Temperature rise prediction of a natural cooling dry-type transformer

Dry-type transformer applications are growing in transformer market because the technology is non-flammable, safer and environmental friendly. Since no oil is present in a dry-type transformer for dielectric insulation, solid insulation is often used instead for compact dimensions which however constrains air convection as the major cooling approach. Therefore, how to accurately predict winding temperature rises when designing a transformer is one of the significant tasks of a transformer manufacturer. In this context, the present paper uses a natural cooled, solid insulation dry-type transformer as an example to illustrate the temperature rise prediction using a fast-calculating thermal network model and a highly discretized computational fluid dynamics (CFD) model. The model accuracies were then validated by comparing the prediction results with the heat-run test results.