Abstract: 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).

Abstract: A motor drive for actuation of an on- or off-load tap changer the drive has a drive motor, a load transmission having a first drive shaft carrying a first drive wheel and connected with the drive motor and a second drive shaft carrying a second drive wheel, and a mechanical coupling between the first and second drive wheels. The second drive shaft is operatively connected at a first end with the on- or off-load tap changer and at a second end with an indicator transmission. A setting indicator operatively connected with the indicator transmission displays the current setting of the on- or off-load tap changer, and a disengageable coupling is provided between the setting indicator and the load transmission.

Abstract: A method for voltage balancing series-connected power switching devices (IGBTs) each connected in parallel with a respective diverter having controllable impedance to controllably conduct current diverted from the associated power switching device, the method comprising the step of controlling each diverter to follow a series of at least two successively higher impedance states during an OFF period of the power switching devices. The series of impedance states for each diverter comprises a first impedance and then a second, higher impedance, the first impedance occurring in response to an indication of a start of the OFF period. The first impedance state preferably occurs during a tail current of the power switching device in parallel with the respective diverter and the second or later impedance state during a leakage current of that power switching device.

Abstract: A network node for a substation or a local network station has a control transformer with a primary side and a secondary side, an input line connected to the primary side, and an output line connected to the secondary side. A protective switch is provided in the input line or in the output line, and a sensor detects an electrical parameter in the input line or in the output line and generate a measurement signal. A controller coupled to the control transformer, to the protective switch, and to the sensor, serves to operate the control transformer in dependence on the measurement signal such that the control transformer has a predetermined transmission ratio and open the protective switch in dependence on the measurement signal as soon as the control transformer has the predetermined transmission ratio.

Abstract: A power switch driver for driving a control terminal of a power switch to drive a load, the power switch driver having a negative feedback circuit to control current delivered to the control terminal. The negative feedback circuit has a current output circuit having a current source and a current sink and serving for providing the current of the control terminal and configured to receive an output current control signal to control a magnitude of the current provided by the current output circuit, a terminal voltage input circuit for receiving a voltage from the control terminal and to output an indication of the voltage, an amplifier coupled to the terminal voltage input circuit for amplifying the terminal voltage indication to generate an amplifier output, and a reference voltage input circuit for receiving a reference voltage, having at least one resistor, and coupled to a charge supply input of the amplifier.

Abstract: An energy accumulator (15) for or in an on-load tap changer (10) comprises a motor (11) with an output shaft (12) and a load diverter switch (13) with an input shaft (14), comprising an elastic storage element (17); a transmission coupled to the storage element (17) and having an input hub (201) that can be rotationally fixed to the output shaft (12); an output hub (231) that can be rotationally fixed to the input shaft (14); and a variable transmission (20, 21) interposed between the input hub (201) and the storage element (17).

Abstract: Transformers are in a parallel circuit in which a tap changer with a control sensor is associated with each of the transformers and all control sensors are connected together by a communications connection. Each control sensor generates a measurement that is transferred by the communications connection. A measurement is generated with each of the control sensors, and at least one of the measurements of the control sensors of the transformers by the communications connection is transferred to N?1 control sensors. Then a controlling deviation caused by a circuit reactive current is calculated for each control sensor on the basis of the measurements of the control sensors. Finally the tap changer associated with each transformer is actuated by the respective control sensor as a function of the calculated controlling deviation such that minimization of the circuit reactive current is carried out for the respective transformer.

Abstract: In a method of changing an active winding number of a control winding in an electrical installation, the control winding is coupled to an alternating current mains having a predetermined period duration, the control winding being designed for a predetermined nominal current strength and includes a first and a second tap. Switching is effected, in accordance with a predetermined switching sequence plan from a first continuous current state to a second continuous current state, a load current flowing in the first continuous current state from the first tap to a load output line through a first main path with the second tap isolated from the load output line, the load current flowing in the second continuous current state from the second tap to the load output line through a second main path with the first tap isolated from the load output line.

Abstract: 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).

Abstract: 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.

Abstract: The invention relates to a switching arrangement (15) with a pre-selector (28) for a power transformer (10, 40) which has multiple windings (12, 14). The pre-selector is designed to optionally connect at least one first winding (12) to one of the two end contacts (30, 32) of at least one second winding (14). At least one first switch is arranged in the connection between the pre-selector (28) and the first winding (12), thereby allowing the pre-selector to be switched in an arc-free manner and thus in a gas-free manner as well.

Abstract: The invention relates to an on-load tap changer (2) according to the reactor switching principle for uninterrupted load switching between different tap windings of a tapped transformer (1), comprising: —an inductor (3) which is designed as an inductive transition reactance; —the inductor (3) being part of the on-load tap changer (2).

Abstract: An apparatus (1) for detecting gas (4) in a high-voltage device (3) filled with an insulating medium (2) comprises an inlet (5) for introducing a carrier gas (16) and an outlet (6) for discharging a carrier gas (16); at least one gas sensor (12) for detecting a gas (4); a first pump (9) for conveying the carrier gas (16) in the apparatus (1); a membrane (13) which at least consists of at least one semipermeable material, is at least partially surrounded by the insulating medium (2) and is at least partially subjected to a flow of the carrier gas (16); a second pump (10) for conveying the carrier gas (16) into the apparatus (1) and for conveying the carrier gas (16) out of the apparatus (1); wherein there is no valve which can be used to convey the carrier gas (16) into the apparatus (1) or out of the apparatus (1).

Abstract: A load selector has a load changeover switch insert with a switching tube rotatable about an axis, at least one switching segment fastened to the switching tube, and at least two vacuum interrupters in the at least one switching segment. Each vacuum interrupter has a switching tube having a respective axially movable contact that cooperates at its free end with an actuating lever. The vacuum interrupters are so arranged in alternation in opposite sense that the movable contacts of the at least two vacuum interrupters are movable with respect to the axis alternately in opposite directions.

Abstract: The invention relates to an electric motor-operated on-load tap changer (1) comprising an emergency drive. An electric motor (3) and a power store (13) of said on-load tap changer (1) are mechanically coupled by means of a gear (5) that is provided with a gear housing (90). The gear (5) comprises a gear shaft (61) on which a toothing (55) is designed. For manual emergency operation, the claimed gear shaft (61) has an extension (62) which comprises a free end (65) for attaching a tool (95). The invention also relates to a method for adjusting a defined switching position of an on-load tap changer (1) when in an emergency operation mode.

Abstract: The invention generally relates to power converters, and more particularly to a communications method for controlling at least one power switching device of a power converter, a communications system for a power converter, and a power converter comprising the communications system.

Abstract: The present invention generally relates to a switching cell for a phase leg of a power converter and a method of controlling a power converter to drive a load, and more particularly to a plurality of such switching cells, a phase arm for a power converter, a power converter phase leg, to a power converter for driving a load, and methods of making a power converter.

Abstract: The invention relates to a device (1) and a method for controlling the stability of a local network (3). The local network (3) comprises a plurality of outgoing circuits (41, 42, . . . , 4M,), each having at least one load (5) and/or at least one decentralized energy generation system (6). Said device is provided with an on-load tap-changer (14) for adjusting an output voltage of the local network transformer (10). The device is characterized in that a unit (16) for measuring current, connected to at least one of the plurality of outgoing circuits (41, 42, . . . , 4M,), and a unit (18) for measuring voltage, connected to a busbar (8) of the local network (3), are arranged in a transformer housing (20).

Abstract: The invention relates to a step switch, comprising a pre-selector and a fine selector. The invention is characterized in that the step switch has a connection (36) between the pre-selector and the fine selector (18), at least one coupling switch (38) being arranged in said connection. A pre-selector can be switched in a largely gas-free manner by means of said switchable connection with the aid of the fine selector.