Dynamic thermal modeling of power transformers: further Development-part I

This paper focuses specifically on further refinement in the definition of nonlinear thermal resistances (by considering specific design differences between the transformer windings and vertical plates and, consequently, the fluid flow around their surfaces) and the relevant thermal models. In addition, the equivalent thermal capacitances of the transformer oil for different transformer designs and winding-oil circulations are estimated by the suggested equations. The methods presented in this paper are validated using experimental results. Furthermore, the IEEE-Annex G method is used as a reference