基于交流阻抗法的发电机励磁绕组短路故障诊断

Field Winding Short Circuit Fault Diagnosis on Turbine Generators Based on the AC Impedance Test

本文分析了励磁绕组短路故障对发电机转子交流阻抗的影响,在故障模拟发电机上进行转子交流阻抗试验,表明发电机发生转子绕组匝间短路后,转子交流阻抗变小。本文分析了励磁绕组短路故障对发电机静态等效电路的影响,提出了利用定子交流阻抗判断励磁绕组短路故障的方法。通过在故障模拟发电机上进行励磁绕组短路故障模拟试验,计算不同短路故障情况下定子交流阻抗值,并将其与正常情况下的定子交流阻抗值比较,当偏差超过一定数值时,可判断汽轮发电机存在励磁绕组短路故障。同时,将定子交流阻抗法试验结果和转子交流阻抗试验结果进行比较,分析定子交流阻抗法的有效性。定子交流阻抗法为离线监测方法,具有较高的灵敏度。

This paper analyses the variation of the rotor AC impedance after a field winding short-circuit fault.The rotor AC impedance test on the fault simulation generator indicates that the AC impedance of the rotor decrease because of the occurrence of a field winding short-circuit fault.This paper analyses the variation of the static equivalent circuit of the generator after a field winding short-circuit fault and proposes a way to diagnose field winding short-circuit fault by using the AC impedance of the stator.With the aid of short-circuit fault simulation test on generator,the AC impedance of the stator can be calculated at different short-circuit fault conditions,which is used to compare with the normal value.When the deviation exceeds a certain value,the field winding short-circuit fault within the turbine generator is recognized.Moreover,the effectiveness of the stator AC impedance method can be analyzed by comparing the result of stator AC impedance test,which is an off-line monitoring method with high sensitivity with that of the rotor AC impedance test.