应用于双馈风机高低压穿越的定子串联阻抗保护方案

Stator Series Impedance Protection Scheme for High-voltage and Low-voltage Ride-through of DFIG Wind Turbine

针对双馈感应发电机DFIG(doubly-fed induction generator)的高、低电压综合故障穿越,充分利用转子变流器对定子电流的调节能力,提出一套串联阻抗与定子动态无功电流配合的故障穿越方案及协调控制策略。在电网故障期间,该保护方案通过及时投入定子串联阻抗,保障转子变流器的控制能力,并动态调整定子无功电流,利用串联阻抗的分压作用补偿电网故障电压。以充分利用定子无功容量为目标,给出了串联阻抗的整定方法。该方案保障了高电压故障下DFIG的定子绕组安全,提高了故障穿越期间转子侧变流器的控制能力,提供了符合并网导则的无功支撑电流。基于RTDS硬件在环仿真平台验证了该方案的有效性。

For the high-voltage ride-through(HVRT)and low-voltage ride-through(LVRT)requirements for a doublyfed induction generator(DFIG),a fault ride-through scheme and the corresponding coordinated control strategy using series impedance and stator dynamic reactive current are proposed,which fully take advantage of the converter’s capability of regulating the stator current.During the grid fault,this protection scheme puts in the stator series impedance instantly to guarantee the control capability of the rotor-side converter.In addition,it dynamically adjusts the stator reactive current and compensate the voltage under grid fault by means of the partial voltage of series impedance.The setting method for series impedance is given to make full use of the stator reactive capacity.This scheme guarantees the safety of the stator winding of DFIG under high-voltage fault,improves the control capability of the rotor-side converter during fault ride-through,and provides reactive support current that satisfies the grid-connection requirements.The effectiveness of the proposed scheme was verified based on an RTDS hardware-in-the-loop simulation platform.