Improvements on Thermal Performance of Power Transformers: Modelling and Testing

Abstract

Thermal performance of oil-immersed power transformer requires comprehensive solutions for the complex conjugate thermal-hydraulic problem which determines the thermal behavior of the oil and winding set. However, development of a thermal model without consideration of test procedures and limitations can led to inaccurate results during factory acceptance test (FAT). In the current study, we present improvements in modelling and testing based on an effective data exchange between both. Accurate loss calculation in transformer components and better investigation of oil behavior as well as development of more reliable rules to analyze heat-run results with consideration of new effective factors lead to a more accurate calculation of the thermal characteristics. This will increase the level of certainty in meeting the specified temperature rises during FAT, and therefore, accurate prediction of the transformer lifetime. Furthermore, minimum deviation between calculated and measured temperatures will allow optimization of the cooling system resulting in a more economical transformer design.