【摘要】 针对电压源换流器型的高压直流输电(voltage source converter based high voltage direct current,VSC-HVDC)连接弱电网时,若逆变站采用定有功控制方式,由于受端电网旋转惯量较小而产生扰动下暂态频率偏移较大的问题。该文采用了一种虚拟转动惯量控制策略,将VSC-HVDC的逆变站模拟为同步发电机,以增加受端交流系统的转动惯量,为受端电网提供动态频率支持。进而,建立了系统的频率响应模型,给出了最大暂态频率偏移计算公式,并提出了暂态频率调整方法。利用PSCAD/EMTDC软件对3种扰动下不同虚拟转动惯性取值时的系统频率响应进行了仿真比较,仿真结果表明,所提出的设计虚拟转动惯量的方法不仅能够较好的抑制扰动下频率的波动幅度,减小暂态频率偏移,而且所占用的逆变站容量较小。更多还原

【Abstract】 When voltage source converter based high voltage direct current(VSC-HVDC) is used for weak grid connection with constant active power control, as the receiving weak grid with comparatively low or no inertia, which is easy to produce the large transient frequency deviation problem under the disturbances. This paper uses a virtual rotational inertia control strategy. The inverter station of the VSC-HVDC emulates a synchronous generation in order to increase the rotational inertia of the receiving weak system, which enables VSC-HVDC system to provide dynamic frequency support for the weak grid. The system frequency characteristic model is further built. The formula for the biggest transient frequency deviation calculation is obtained and the regulation method for the frequency deviation is proposed. The receiving system with different rotational inertia was tested under different disturbances using PSCAD/EMTDC. Simulation results show that the proposed method can better suppress the fluctuation frequency under the disturbances and the consumption capacity of the inverter station is the minimum.更多还原