低压穿越工况对大型DFIG的影响分析

Influences of Low Voltage Ride-through on Large Doubly Fed Induction Generator

文中针对1.5 MW双馈感应式风力发电机(doubly fed induction generator,DFIG)研究低压穿越对电机的影响。在理论分析的基础上,建立了基于PSCAD压降落程度下发电机实现低压穿越过程中电机内定、转子电流以及气隙磁通密度的变化,进而分析了低压穿越对双馈发电机造成的影响。结果表明,双馈风力发电机在实现低压穿越的前提下,定转子产生的冲击电流也会对绕组绝缘产生影响,同时气隙磁密会发生严重畸变。且电压降落程度越大,影响越大,这不利于发电机的安全运行。

To understand the influences of low voltage ride-through on 1.5 MW wind power doubly fed induction generator(DFIG), on the basis of theoretical analysis, a PSCAD based grid connection model and an Ansoft based generator model are established to study the changes of stator and rotor current and air gap flux density during the generator achieving low voltage ride-through(LVRT)under different degrees of voltage drop. Then,the influences of LVRT on DFIG is analyzed. The results show that in the premise of the wind power DFIG realiz-ing low voltage ride-through, the impulse current generated by stator and rotor will affect the winding insulation,and will cause serious distortion of air gap flux density, and these influences become greater with increasing volt-age drop, which will lead to negative effect on safe operation of the generator.