Design & implementation of a 3-phase energy efficient switchable transformer controller using the PIC18F8720 microcontroller

Research on a switchable transformer has shown that improvements in transformer efficiency can be achieved by switching between series and parallel winding configurations. Random switching solid-state relays have been used to switch between the series, parallel and conventional configurations of a 3-phase, 3 kVA transformer. To control the switching to ensure maximum efficiency, to reduce the introduction of harmonics into the supply and to monitor the condition of the transformer, a controller has been implemented utilizing the PIC18F8720 microcontroller.