并网型双馈式风力发电系统广域阻尼控制器设计

Design of Wide-area Damping Controller of Grid-tied Wind Generation System Based DFIG

随着接入电力系统的风电规模越来越大,风电场发出的电能需要经过远距离输送到负荷中心。由于风电场输出功率的波动性及远距离输电等原因,大规模风电场接入互联电力系统后会面临不同区域电网间的低频振荡。为此,设计了广域阻尼控制器以有效抑制双馈风力发电系统并网带来的互联系统的低频振荡问题。首先,建立了大型双馈风力发电系统的小信号动态模型,该模型包括风力机及传动系统动态方程、异步发电机动态方程、变频器动态方程3个部分,具有一般性。以双馈式异步发电机(DFIG)转子侧变流器有功功率参考值为输入,然后,以互联电力系统区域间同步发电机功角差值为输出,通过系统辨识方法得到二者间的开环传递函数。最后在此基础上,利用极点配置方法,设计了双馈风力发电机的广域阻尼控制器。非线性时域仿真表明,配备了阻尼控制器的大规模风电场能够有效抑制互联系统的低频振荡,增加系统的阻尼。

Because of the variation of output power of wind power field and long-distance transmission,inter-area oscillation is an issue in interconnected power systems which are connected with large-scale wind farms.Consequently,a wide-area damping controller was designed which could effectively suppress the low frequency oscillation of the interconnected power systems because of the double-fed wind power generation system.A small signal model for large-scale wind power generation system was established,which consisted of three parts,i.e.,the small signal model for wind turbine and its drive system,asynchronous generator and converter equation,control system of converter.Taking the rotor-side converter＇s active power reference of DFIG as the input signal and the rotor angle difference of interconnected power systems as the output signal,the opened-loop transfer function between the two signals was obtained by system identification method.Based on the opened-loop transfer function,DFIG＇s wide-area damping controller was designed in terms of pole placement technology.Nonlinear time-domain simulations demonstrate that large-scale wind farm equipped with the designed damping controller can effectively suppress the low frequency oscillation of the interconnected power systems.