Vibration measurement and signal processing for condition assessment of OLTC of transformer

Vibration measurement is a non-invasive technique for online condition monitoring and assessment of power transformer´s On-Load Tap Changer (OLTC). In this paper novel signal processing techniques are proposed for evaluating conditions of tap positions of OLTC. Firstly, a signal pre-processing procedure is performed for obtaining a simplified vibration signal waveform of tap positions. Then, a correlation analysis is conducted for comparing waveforms of different tap positions and evaluating their conditions. The above techniques have been implemented on an OLTC condition monitoring system and verified through vibration measurement on the OLTC of a power transformer.