The present invention relates to an on-load tap changer device, which allows the automatic regulation of voltage in the secondary winding (28) of high-voltage electrical equipment (26, 65) by selecting the number of turns of the primary winding (27) by means of an on-load tap changer device (1, 40), having reduced volume and weight, obtaining the highest possible number of transformation ratios without changing the constructive arrangement of the high-voltage electrical equipment (26, 65).

The present invention relates to an On-Load Tap Changer (OLTC) for connection to a regulating winding of a transformer, the regulating winding enclosed in a transformer tank, wherein the transformer tank includes insulating liquid, the OLTC comprising: a switching device including: a main contact, and a resistor contact, wherein the main contact and the resistor contact are configured to be arranged directly in the insulating liquid and that they are configured to be physically separated from the insulating liquid, and wherein the main contact is enclosed in a main contact enclosure and the resistor contact is enclosed in a resistor contact enclosure. The present invention further relates to a transformer comprising the OLTC as disclosed herein.

A tap changer assembly includes a tap changer assembly housing completely enclosing a tap changer volume and an overflow volume. The tap changer assembly includes at least a part of a tap changer located in the tap changer volume. The tap changer volume and the overflow volume are connectable to each other via an overflow assembly. When a pressure in the tap changer volume is equal to or higher than the predetermined overflow pressure threshold, fluid communication between the tap changer volume and the overflow volume via the overflow assembly is enabled, and is prevented when the pressure is lower that the threshold. when fluid communication is enabled, an area at least 10% of a largest internal cross-sectional area between the tap changer volume and the overflow volume is enabled for fluid communication via said overflow assembly.

A circuit (15) for an electrical plant (10) with a first and a second control winding (11, 13) comprises a first on-load tap changer (16) with a first diverter terminal (161) and three first switch terminals (162), of which at least two can be connected with associated first taps (12) of the first control winding (11); and a second on-load tap changer (17) with a second diverter terminal (171) and three second switch terminals (172) of which at least two can be connected with associated second taps (14) of the second control winding (13);
wherein the second diverter terminal (171) is connected with the first diverter terminal (161) or with a first switch terminal (162) not associated with the first tap (12).

An on-load tap changer includes a static unit including fixed contacts for connection to taps at a transformer winding, a dynamic unit including at least one movable contact for selectively contacting one of the fixed contacts during operation of the transformer, and includes a rotational positioning device for adjusting the rotational position of the dynamic unit relative to the static unit during at least one of assembly or disassembly of the tap changer.

An on-load tap changer of a resistor type includes a selector base plate; a selector mounted on the selector base plate; a diverter switch base plate; a diverter switch mounted on the diverter switch base plate and having a transition resistor; and a common drive shaft which is configured to actuate the selector and the diverter switch.

An electrical system (1) for a three-phase alternating current network, comprising a transformer (20U, 20V, 20W) with a primary side (30U, 30V, 30W) and a secondary side for each phase (U, V, W) of the alternating current network; a separate transformer housing (60U, 60V, 60W) for each transformer (20U . . . W); and a switching assembly (100) connected to the transformers (20U . . . W); wherein the primary side (30U . . . W) and/or the secondary side has a main winding (21, 22, 23) and a regulating winding (31, 32, 33) in each phase; the switching assembly (100) is designed such that it can connect each regulating winding (31, 32, 33) with each of the main windings (21, 22, 23); and the switching assembly (100) is arranged in one of the transformer housings (60U . . . W) or in an own switch housing (70).

A diverter switch, which is for an on-load tap-changer, includes a housing; and a carrier. The carrier has elements configured to carry out a diverter switch operation. The carrier and the elements are at least partly encapsulated in the housing.

A transformer arrangement includes a transformer, a transformer tank and at least one tap changer that is arranged to be connected to said transformer. The transformer arrangement further includes at least one support structure which is arranged to be connected to the tap changer and to extend between the tap changer and at least two support members located between the tap changer and at least two points on an inner surface of the transformer tank. The at least one support structure is arranged to reduce pendular movement of the tap changer.

A support module (10) for polarization resistors of an on-load tap changer comprises:a supporting region (11) for at least one polarization resistor; a first joint region (13); a second joint region (14) which is compatible with the first joint region. A support frame (19) for polarization resistors of an on-load tap changer comprises:two such support modules which are joined by virtue of the second joint region of the first support module bearing at least partially against the first joint region of the second support module. A fastening element (24) for polarization resistors (22) comprises:two electrically conductive accommodating sections (25), which each have an accommodating opening (27) for one of the ends (23) of a polarization resistor (22);an electrically conductive connecting section (26), which connects the two accommodating sections (25) mechanically and electrically to one another;a first piece (28.1), which comprises the first accommodating section (25.1) and an adjoining first part of the connecting section (26); a second piece (28.2), which comprises the second accommodating section (25.2) and an adjoining second part of the connecting section (26); wherein:the first and second parts are in the form of a plug-type connection.