Patent ID: 8519682
Filing Date: 2013-08-27
Classification: G05F,H01F,H01H

Abstract:
1. A hybrid on-load tap changer, for use in high voltage alternating current power transmission, comprising: a selector including two electromechanical isolating switches; a diverter including two legs defining respective current paths, each leg including a pair of opposed first and second semiconductor switches, each leg including a first inductor arranged in series between each pair of first and second semiconductor switches and the selector, and each leg including a voltage surge arrestor in parallel with each of the electromechanical isolating switches of the selector; a controller configured to switch on one of the first or second semiconductor switches of a given leg at a predetermined point within the alternating current cycle so as to commutate off a desired semiconductor switch in the other leg; and a snubber arranged in parallel with each pair of first and second semiconductor switches, wherein each of the electromechanical isolating switches includes a second inductor arranged in series therewith, each of the second inductors being arranged in series with the respective first inductors, and each of the electromechanical isolating switches and the respective second inductors being arranged in parallel with the corresponding voltage surge arrestor of each leg.