted by ultra high voltage direct current(UHVDC) system,and the control strategy based on the DC modulation control method is proposed to mitigate the impact of wind power fluctuations on system frequency and improve the system stability.The validity of control strategy is verified by simulation.