一起220kV变压器绕组变形缺陷的诊断分析与解体验证

Diagnosis and Verification on Deformation Fault of 220 kV Transformer Winding

文中介绍了一起停电试验发现的220 k V变压器低压绕组变形缺陷,为变压器累积效应的理论研究和变压器故障检测的试验研究提供现场数据诊断案例。试验检修人员首先根据变压器短路阻抗试验和绕组变形试验结果,推断出低压绕组发生不同程度变形;并结合该变压器历年遭受短路冲击后的色谱分析试验结果,综合分析、诊断发生变形的原因,主要由于低压侧短路电流冲击及绕组变形的累积效应。通过返厂解体发现,其低压绕组发生不同程度的变形,并存在过热现象,验证了试验和诊断结果。通过变压器绕组变形试验诊断,有效避免了一起设备潜伏性故障的发生,并给出变压器日常维护检修的注意事项及相关建议。

A deformation fault of the lower-voltage winding in a 220 kV transformer, which was found in routine tests, is described in this paper. First, according to the results from the short-circuit impedance test and the winding deformation test, different degrees of deformation fault of low-voltage windings were deduced. Then considering the historic ehromatograms of the transformer, which were obtained after every shock of short-circuit current, and the diagnostic result, the cause of the deformation fault was due to the shock of short-circuit current at low-voltage side and the cumulative effect of winding deformation. Disintegration inspection revealed that different degrees of deformation and overheating happened in the low-voltage winding, verifying the correctness of the results from diagnosis and tests. As a result, the routine tests helped to prevent a latent failure of the transformer. In addition, some suggestions are offered for routine maintenance and overhaul of transformers.