Estimation of design parameters of single-phase distribution transformers from terminal measurements

In this paper, a novel method is proposed for the estimation of the design parameters of single-phase distribution transformers using data acquired from terminal measurements along with nameplate data and external tank dimensions. Transformer parameters that can be measured from terminals, for example, leakage inductance, saturation inductance, andwinding resistance, are considered first. These parameters are analytically correlated with the geometrical information of the transformer structure. A system of nonlinear equations is derived accordingly. Winding dimensions and the number of turns are computed with acceptable engineering accuracy. The core dimensions (including its crosssectional area) are calculated using winding information. The obtained data can be utilized to develop white- or gray-box models to be used in the investigation of the thermal and/or electromagnetic behavior of power transformers as presented in several research studies published to date.Examples on laboratory and utility-grade transformers are shown for illustration and validation of the proposed design parameter estimation method.