Basics of Detailed Thermal-Hydraulic Model for Thermal Design of Oil Power Transformers

This paper presents the method for the calculation of temperatures inside oil power transformers, based on detailed thermal-hydraulic model. Starting from the construction of a transformer, physical parameters of applied materials, temperature of the outer cooling medium, and distribution of power losses, the calculation method delivers detailed distribution of temperatures: of the winding-in each conductor, of the oil-in each cooling channel and in each characteristic point, and in the core-on the surfaces and the hottest spots. The method is general [i.e., covers all oil circulation arts (ON, OF, and OD)]. Based on the method, the software for the thermal calculation of the majority of designs met in practice is developed.