应用静止同步串联补偿器抑制风电次同步振荡的方法

The Suppression Method of Wind Power Sub-Synchronous Oscillation Using Static Synchronous Series Compensator

针对双馈风电场经串补系统外送功率时存在次同步控制相互作用(SSCI)问题,该文提出一种应用静止同步串联补偿器(SSSC)抑制SSCI的等效正电阻控制方法。该方法采用网侧线路中的电流作为输入信号,通过SSSC附加有源电阻控制(SARC)策略生成与线路中次同步电流同相位的次同步电压信号。SSSC实时跟踪该次同步电流信号,使其在次同步频率下等效为一正电阻。通过在网侧串接SSSC使网侧电阻增大,从而系统等值电阻被抬升至正值区域,进而达到抑制SSCI的效果。此外,详细介绍了SARC的结构及参数设计方法。最后,在PSCAD/EMTDC上搭建了华北某实际风电场时域仿真模型。仿真结果表明:多种运行工况下,SSSC可等效成正电阻使系统等值电阻处在正值区域,从而避免了系统发生SSCI。该方法具有参数整定简便、便于实现等优点。

In view of the problem of sub-synchronous control interaction(SSCI)when the doubly-fed wind farms transmit power through the series-compensated system,this paper proposes an equivalent positive resistance control method based on SSSC to suppress SSCI.The method uses the current in the grid side as an input signal and produces sub-synchronous voltage reference signal corresponding to sub-synchronous current in the line through the SSSC supplementary active resistance control(SARC)strategy.The SSSC traces sub-synchronous current to make it equivalent to a positive resistance at the sub-synchronous frequency.The grid side resistance is increased by connecting the SSSC in the line,and the system equivalent resistance is increased to a positive value region,thereby mitigating SSCI.In addition,the structure and parameter design method of SARC are introduced in detail.Finally,based on an actual wind farm structure in North China,the simulation model was built in PSCAD/EMTDC.The results show that the system equivalent resistance is in the positive region because SSSC is equivalent to a positive resistance under various operating conditions,thereby avoiding SSCI in the system.The method has advantages of simple parameters setting and easy realization.