Non Isothermal Thermo Gravimetric Analysis (TGA) Measurements of Oxidative Aged Solid Insulation

Transformer is a major electrical apparatus in the power system network that determines the reliability and continuity of power supply. Solid insulation is one of the key components in the transformer. Kraft paper as solid insulation performs the function of insulating the windings. Thermal and electrical stresses are the key reasons for degradation of kraft paper and this degradation can be studied using various analyses. In this paper, a non-isothermal thermogravimetric analysis is performed to study the response of degraded kraft paper. The samples considered in this study are vacuum dried fresh kraft paper, 300, 600, and 900 hours oxidative aged kraft paper. Thermal degradation characteristics of the solid insulation are studied in the temperature range of 30°C to 900°C with a ramp rate of 20°C/min. Nitrogen gas is used as purge gas to provide an oxygen free environment. Results are found to be corroborative with aging status.