Properties and gas production law of surface discharge in transformer oil-paper insulation

Incipient faults in transformer can degrade both oil and cellulose insulation, leading to the formation of dissolved gases. The authors investigate the relationship between incipient surface discharge and key gases. First, this paper presents the experimental platform and test method. Second, by means of statistical histograms and feature parameter analysis, the researchers made study on the surface characteristic. Third, several curves of feature gases (H<inf>2</inf>, CH<inf>4</inf>, CO, C<inf>2</inf>H<inf>6</inf>, C<inf>2</inf>H<inf>4</inf>, C<inf>2</inf>H<inf>2</inf>) were drawn and absolute production rate (APR) was introduced in the analysis. In addition, this work suggests that APR curves of H<inf>2</inf>, and CH<inf>4</inf> might reveal the severity of surface discharge by comparison. At last, based on the method of fuzzy comprehensive judgment and common membership function, the authors calculate the correlation factors of the data obtained in the experiment. Result shows that code ‘100’ has the maximum relativity with surface discharge.