Study the thermal performance of electrical transformers with using new types of cooling fluids.

In this paper the electrical transformer is numerically studied besides the effect of cooling medium on its efficiency. The process of cooling the internal components of the transformer (coils and heart) also discussed, as well as the paper studyied the effect of the temperature of the external environment on the thermal performance of the transformers, especially for the summer season in hot regions, where the temperature reaches (51 °C). An electrical transformer with a capacity of (250 KVA) was chosen as a numerical model for the study and the use of nanofluid consist of pure transformer oil with nanoparticles of different types and mixing ratios. The numerical model was used to study the nanomaterials, where three nanomaterials were selected (silicon dioxide SiO2, copper oxide CuO and zinc oxide ZnO), respectively and in different ratios (1%, 2%, 3%, 4% and 5%). The study showed the effect of the nanofluid on the average oil temperature in the transformers and the results showed a remarkable improvement in the thermal performance. Two designs were proposed for the geometry fins. The standard, which is the design of the rectangular fins, and the other design was the triangular fins. The two designs achieved a decrease in the average temperature of the transformer with nanofluids. The thermal performance was improved after mixing the nanoparticles with pure transformer oil and the standard model recorded a decrease in the average oil temperature when the ratio (5%) to silicon dioxide was about (8.87 °C), for copper oxide by about (11.01°C) and zinc oxide by (10.91 °C) compared to pure oil at the same percentage above. The triangular fins transformer also recorded a decrease in the average oil temperature when the ratio of nanoparticle (5%) to silicon dioxide decreased by (9.33 °C), copper oxide by (11.43 °C) and zinc oxide (11.32°C). [ABSTRACT FROM AUTHOR]