Experimental evaluation of electric and magnetic properties of structural steel

Purpose To present the proposition of a new experimental method for obtaining very crucial data of the structural steel that is used in the tank of oil filled power transformers. Namely, the volumetric losses and the magnetic permeability, both in function of the density of magnetic flux. Although these data are not usually available, they are fundamental for helping the transformer designer in avoiding the occurrence of hot spots in the transformer tank. The adoption of a conventional Epstein frame has restrictions because of the incompatibility between it and the samples of the steel. Design/methodology/approach The basis of the proposition is that same as of the Epstein frame, with significant attention paid to the additional losses in the winding that creates the magnetic flux to the samples, in the core. These losses can be significant and are created by the harmonics of current along the windings and summed to the ohmic losses. For separating these winding losses from the magnetic losses, each sampl...