新能源集群送出交直流系统多稳定问题演化机理及防控措施

Evolution mechanism of multiple stability problems and control strategies of AC/DC power system with large-scale wind turbine generators

大规模新能源集群送出系统故障演化过程中稳定形态交互演化,多直流同时换相失败过程中引发的电压、频率的大幅波动及功率振荡对电网的影响以及防控措施需进一步研究。为此,分析含大规模新能源的多直流送端系统换相失败引起连锁反应的机制,提出"暂态过电压导致大规模新能源脱网-弱通道功率转移导致暂态功角失稳-跨区域振荡失步解列"的三阶段演化机理,研究不同稳定问题演化链过程及典型模式,并从运行方式安排、动态无功补偿、风机涉网保护配置、紧急控制及解列控制等方面提出阻隔原则及防控措施。基于西北电网实际数据进行仿真分析,验证所提三阶段演化机理及防控措施的合理性与有效性。研究结论有助于运行人员提前掌握全局性稳定问题演化风险,指导大规模新能源集群送出交直流系统安全稳定运行。

There exist interactive evolution process of multiple stability problems of AC/DC power system with large-scale HVDC and wind power, such as voltage or frequency fluctuation and power oscillation, which can be caused by HVDC commutation failure. Further research is required on the evolution mechanism and control strategies of this kind of power system. In this paper, three-stage evolution mechanism is firstly proposed, including large-scale wind turbine generators tripping off caused by transient overvoltage, transient angle instability caused by power flow transferring in weak transmission section, and out-of-step separation caused by cross-regional power oscillation. Secondly, evolution processes and typical models of different stability problems are studied. From the aspects of operation mode arrangement,dynamic reactive power compensation,wind turbine network protection configuration,emergency control and decommissioning control,the prevention and control strategies are then proposed.Finally,simulation results and analysis based on real-sized power grid in China prove the rationality and effectiveness of the proposed three-stage evolution mechanism and control strategies.