Modeling transformers with internal faults based on magnetic circuit. Part I: Models

Internal fault detection in transformers provides early warning of electrical failure and could prevent forced outages with the consequential costs. To detect and diagnose transformer internal faults it is required a model. This paper presents a methodology to model internal transformer faults. The short circuit model was developed on base of the behavior of the windings when this fault occurs. The aging model was developed based on the physical behavior of aging insulation.