Temperature Rise of Water-Cooled Power Transformers

This paper contains an analysis of the oil temperature rise of water-cooled power transformers. It is shown that by factoring the effect of viscosity oil temperatures can be calculated more accurately for a variety of conditions. Equations and curves are given with supporting test data for determining the temperature rise for different loads, ingoing water temperatures, and rates of water flow. The variations in temperature rise with load, water rate, and water temperature are appreciably different from published data on the subject. A discussion of winding hot-spot temperature is included, although no new test data are given.