Condition monitoring of power transformer on-load tap-changers. Part 1: Automatic condition diagnostics

Automatic diagnostics for an on-load tap-changer (OLTC) requires a reliable technique that can classify vibration signals measured using an accelerometer mounted on the tank. In the paper, the authors investigate the automatic classification of OLTC vibration signatures using a self-organising map (SOM) and develop a feature extraction procedure that can extract essential features from the original vibration signature. The proposed SOM signature classifier is evaluated with a database established for one type of distribution class OLTC. The application results reveal the practical advantages of SOM for a number of tasks in OLTC condition diagnostics.