Investigation on broadband characteristics of losses in power transformer interturn insulation paper by dielectric relaxation model

In order to complete the broadband simulation model of power transformer, the frequency dependent losses in power transformer inter-turn insulation paper was investigated. Three commonly used inter-turn insulation paper was selected, and the frequency dependent dielectric losses in the range of 10-10⁷Hz was measured. Based on the dielectric relaxation theory, the number of dielectric relaxation was determined according to the experimental data, and four typical model functions were applied to fit the experimental data. The consistency of fitting calculated by different model functions according to the experimental data was compared. The physical significances of fitting parameters were analyzed.