3D heating hazard assessment on transformer covers. Arrangement decisions

Abstract

Purpose

The purpose of this paper is to apply a 3D methodology to assess the heating hazard on transformer covers and present a practical tool to design amagnetic inserts arrangement.

Design/methodology/approach

A practical 3D methodology linking an electromagnetic analytical formulation with thermal finite element method is used for computation. Such methodology allows the evaluation of the temperature on metallic device elements heated by electromagnetic induction. This is a 3D problem which in the case of power transformers becomes especially difficult to apply due to the discretization requirement into the thin skin depth penetration compared to big machine dimensions.

Findings

From the numerical solution of the temperature field, decisions on dimensions and different amagnetic inserts arrangements can be taken to avoid hot spots on transformer covers.

Research limitations/implications

Some parameters presented in the model as heat exchange coefficients and material properties are difficult to determine from formulae or from the literature. The accuracy of the results strongly depends on the proper identification of those parameters, which the authors adjust based on measurements.

Originality/value

Differing from previous works found in the literature, which focus their results in power loss computation methods, this paper evaluates losses in terms of temperature distribution, which is easier to measure and validate over transformer covers. Moreover, an experimental work is presented where the temperature distribution is measured over a steel cover plate and a cover plate with amagnetic insert.

Citation

Penabad‐Duran, P., Lopez‐Fernandez, X.M., Turowski, J. and Ribeiro, P.M. (2012), "3D heating hazard assessment on transformer covers. Arrangement decisions", COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, Vol. 31 No. 2, pp. 703-715. https://doi.org/10.1108/03321641211200671