A topology-based model for two-winding, shell-type, single-phase transformer inter-turn faults

Abstract

This paper develops a topology-based model for representing two-winding, shell-type, single-phase transformer inter-turn faults. The principle of duality between the electric and magnetic equivalent circuits is concisely explained. The magnetic equivalent circuit of a two-winding, shell-type, single-phase transformer is extended to the magnetic circuit of a transformer with an inter-turn fault. The model is implemented in the electromagnetic transients program using built-in component models. The model is verified against results published for a 150kVA three-phase transformer and experimental testing on 55kVA three-phase transformer constructed for internal fault testing. While the developed model is for single-phase transformers, extending it to a topology-based model for three-phase, three-legged and five-legged transformers is straight forward. This model may find usage in transformer relay protection studies.