Abstract: To investigate the correlation between the pyrolysis temperature of cable insulation materials and the insulation failure temperature of cables, the pyrolysis temperature of cable insulation materials and the insulation failure temperature of cables were obtained respectively through thermogravimetric analysis experiments and radiation heating experiments. In the study, Class 1E cables were used, and the influence of thermal aging on the experimental results was considered. The results indicate that the pyrolysis temperature when the first peak of the DTG curve of the cable insulation material appears is essentially the same as the insulation failure temperature obtained by using the criterion of a one order magnitude of decrease in cable insulation resistance as the determination standard for cable failure, with an error of less than 10%; The pyrolysis temperature when the DTG curve starts to deviate from the horizontal curve is essentially the same as the insulation failure temperature obtained by using the criterion of a two order magnitude of decrease in insulation resistance or by drawing a tangent at the maximum slope of resistance decrease and taking the intersection point with the critical value as the determination standard for cable failure after 120 h and 264 h of thermal aging, with an error of less than 20%; While the insulation failure temperatures obtained by using other cable insulation failure determination standards differ significantly from the pyrolysis temperature.

Key words: cable, insulation material, pyrolysis characteristics, insulation failure temperature