Abstract: A modular multilevel converter includes a plurality of submodules, each having at least two electronic switching elements, an electric energy store, two submodule connections, a bypass switch bridging the submodule, and a communication element communicating with a communication apparatus. A method for operating the modular multilevel converter includes ascertaining that the submodules have a defective submodule so that the communication element in the defective submodule does not communicate with the communication apparatus, determining whether a present arm current resulting from an operating point of the modular multilevel converter is below a predetermined threshold value, and generating or amplifying a converter-internal circular current with the defective submodule if the arm current resulting from the operating point is below the predetermined threshold value. A modular multilevel converter is also provided.

Abstract: A converter has module devices each with a series connection of at least two partial modules being electrically connected in series. A central device is configured to switch module control devices, in which a sum of the transmitted voltage values or the transmitted sum value reaches a predefined voltage threshold, into a second charging phase of a charging operation by transmitting a first voltage specification relating to switched-off partial modules and a second voltage specification relating to switched-on partial modules to the module control devices. The module devices are configured to meet the first and second voltage specifications by setting none, one or more of the communication-capable partial modules thereof into a switched-on operating state and none, one or more of the other communication-capable partial modules thereof into a switched-off operating state, and to continue the charging of the energy stores which are in the switched-on and blocked operating state.

Abstract: A modular multilevel converter includes a plurality of submodules, each having at least two electronic switching elements, an electric energy store, two submodule connections, a bypass switch bridging the submodule, and a communication element communicating with a communication apparatus. A method for operating the modular multilevel converter includes ascertaining that the submodules have a defective submodule so that the communication element in the defective submodule does not communicate with the communication apparatus, determining whether a present arm current resulting from an operating point of the modular multilevel converter is below a predetermined threshold value, and generating or amplifying a converter-internal circular current with the defective submodule if the arm current resulting from the operating point is below the predetermined threshold value. A modular multilevel converter is also provided.

Abstract: A method manages a fault on a DC voltage side of a converter assembly including a modular multistage converter with switching modules having semiconductor switches and an energy store. Some switching modules are a first type and others are a second type. During operation, a positive switching module voltage, negative switching module voltage or zero voltage are generated at terminals of switching modules of the first type, and a positive switching module voltage or zero voltage are generated at terminals of switching modules of the second type. Upon detecting a DC voltage side fault, switching modules of the first type are actuated such that the polarity of their energy store voltages corresponds to the polarity of a fault current, and energy stores of switching modules of the first type are charged to a voltage exceeding their rated voltage. A converter assembly carrying out the method is also provided.

Abstract: A current converter unit for a high-voltage direct-current (HVDC) transmission contains a first converter and a second converter. A first direct-current terminal of the first converter is connected to a first conductor terminal point for a first HVDC transmission conductor. A second direct-current terminal of the first converter is connected to a first direct-current terminal of the second converter such that a connection point is formed. A second direct-current terminal of the second converter is connected to a second conductor terminal point for a second HVDC transmission conductor. The connection point is connected to ground potential by a current-damping electric component, and the connection point is connected to the ground potential by a direct-current switch.

Abstract: A current converter unit for a high-voltage direct-current (HVDC) transmission contains a first converter and a second converter. A first direct-current terminal of the first converter is connected to a first conductor terminal point for a first HVDC transmission conductor. A second direct-current terminal of the first converter is connected to a first direct-current terminal of the second converter such that a connection point is formed. A second direct-current terminal of the second converter is connected to a second conductor terminal point for a second HVDC transmission conductor. The connection point is connected to ground potential by a current-damping electric component, and the connection point is connected to the ground potential by a direct-current switch.

Abstract: A method manages a fault on a DC voltage side of a converter assembly including a modular multistage converter with switching modules having semiconductor switches and an energy store. Some switching modules are a first type and others are a second type. During operation, a positive switching module voltage, negative switching module voltage or zero voltage are generated at terminals of switching modules of the first type, and a positive switching module voltage or zero voltage are generated at terminals of switching modules of the second type. Upon detecting a DC voltage side fault, switching modules of the first type are actuated such that the polarity of their energy store voltages corresponds to the polarity of a fault current, and energy stores of switching modules of the first type are charged to a voltage exceeding their rated voltage. A converter assembly carrying out the method is also provided.

Abstract: A modular multilevel converter has a plurality of sub-modules, each of which includes at least two electronic switching elements and an electrical energy storage device. The sub-modules are controlled by a control device. An optical output of the control device of the converter is connected to an input of an optical distributor by way of a first optical waveguide. A plurality of outputs of the optical distributor are individually connected to an optical input of one of the sub-modules, respectively, by way of a second optical waveguide.

Abstract: A converter station for the transmission of electrical power has a diode rectifier with a DC terminal and an AC terminal. At least one transformer is connected to the AC terminal. In order to render the converter station as compact as possible, the diode rectifier is arranged in an insulating material.

Abstract: A device controls a load flow in an alternating-voltage network. The device is distinguished by a module series circuit of two-pole switching modules that can be inserted in series into a phase line of the alternating-voltage network. Each switching module has an energy store and controllable power semiconductors that can be switched on an off and each switching module can be controlled in such a way that a switching-module voltage can be produced at the poles thereof, which switching-module voltage corresponds to a positive or negative energy-store voltage or a voltage having the value of zero. A control apparatus for controlling the switching modules is provided, which control apparatus is configured to control the switching modules in such a way that a periodic longitudinal voltage can be produced at the module series circuit. A method for controlling a load flow in an alternating-voltage network is performed by the device.

Abstract: A modular multilevel converter includes a plurality of sub-modules. Each of the sub modules has at least two electronic switching elements, an electrical energy storage device, two galvanic power terminals, an optical communication input (222) and an optical communication output. A plurality of the sub-modules is connected to a series circuit by way of their communication input and communication output.

Abstract: A device for switching a direct current includes an operating current path which has a mechanical switch, a switch-off current path which is connected in parallel to the operating current path and has a power-electronic switch, and a commutation device which allows commutation of the direct current from the operating current path into the switch-off current path. The commutation device includes a transformer.

Abstract: A commutating circuit for an electronic power converter has a first switching device, by which the electronic power converter can be electrically bridged, and a circuit part for limiting the size of the time-related voltage change of a voltage present on the first switching device. The circuit part limits the time-related voltage variation.

Abstract: A measuring device measures an electrical current and contains a light source for generating a polarized primary light signal for feeding into a Faraday sensor unit, and a detector for detecting a secondary light signal provided by the Faraday sensor unit and polarization-altered in relation to the primary light signal. An optical-electrical compensation element, by which the polarization alteration of the secondary light signal can be compensated via an opposite polarization alteration, and a measurement signal, according to the opposite polarization alteration, for the electrical current can be deduced. A method for measuring an electrical current by use of the measuring device is further disclosed.

Abstract: An apparatus switches a direct current in a high-voltage line. The apparatus contains a multiplicity of switching units, which are arranged so as to form a series circuit in the high-voltage line. Each switching unit in this case contains a switching element and a surge arrester arranged in a parallel circuit with the switching element, the threshold voltage of the surge arrester being higher than a rated voltage of the switching element. A sum of the rated voltages of the switching elements corresponds at least to an operating voltage of the high-voltage line. The switching elements are mechanical switches, and each mechanical switch contains a contact arrangement having two disconnectable contact pieces and is configured to build up an arcing voltage on disconnection of the contact pieces with a magnitude which is higher than the rated voltage of the mechanical switch.

Abstract: A modular multilevel converter has a plurality of sub-modules, each of which includes at least two electronic switching elements and an electrical energy storage device. The sub-modules are controlled by a control device. An optical output of the control device of the converter is connected to an input of an optical distributor by way of a first optical waveguide. A plurality of outputs of the optical distributor are individually connected to an optical input of one of the sub-modules, respectively, by way of a second optical waveguide.

Abstract: A modular multilevel converter includes a plurality of sub-modules. Each of the sub modules has at least two electronic switching elements, an electrical energy storage device, two galvanic power terminals, an optical communication input (222) and an optical communication output. A plurality of the sub-modules is connected to a series circuit by way of their communication input and communication output.

Abstract: A device controls a load flow in an alternating-voltage network. The device is distinguished by a module series circuit of two-pole switching modules that can be inserted in series into a phase line of the alternating-voltage network. Each switching module has an energy store and controllable power semiconductors that can be switched on an off and each switching module can be controlled in such a way that a switching-module voltage can be produced at the poles thereof, which switching-module voltage corresponds to a positive or negative energy-store voltage or a voltage having the value of zero. A control apparatus for controlling the switching modules is provided, which control apparatus is configured to control the switching modules in such a way that a periodic longitudinal voltage can be produced at the module series circuit. A method for controlling a load flow in an alternating-voltage network is performed by the device.

Abstract: An actuating device for a vacuum switching tube has a connecting element which can be connected to an electric contact of the vacuum switching tube, an electromagnetic actuating device for displacing the connecting element between a first and a second position, and a retaining yoke, relative to which the connecting element can be displaced and has a first magnetic element. The first magnetic element generates a first and a second magnetic circuit in the retaining yoke. The actuating device further has a ferromagnetic retaining anchor, which is arranged on the connecting element. The retaining anchor is located in the first position of the connecting element in the first magnetic circuit and in the second position of the connecting element in the second magnetic circuit. The connecting element is held in the first and in the second position by a respective magnetic force between the retaining yoke and the retaining anchor.

Abstract: A converter station for the transmission of electrical power has a diode rectifier with a DC terminal and an AC terminal. At least one transformer is connected to the AC terminal. In order to render the converter station as compact as possible, the diode rectifier is arranged in an insulating material.