Electro-Thermal Modeling of ZnO Surge Arresters for Predictive Maintenance Support through Infrared Thermography Considering Porcelain and Polymeric Housings

The surge arrester is a strategic component for ensuring the reliability, continuity, and safety of power system operation, making it crucial to preserve the integrity of this device. This paper presents a multiphysics analysis of zinc oxide (ZnO) surge arresters with porcelain and polymeric housings under continuous operating voltage. Two surge arresters with voltage ratings of 228 kV and 240 kV were modelled in 3D based on manufacturer construction drawings, including the air gap between the ZnO blocks and the housing. The proposed methodology combines 3D electromagnetic simulations, used to determine the electric field distribution and the energy dissipation in the ZnO blocks, with 2D thermal simulations, in which heat sources are defined based on the dissipated energy and natural convection of the air surrounding the housing is considered. This procedure enables the generation of a realistic thermal profile, capturing the non-uniform distribution of losses along the equipment. The combined analysis of the thermal model and infrared thermography shows that the simulation effectively captures internal temperature distributions that are not accessible experimentally, providing a consistent and complementary understanding of the thermal behaviour of both surge arresters.