Frequency domain characteristics and insulation condition evaluation of power transformer oil-paper insulation

Based on the platform designed for thermal aging test of oil-paper insulation system, the problem of thermal aging of solid insulation used in the oil-paper insulation of power equipment has been studied. The method of Frequency Domain Spectrum (FDS) has been applied to obtain frequency domain dielectric response properties of oil immersed paper insulation, and an unscrambling method according to Universal Relaxation Law (URL) has been proposed and the characteristic frequency parameter fp used to describe dielectric response properties of oil immersed paper insulation has been extracted from FDS data. It shows that the proposed unscrambling method and the characteristic frequency parameter fp are effective in aging condition assessment of oil-paper insulation.