Stage transformer AC tap changer - uses parallel operating AC semiconductor control elements on various transformer taps

摘要

The stage transformer tap changer uses semi-conductor alternating current control elements that operate in parallel on various taps of the transformer. The control elements are connected to the drive providing the trigger pulses for the arrangement. An electronic switching device is associated with the drive and determines the time for switching over the transformer stages by means of monitoring the voltages on the control elements in a common direction. The electronic switching device preferably has a limit value generators as its input stage, which are connected via opto-electronic couples to a logic circuit which controls the drive in dependence on the output signals of the limit value generators.