Transformer Leakage Flux Models for Electromagnetic Transients: Critical Review and Validation of a New Model

This paper presents experimental validation of the coupled leakage inductance transformer model. It is shown that the coupled approach yields the same results as the indefinite admittance matrix method of BCTRAN. A topologically correct three-phase shell-type transformer model is proposed. The connection points between the leakage and magnetizing inductances are properly identified, which makes the new model superior to BCTRAN and the hybrid models by providing physical consistency. In addition, experimental verification of a method to calculate the short-circuit inductances is presented. New explanations on the division of leakage flux and on the mathematical equivalence between the T- and II-equivalent models are also given.