水轮发电机转子绕组匝间短路故障的新型在线诊断方法

A new on-line fault diagnosis method of inter-turn short circuit fault in rotor winding of hydro-generator

针对转子绕组匝间短路故障可引起水轮发电机机组较为强烈的振动,导致计划外停机的问题,以二滩水电站一台550 MW水轮发电机为例,根据磁动势平衡原理,推导匝间短路前后发电机主磁场的变化规律,提出在水轮发电机定子铁心上安装U型检测线圈,用以检测转子绕组匝间短路故障。根据发电机主磁场的运动规律,推导穿过U型检测线圈的磁通表达式,进一步得到检测线圈的感应电动势。二维电磁场仿真证明U型检测线圈的感应电压可以反映水轮发电机的转子绕组匝间短路程度,并能定位故障磁极位置,新型检测方法实现了对水轮发电机转子绕组匝间短路故障的在线诊断。

Aiming at the problem that the rotor winding inter-turn short circuit fault can cause the hydro-generator set to vibrate more violently,which leads to the unplanned downtime,taking a 550 MW hydroelectric generator at Ertan Hydropower Station as an example,according to the principle of magnetomotive force balance,the variation law of main magnetic field of the generator before and after inter turn-short circuit fault was deduced.A U-type detection coil was proposed to be installed around the stator core of hydrogenerators,which could be used to detect the inter turn short circuit fault of rotor windings.According to the motion law of generator main magnetic field,the expression of flux passing through the detecting coil through U type was derived,and the induction electromotive force of the detecting coil was further obtained.The 2-D electromagnetic simulation proved that the induced voltage by U-type detection coil can reflect the short-circuit level of rotor windings in hydro-generators,and locate the faulty-pole position.By using the new detection method the on-line diagnosis of the inter-turn short-circuit fault of the rotor winding in hydro generators is realized.