不平衡电压下基于负序电流法的双馈感应发电机定子绕组匝间短路故障仿真研究∗

摘要

Stator negative sequence current is one of doubly fed induction generator stator winding inter turn short circuit fault feature of voltage balance, but the actual three-phase voltage impossible completely symmetrical, produced by the asymmetric voltage of negative sequence current will influence the size of negative sequence current. In view of this, if not considering the influence of voltage unbalance only from the size of the negative sequence current fault misjudgment when the stator winding inter-turn short circuit fault, negative sequence current total caused by asymmetric voltage negative sequence current and stator winding inter-turn short circuit caused by structure. The mathematical simulation model of the voltage balance of the multi loop theory was established, stator winding inter-turn short circuit happened several case voltage unbalance and voltage unbalance. Get the fundamental component of voltage and current, negative sequence impedance method was used to eliminate by the voltage unbalance produced the influence of negative sequence current, negative sequence current caused by the fault alone obtained. Simulation results showed that, fault induced negative sequence current was less than the total negative sequence current.%定子负序电流是电压平衡情况下双馈感应发电机定子绕组匝间短路故障特征量之一，但实际中三相电压不可能完全对称，由不对称电压产生的负序电流会影响负序电流的大小。鉴于此，如不考虑电压不平衡的影响单纯从负序电流大小判别故障容易误判。当定子发生绕组匝间短路故障时，总的负序电流由不对称电压产生的负序电流分量及定子绕组匝间短路引起的负序电流分量构成。运用多回路理论建立数学仿真模型仿真电压平衡及电压不平衡情况下发生定子绕组匝间短路几种情况，得到电压和电流的基波分量，运用负序阻抗法排除由电压不平衡产生负序电流的影响，得到仅由故障引起的负序电流。仿真结果表明，故障引起的负序电流小于总的负序电流。