Noise rejection and partial discharge source identification in insulation system under DC voltage supply

The problem to recognize the noise and identify the type of source generating discharges detected during campaigns of partial discharge measurements in an electrical apparatus is of utmost importance in the quality control, diagnostic, after laying testing and condition monitoring of DC insulation systems. This paper has the purpose to provide potential tools that are able to give considerable contribution into noise and partial discharge identification. In particular, the use of the T-F classification map, well assessed in AC, is able to cluster separately noise and discharges under DC supply as well. Then, simple algorithms involving the probability distribution of the amplitude values of the detected signals, as well as the recorded signal structure, could allow noise and PD identification, thus enabling noise rejection, and recognition and identification of the type of sources generating discharges.