Condition Monitoring of Power Transformers Using Acoustic Signal Prony´s Analysis

On-load tap changers (OLTCs) are electromechanical devices used for voltage regulation on electrical networks. A noninvasive monitoring technique was developed using Prony´s method for condition assessment of on-load tap-changers using vibration analysis signals. The transient vibration signals emitted during a tap change are recorded and processed using Prony´s spectral analysis and standard pre-processing techniques. Traditional condition monitoring techniques exhibit a certain degree of complexity, which may be a serious drawback when designing portable low-cost maintenance equipment. In order to reduce this complexity, we introduce a new index based on Prony´s analysis. The proposed technique is presented and its diagnosis capabilities are evaluated using experimental results collected from field installed equipments during their maintenance inspection