New thyristor assisted diverter switch for on load transformer tap changers

Based on a conventional tap changer, a new diverter switch is described which features a single transition resistor and thyristor assisted suppression of arcing at the switch contacts. A simple arrangement of mechanical switch contacts ensures that the thyristor pairs used for arc suppression are only connected and triggered for a short interval of time prior to, during and after the operation of the switch contacts. A thyristor malfunction will not result in damage to the tap selector or transformer