Patent ID: 9570252
Date: 2017-02-14
CPC Classifications: H01F,H01H

Claim:
1. A system for operating an on-load tap changer, the system comprising: a plurality of legs, at least one of which is triggered to switch from a first tap to a second tap of the on-load tap changer on receipt of a tap change signal, wherein each leg includes at least one mechanical switch, and wherein when at least one mechanical switch of at least one of the plurality of legs is switched on an electrical connection is established between one of the first and the second tap and a power terminal of the on-load tap changer; and a plurality of semiconductor switches, each semiconductor switch being placed parallel to the mechanical switches and when activated provide electrical connection between one of the first and the second tap and a power terminal of the on-load tap changer; a processing unit configured to selectively activate and deactivate the mechanical switches and the semiconductor switches in such a way that electrical contact is maintained between at least one of the taps and the power terminal during the transition of at least one leg from the first tap to the second tap without causing short circuit between two taps; wherein the processing unit is further configured to: generate the tap change signal to move the at least one leg from the first tap to the second tap when a condition for tap changing is met; generate activation signals for the semiconductor switches when the tap change signal is generated; and generate a plurality of deactivation signals for the mechanical switches of the at least one leg coupled with the first tap when a condition for tap changing is met.