Modified theory of modal analysis for the modelling of multiwinding transformers

With a view to optimal representation of multiwinding power transformers under test and service transient conditions, the authors present a modification to a model structure proposed previously by D.J. Wilcox (see ibid., vol.138, no.2, p.121-8, 1991). The development is applicable to all transformers, whether or not account is taken of frequency-dependent parameters and losses. The authors clarify the structural nature of the new modal model by treating the special case where losses are neglected and the parameters are taken to be independent of frequency. The importance of this special case is that it is definitive in revealing the character of the proposed modal approach