双馈感应式风力发电系统低电压穿越研究

Research on Low Voltage Ride Through of Double-fed Inductive Generator Wind Power System

双馈感应式风力发电机组以其变流器容量小,有功和无功功率可独立解耦控制的特点,已成为目前变速恒频风力发电机组的主流机型。正因为双馈感应发电机(Double Fed Induction Generator,简称DFIG)的变流器容量小,所以它对电网电压扰动的抵御能力较弱。为防止扩大电网故障,目前欧洲电力系统要求风力发电系统具备低电压穿越(Low Voltage Ride Through,简称LVRT)能力。这里建立了简化的DFIG低电压穿越系统,在22 kW实验平台上进行了实验,其结果说明Crowbar电路能抑制电机定、转子电路中的暂态电流,系统基本具备了低电压穿越能力。

Due to the double fed induction generator＇s （DFIG） advantages of controlling active and reactive power independently and partly power converter, DFIG is becoming a popular type of wind power generation system.However, the converter is quite sensitive to grid disturbance because of its limited partial capacity compared with the generator rating. Nowadays the grid code in European demands that the wind power generator possesses the ability of low voltage ride through （LVRT）,in order to prevent the more severe successive grid faults.A simple LVRT system was built.The experimental results on a 22 kW platform prove that active crowbar circuit is able to reduce the transient current and the system realizes the LVRT ability.