Investigation of insulation materials clearances in dry typetransformers with finite element method and experimental

Transformers are the most efficient electrical machines used in electrical energy systems. It is used with oily type and dry type transformers according to cooling types and usage areas. Dry-type transformers are preferred in most areas due to their features such as maintenancefree, non-flammable, and no explosion risk useful for today's conditions. Transformers must be suitable for continuous and safe operation without fault in operating conditions. While all these conditions are met, appropriate costs should be able to meet the customer demand. The cost of dry type transformer is directly affected by the design methods and the unique methods of the companies also affect the cost seriously. These methods, which aim to provide low cost with high quality, are mainly made on transformer dielectric clearances. In this study, studies were carried out on the optimum values of dielectric clearance in transformer design which directly affect the transformer cost. Experiments were carried out representing the dry type transformer phase-ground clearance and the results were evaluated with the Ansys Maxwell program which works with the logic of the finite element method. With the experiments, the breakdown voltages were determined according to the ambient conditions in the dry type transformer phase-earth clearance and graphs were created according to the results. Based on the interpretation of the graph for each ambient condition, the breakdown voltage can be estimated according to the dielectric clearance. This situation enables optimum dielectric clearance selection in transformer design and thus optimum cost.