计及Crowbar投入时间影响的双馈感应风力发电暂态全过程研究

Research on transient full process of doubly-fed induction generator considering Crowbar protection insertion

针对撬棒(Crowbar)保护的双馈感应风力发电机(DFIG)暂态特性分析,常规研究为简化求解过程,均认为故障发生时Crowbar保护瞬间投入,忽略了不同程度的Crowbar动作延时,对DFIG暂态过程的精确分析造成一定影响。为此,对计及撬棒保护投入时间影响的双馈感应风力发电机暂态全过程进行了详细分析,依据故障特征及Crowbar保护动作情况将电网电压故障全过程分为三个阶段进行研究:第一阶段为故障发生,定子电压跌落,但Crowbar保护尚未投入;第二阶段为经过短暂的延时,Crowbar保护投入,同时转子侧换流器封锁;将电网电压恢复后的动态响应作为第三个阶段。仿真结果表明,随着Crowbar保护投入延时的增加,DFIG的瞬态性能将恶化;在设置Crowbar电阻时,应考虑故障全过程中转子电流的最大值并计及Crowbar保护投入延时的影响。

Aiming at Crowbar protection transient characteristics analysis of doubly-fed induction generator(DFIG),in order to simplify the solving process,the conventional research considers that Crowbar protection is instantaneous input when the fault occurs,ignoring the Crowbar action delay with different degrees,which has a certain effect on the precise analysis of DFIG transient process.Consequently,the transient whole process of doubly-fed induction wind turbine,which takes into account the input time of Crowbar protection,is analyzed in detail.The whole process of grid voltage fault was divided into three stages according to the fault characteristics and Crowbar protection action.In the first stage,the fault occurred and the stator voltage dropped,but the Crowbar protection was not put into operation;in the second stage,after a short delay,the Crowbar protection was put into operation and the converter at the rotor side was blocked;the dynamic response after the power grid voltage recovery was taken as the third stage.The simulation results show that,with the increase of Crowbar protection input delay,the transient performance of DFIG deteriorates.When setting the Crowbar resistance value,the maximum value of the rotor current in the whole process of the fault is considered and the effect of the Crowbar input delay is also taken into consideration.