Amplitude detection of power transformer tank vibrations signal

摘要

After switching on an unloaded transformer the time of magnetising current stabilisation is from 5 to 10 s, which clearly corresponds to image of vibrations recorded on the tank surface. The transformer tank vibrations in transient state are caused by vibrations both from windings and from its core. The mechanical quality of the two key elements of the transformer structure may be assessed using vibroacoustic analysis method, analysing the vibrations signal (accelerating of vibrations) recorded with the accelerometer attached to the transformer tank. The subject of the analysis is, in addition to other sizes and parameters, the envelope of the transformer tank vibration signal. Thus, it is important to accurately detect the vibrations amplitude in transient state. As the vibration signal does not meet the condition of AM signal definition, the article proposes an algorithm of a modified AM detector, which was successfully used in vibroacoustic diagnosis of the active part (winding and core) mechanical condition of power transformers.