Research On Power Transformer Status Detection And Fault Diagnosis Based On Vibration Method

Research on transformer fault diagnosis is an important technology in the transformer industry. Although there are many valid methods to diagnose transformers, no methods can be used when the transformer is running. Diagnosis techniques using vibration method can not only detect the running transformer, but also achieve remote monitoring, and easy installation.Transformer vibration is caused by many components. The windings and the core is the most important sources of vibration. The proportion of the windings failure is higher than that of the core failure, and the windings failure has a close relation with the transformer status, so study the windings vibration is more practical. Recently, a simple windings model is already proposed, because the vibration transmission is so complicated, there is no model can describe the vibration of the tank surface. On the other hand, separating the windings vibration signals from the whole signals is an unsolved problem.In order to get a better model of the fundamental vibration, a numerical solution of electromagnetic forces is added to the existed windings model. Transformer windings are equivalent to a series spring mass damping system. The fundamental vibration is generated under the electromagnetic forces. In order to verify this model, sensors are fixed on the internal windings, and the vibration is measured.In order to study the transition procedure from the windings to the tank, a simple transfer function is proposed. According to the function, the transmission is equal to an attenuation and phase shift system. The entire windings are simplified to a mass spring damp system. The test is taken on a small size transformer.At the end, a vector superposition method of the windings and the core vibration is proposed. The method is verified by a data collected from a running transformer. A simple vector is proposed due to the abnormal sound from a transformer, using this vector the appearance of the abnormal vibration is reflected successfully.