双馈风力发电机串补输电系统全运行区域的次同步特性分析

SSR Characteristics of a Wind Farm Connected to Series-Compensated Transmission System under All Operation Region of DFIG

针对双馈风力发电机串补输电系统中出现的次同步谐振(subsychronous resonance,SSR)问题,现有研究多是针对风机处于最大功率跟踪运行区域的情况进行的,不够全面;风机还有恒转速运行区域和定功率等其它运行区域。对双馈风机全部运行区域进行了分析,以华北地区某风电场实际的风机参数及运行方式为原型,建立了双馈风机与无穷大系统的线性化模型和PSCAD仿真模型,进而利用特征值分析和时域仿真方法对双馈风机串补系统全运行区域的次同步特性进行了研究,得到了SSR稳定区。结果表明:在低风速条件下,风机无论运行于最大功率跟踪状态还是其他运行状态都会发生SSR现象;随着风速增大,风机稳定运行区域的面积逐渐增大。据此,对实际风电场的稳定运行提出建议。

In most literatures related to subsynchronous resonance （SSR） in doubly fed induction generator （DFIG） based wind farm connected to series-compensated transmission system, the research is on the basis that the wind turbine is operated within the maximum power point tracing （MPPT） operating region, so the obtained conclusions are not comprehensive, since there are other important operating regions of DFIG such as fixed speed operating region, constant power operating region and so on. Firstly, all operating regions of DFIG are analyzed; then taking actual parameters and operating modes of wind turbine in a certain wind farm located in North China as the prototype, a small-signal model and PSCAD simulation model of single machine infinite bus system composed of DFIG and infinite bus system are built, and then using eigenvalue analysis and time-domain simulation the SSR Characteristics of a wind farm connected to series-compensated transmission system under all operation region of DFIG are researched and the SSR stable area are attained. Simulation results show that under low wind speed the SSR phenomenon will occur whether the DFIG is operated in MPPT region or in other operating regions;with the increase of the wind speed the area of stable operation region of DFIG gradually increases. On this basis, several rational suggestions on the stable operation of actual wind farms are put forward.