Insulation Condition Assessment Using Wavelet Analysis and Statistical Techniques

This paper presents wavelet analysis and statistical techniques for insulation condition assessment of equipment. In this study, the specific fault is made and placed on the terminal joint of a 25 kV power cable and the deterioration phenomena is accelerated by the overvoltage method. The deterioration phenomena of the internal insulation material are explained by wavelet analysis and statistical techniques using partial discharge (PD) current pulse waveforms. The maximum PD amount and the rise of the average discharge amount are shown before its breakdown, but the discharge numbers and the equivalent time-length of partial discharge current pulse waveforms are on the decrease, which means the large amplitude of current pulse and the short of equivalent time-length on the final stage of PD. The effectiveness and feasibility of the proposed method have been demonstrated.