Electronic prototype for low-frequency heating of single-phase electrical transformers

Abstract

This work presents the development of an electronic system prototype to assist in the drying of single-phase electrical transformers by injecting sinusoidal low-frequency currents. The main component of the prototype developed here is a cyclo-converter, which is controlled through a field programmable gate array. The prototype includes control and regulation structures for the electrical and thermal variables that are associated with heating of the transformer under drying. A basic design modeled in MATLAB was used to develop the proposed system. Based on the simulation results, the design was adjusted and the control and estimation strategies of the transformer's temperature under heating were evaluated. The operation of the system, including the control of the heating temperature of the transformer under drying, was experimentally assessed by laboratory tests.