Acoustic tap-changer analyses using continous wavelet transformation

摘要

The acoustic signature is a proven diagnostic tool in many industrial applications. In the process of OLTC operation the acoustic noise and vibration reflect mechanical or electrical events during the switching process. The information concerning the OLTC operation can be extracted from the vibro-acoustic measurements. The basis of this innovative method is the time frequency analysis of recorded acceleration signals by means of continuous wavelet transformation. Transformer vibrations, motor noise, the noise of tap selector and diverter switch as well as its sequence in time can be identified in a two-dimensional representation. An actual signature of an OLTC under test can be compared automatically with the corresponding reference signature by means of a pattern recognition algorithm.