经柔性直流接入的大规模直驱风电场等效建模与小干扰稳定性分析

含多台风机的大规模风电场经柔性直流接入交流系统的详细模型阶数过高,对小干扰稳定性分析和失稳机理研究提出了挑战.为此,建立了风电场经柔性直流接入交流系统的开环、闭环线性化状态空间模型.基于风电场开环状态空间模型及风电场节点电压电流关系,将全阶风电场模型通过单台风机动态及交流拓扑信息矩阵进行等效,并分析了风机输出功率、风机...

Equivalent modeling and small-signal stability analysis on PMSG-based large-scale wind farm connected to power system via VSC-HVDC

The order of the detailed model for large-scale wind farm with wind turbines integrated to AC system via VSC-HVDC(Voltage Source Converter-based High Voltage Direct Current) is too high, which brings challenges to the small-signal stability analysis and instability mechanism research. For that, the open-loop and closed-loop linear state space models of wind farm integrated to AC system via VSC-HVDC are built. Based on the open-loop state space model of wind farm and the relationship between the nodal voltage and current of wind farm, the full-order wind farm model is equivalent through the single wind turbine dynamic and the information matrix of AC topology, meanwhile the impacts of output power of wind turbine, interconnected location of wind turbine, topological structure of wind farm and number increase of wind turbines on oscillation mode damping of wind farm are analyzed. The closed-loop interconnected model of wind farm and VSC-HVDC system is derived based on the reduced-order model of wind farm, and the influences of possible strong dynamic interaction between two subsystems on the small-signal stability are analyzed when the number of wind turbines increases. The research shows that when the number of wind turbines increases, the damping of dominated oscillation mode decreases. When it is closed to an open-loop oscillation mode of VSC-HVDC converter, the strong dynamic interaction induced by modal resonance may cause the system instability.