Temporal Effects of Thermal Stresses on Solid Dielectric Materials under Diverse Voltage Conditions

Abstract

Dielectric materials are an essential part of the power system and their healthy condition is necessary for the stable system operation. Thermal stresses occurring due to faults have adverse effects on the life of insulating materials. To assess the effects of thermal stresses on the life of solid dielectric materials, this work attempts to investigate the effects of thermal stresses on their various parameters such as dielectric strength, thermal conductivity, breakdown time, etc. Effects on these parameters are assessed at different temperatures and time periods using constant and variable alternating current voltage sources. Simulations are performed in COMSOL Multiphysics 5.6. It was found that high temperature due to thermal stresses affects polymer structure, density, length, thermal conductivity, and breakdown strength of insulating materials. Results show that thermal conductivity increases by increasing time and temperature. Results of the study can be valuable for power system operators for the life assessment of field insulators.

Keywords

• breakdown strength
• thermal stress
• thermal conductivity
• solid insulator