Joint Analysis of Vibration Signals and Switching Sequence Features of A Vacuum On Load Tap Changer

Vibration measurement of transformer vacuum on-load tap changer (VOLTC) can reflect its mechanical condition. In this paper, the Savitzky-Golay filter is used to process the vibration signal generated by the vacuum on-load tap changer. According to the switching process and the structure of the diverter switch, the filtered signal is segmented, and the origination of each vibration signal is determined. The segments improve the accuracy of fault diagnosis.

I. Introduction

The vacuum on-load tap changer(VOLTC)uses a closed vacuum tube to extinguish the arc, which has the characteristics of small size, low maintenance, good arc extinguishing performance, and not easy to cause oil carbonization^[1]. Nowadays, these VOLTCs are popular in converter transformers among DC transmission projects. Since the OLTC is responsible for voltage regulation, it is of great significance to maintaining its safe operation. Statistics show that tap-changer failures account for more than 20% of all transformer failures^[2]. Hence, it is of great importance to conduct condition monitoring OLTCs.