双馈风机的两种负荷频率控制方法分析与比较

Comparison of Two Frequency Control Strategies by DFIGs

在风电机组参与调节系统频率的过程中,由于双馈风电机组的有功,无功功率解耦控制的特性,难以在频率发生变化时,通过改变有功功率的输出保持系统惯性,实现调节系统频率的目的。为解决上述问题,通常采用两种风机参与电力系统一次调频的频率控制策略:惯性控制策略和下降速率控制策略。分析比较了两种控制策略在风机参与系统频率控制的效果,结论表明:双馈发电机有功快速调节的良好特性并没有在惯性策略中体现出来,反而导致常规电源在抑制负荷扰动的响应延迟增加。而下降控制策略保持了风机有功快速调节的良好特性,使风机更好的参与有功的调节。

The presence of a large wind power penetration leads to a reduction of power system frequency regula- tion capabilities. To make up for that system change, wind turbines should actively provide frequency response upon request. To aehieve that goal, control of active power output in response to system frequency is a necessity. There are two frequency control strategies which are common used in the active power control of the variable speed wind tur- bines： inertial control and speed -droop control. However, these strategies are usually used separately. It is hard to say which provides quick frequency response upon request. Therefore, the two frequency control strategies by DFIGs in electrical system were compared. The results indicate that, in comparison to inertia control, the speed - droop control allows DFIGs to provide frequency response upon request quickly.