Investigation of Ferroresonance Processes Leading to Thermal Damage of Cast-Insulated Transformers

In this paper, a study was made of ferroresonance phenomena in distribution networks with cast resin transformers, which can exist for a long time and lead to thermal damage to transformers. A description of transformer modeling technique based on the construction of its magnetic system substitution scheme, which allows to correctly account for its nonlinear characteristics in such processes, is given. Calculations of electromagnetic transients in EMTP and thermal processes in a transformer were carried out using COMSOL Multiphysics, where transformer design data was used to create models. Based on the results of the calculations, conclusions were drawn about the possible causes of damage to cast resin transformers.