A transformer system includes: a main transformer including a primary winding coupled to AC mains and a secondary winding; a load circuit including a load switch configured to be coupled to a load, the load circuit being coupled to the secondary winding of the main transformer; an auxiliary power supply coupled to AC mains; a controller coupled to an output of the auxiliary power supply; an electronic switch between the AC mains and the primary winding of the main transformer and configured to be controlled by the controller; and a load detector coupled to the load circuit and configured to detect whether the load is connected to the main transformer and to output a load signal to the controller in accordance with whether or not the load is connected to the main transformer, wherein the controller is configured to control the electronic switch in accordance with the load signal.