The pyrolytic experiment and thermal dynamics analysis of insulating oil

The running status evaluation accuracy using insulating oil dissolved gas analysis is not high in the present oil-filled electrical equipment, and the dispute of using or not using the C3 gases as the characteristic gas, this paper used thermogravimetric analysis to explore the insulating oil thermal cracking characteristics. particularly, the pyrolysis experiment was done using the TGA/SD-TA851 thermogravimetric analyzer in the condition of temperature range 25 ~ 550 and static air atmosphere. The experimental material was the domestic Great Wall 25th new insulation oil. In the experimental process, the different heating rate (5°C, 10°C, 20°C, 30°C, 40°C/min) was set to explore the heating rate influence of insulating oil cracking characteristics. By the numerical fitting, we calculated the thermal dynamic parameters using differential method (Kissinger, Starink) and integral method (Coats-Redfern FWO) thermodynamic theory and equation, The experiment and calculation results show that (1) insulation oil pyrolysis process can be divided into three stages, the pyrolysis reaction order of the main area is 1; (2)the thermogravimetric curve mild right shift along with heating rate increasing; (3) the activation energy and frequency factor slight rise along with heating rate increase; (4) the difference of the insulating oil pyrolysis properties is not big for different heating rate; (5) the theoretical calculation result has a certain difference using different thermal dynamics equation, the Coats-Redfern equation calculation results most stable, the linear correlation coefficient is close to 1. Above the conclusions, it provided a certain experimental basis for exploring the mechanism of the insulating oil heat aging cracking and the process of C3, C4 hydrocarbon gas composition producing, and using C3 as possibility characteristic gas.