抽水蓄能机组多工况下转子匝间短路故障检测效果分析

Effect analysis of rotor interturn short circuit fault detection for pumped storage unit under multiple working conditions

转子绕组匝间短路故障在抽水蓄能机组内部形成了不平衡磁拉力,可导致机组剧烈振动,对该故障进行精准、实时检测十分必要。针对抽水蓄能机组运行工况多变的特点,利用在机组定子铁心上安装的U型检测线圈检测转子绕组匝间短路故障,以某水电站一台322 MW抽水蓄能机组为例,通过有限元软件仿真了机组空载工况、额定负载、发电调相、电动机负载和电动调相等典型工况,模拟了不同程度的转子绕组匝间短路故障,结果表明,故障后检测线圈感应电动势中均出现了分数次谐波,且其幅值随着故障程度的加重而增大,证明了U型检测线圈在抽水蓄能机组多工况下均可以有效反映转子绕组匝间短路故障,因此,U型检测线圈法适用于抽水蓄能机组的转子匝间短路故障在线诊断。

The rotor winding inter-turn short circuit fault forms an unbalanced magnetic pull inside the pumped storage unit,which can lead to severe vibration of the unit.It is necessary to accurately and realtime detect the fault.The U-type detection coil installed on the stator core of the unit is used to detect the inter-turn short-circuit fault of the rotor in view of the variable operating conditions of the pumped storage unit.Taking a 322 MW pumped storage unit in a hydropower station as an example,the typical working conditions of no-load condition,rated load,power generation phase modulation,motor load and electric modulation were simulated by finite element software.The inter-turn short-circuit fault of the rotor winding in different degrees was simulated.The results show that the fractional harmonics appear in the induced electromotive force of the detection coil after the fault,and the amplitude increases with the rise of the fault degree.It is proved that the U-type detection coil can effectively reflect the inter-turn short circuit fault of rotor winding under multiple working conditions of pumped storage units.Therefore,the U-type detection coil method is suitable for online diagnosis of inter-turn short circuit fault of rotor winding of pumped storage units.