基于损耗和谐波分析的多工况双馈风力发电机定子匝间短路故障研究

Research on Stator Short-circuit Faults of Wind Turbine Generator under Different Operating ConditionsBased on Loss and Harmonic Analysis

为了准确及时地识别并排除多工况下双馈风力发电机定子绕组匝间短路故障,通过ANSYS软件建立了新疆某风电场1. 5 MW双馈风力发电机的电磁场模型,对风机正常运行、风速突变、电网电压三相不平衡和机组低电压穿越工况进行仿真,处理后得到发电机的气隙磁密曲线。从损耗和谐波分析两个方面,以正常运行工况为标准对比研究发电机定子绕组匝间短路前后多工况特征量的变化。结果表明:发电机匝间短路后,基于损耗分析,不同的工况下电机的铁耗相较于故障前都有所增大;基于谐波分析,电网三相电压不平衡和低电压穿越工况的特定次谐波会导致更为严重的故障。

In order to accurately and timely identify and eliminate the inter-turn short-circuit fault of stator winding of doubly-fed wind generator( DFIG) under different operating conditions,the electromagnetic field model of a 1. 5 MW DFIG in a windfarm in Xinjiang is established by ANSYS software. The generator under different operating conditions of normal operation,sudden change of wind speed,grid voltage three-phase unbalance and low voltage ride-through is simulated,and the air gapmagnetic density curves of generator are obtained. The changes of characteristic quantity before and after inter-turn short-circuitare compared with that under normal operating condition from two aspects of loss and harmonic analyses respectively. Theresults show that,( a) based on loss analysis,the iron loss of generator after fault is increased compared with that before fault;and( b) based on harmonic analysis,the specific sub-harmonics under the operating conditions of grid voltage three-phaseimbalance and low voltage ride-through can cause more serious fault.