Abstract: An on-load transformer tap changing system, for example for a power transformer, wherein the secondary or primary of a transformer includes at least one first tap and one second tap. A main connection circuit is used for permanent connection of the first tap or the second tap to an output terminal of the secondary or primary of the transformer. Secondary connection circuits are each used to connect a tap temporarily and directly to the output terminal of the secondary or primary of the transformer. Each of the connection circuits includes one or more insulated gate bipolar transistors. The system can be controlled without zero current value transition detection in the secondary winding.

Abstract: The invention relates to an on-load transformer tap changing system wherein the secondary or primary of a transformer comprises at least one first and one second taps (p1, p2). A main connection circuit (tra-I2) is used for the permanent connection of the first tap (p1) or the second tap (p2) to an output terminal (b2) of the secondary or primary of the transformer. Secondary connection circuits (I1, I3) are each used to connect a tap (p1, p2) temporarily and directly to said output terminal (b2) of the secondary or primary of the transformer. Each of said connection circuits (I1, tra-I2, I3) comprises one or more insulated gate bipolar transistors and the system can be controlled without zero current value transition detection in the secondary winding. Application: Power transformers.