异步风电机组接入系统的小干扰稳定及控制

Small Signal Stability and Control of Wind Turbine with Asynchronous Generator Integration into Power System

在电力系统分析软件DIgSILENT/Power Factory中建立基于普通异步发电机的风电机组(异步风电机组)和电力系统模型,分析异步风电机组对电力系统小干扰稳定性及阻尼特性的影响。提出了一种改进的桨距角控制方案——将系统频率偏差信号引入桨距角控制系统。在系统发生低频振荡时,通过调节桨距角控制异步风电机组输出功率,使风电场输出功率与系统功率振荡的频率相关。对系统进行特征值分析和故障时域仿真,2种分析结果都表明,改进的桨距角控制环节能够改善系统阻尼,对系统功率振荡具有很好的阻尼和抑制作用,加强了系统动态稳定性。

The models of conventional wind turbines with an asynchronous generator and power system are developed in DIgSILENT/Power Factory. Based on the model, the impacts of wind turbines with an asynchronous generator on the smallsignal stability and damping characteristics of power system are analysed. An improved pitch control scheme is presented by introducing a frequency deviation signal into the control system. When low frequency oscillation happens, the wind turbine output is regulated to correlate with system oscillation frequencies. Both frequency domain analysis and time domain simulation results demonstrate that the improved pitch control methods significantly improve the damping characteristics of power system. Therefore the power oscillations are mitigated and the system dynamic stability is enhanced effectively in the system.