Models Development for Core and Shell Type Autotransformers for Electromagnetic Transients Studies

The autotransformer is a complex arrangement of coils around a magnetic core with reduced spaces among the coils by their constructions form, that does the autotransformer have a significant capacitances and inductances. In this paper, are presented the equations to derive the inductance, capacitance and resistance from the physical windings dimensions for core or shell type autotransformers developed by the application of some electromagnetic laws to obtain the equipments models. The work includes the comparison from the admittances as frequency function, between the simulated models through the alternative transients program (ATP) and the measures from the autotransformer´s factory. The results are showing a similar behavior for the autotransformers input and transference admittances, ratifying the equations versatility to derive the windings parameters of these equipments