A study of the relationship between insulating fluid viscosity and transformer cooling performance

Advances in the refining process for fire-resistant hydrocarbon fluids have yielded a 30% decrease in their viscosity. A study was undertaken to investigate the resulting changes in cooling performance. The results obtained show that a reduction in the viscosity of high-molecular-weight petroleum fluids yielded a lower operating temperature of the associated transformer. Lowering the viscosity of the fluid from approximately 14 to 11.5 cSt at 40 degrees C lowered the temperatures inside the transformer between 3.0 and 5.6%, depending upon the measurement location.<
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