A new model to study ultra-saturation phenomenon during the energization of a loaded three-phase power transformer and its effects on differential protection

摘要

The ultra-saturation phenomenon is one of the mal-operations of the power transformer differentialrnprotection that may occur during the energization of a loaded power transformer. This paper presentsrna new model for investigating the ultra-saturation phenomenon during the energization of a loadedrnthree-phase power transformer and considers its effects on the differential protection of the powerrntransformer. To model the ultra-saturation phenomenon, the nonlinear characteristic of the transformerrncore and the saturation effect of current transformers are taken into account. It is assumed that the loadrnof the power transformer is a resistive and inductive load. The mal-operation of the differential protectionrndepends on a variety of factors, the most important of which are residual flux and inception angle.rnIn this paper, the parameters mentioned will be studied in various scenarios. To verify the results of thernproposed model, the ultra-saturation phenomenon in an IEEE 14-bus test system is also investigated. Inrnthis paper, simulation is performed by the programs PSCAD and MATLAB. Copyright © 2015 JohnrnWiley & Sons, Ltd.