Abstract: A method and computer program product are provided for selecting switching cells for voltage contribution in a phase arm of a multilevel converter, a cell selecting control device for a multilevel converter and a multilevel converter. The cell selecting control device and multilevel converter includes a balancing control element that obtains a reference voltage for the phase arm, obtains a measurement of the current running through the phase arm and selects cells for contributing to an AC voltage output from the multilevel converter based on the reference voltage and the magnitude of the phase arm current.

Abstract: It is provided a mechanical bypass switch device arranged to bypass a converter cell in a power converter. The mechanical bypass switch device includes: a mechanical switch; a mechanical switch actuator arranged to make the mechanical switch conduct when supplied with an electric signal; a first control input; and a second control input. The mechanical bypass switch device is arranged such that a control signal, provided on either one of the first control input and the second control input or on both of the first control input and the second control input, causes the mechanical switch to conduct. A corresponding converter arm and bypass converter are also presented.

Abstract: A short-circuiting arrangement for capacitors of a high voltage converter are provided, the capacitors each having two connection terminals, the arrangement including a short-circuiting wire configured to be moved along while in sliding contact with the connection terminals and including a short-circuiting section with electrically conductive material connected to a ground potential and a probing section with electrically conductive material and a voltage evaluating unit electrically connected to the short-circuit section and the probing section and configured to detect, as the probing section and short-circuiting section are connected to the respective connection terminals, the voltage across the capacitor, compare the voltage with a discharge threshold and halt or move the short-circuiting wire based on the detected voltage.

Abstract: A method and device are disclosed for supervising the operation of plural current transformers and for prevention of a malfunction, such as false tripping of power in an electrical system. Exemplary embodiments can include measuring current parameters (e.g., magnitude and phase angle) for each winding in current transformer (CT) sets. A negative sequence current can be calculated from measured phase currents and a fault condition determined. A phase angle difference parameter derived from phase measurements between two healthy CTs can be used as an additional condition parameter for reliable operation of equipment in the electrical system.

Abstract: A transmission system includes an electrical conductor and an insulation layer circumferentially covering the conductor. The layer includes at least two layer sections including a plurality of sublayers concentrically orientated, whereby each sublayer comprises one or more strips arranged beside each other in a circumferential direction. Gaps are formed between adjacent edges of strips and each gap is covered by a strip of an adjacent sublayer. Each of the strips includes one or more sheets arranged beside each other in a radial direction. Each sheet includes an insulation material including cellulose paper and polymer. At least one sublayer includes at least one sheet of said cellulose paper, and at least one sublayer including at least one sheet of said polymer, and whereby the insulation layer is impregnated.

Abstract: A filter apparatus includes at least one filter, each filter being tunable and including at least one capacitor arrangement. The capacitor arrangement includes a plurality of first capacitors, a plurality of second capacitors, and a plurality of switches. Each switch is switchable between a non-conducting mode and a conducting mode. The plurality of second capacitors and the plurality of switches are arranged to connect or disconnect the second capacitors on different potentials in order to tune the filter by adjusting the capacitance of the filter. An electrical power transmission or distribution system includes such a filter apparatus. A method is provided for filtering harmonics in an electrical power transmission or distribution system by means of such a filter apparatus.

Abstract: A circuit breaking arrangement is disclosed, which is adapted to be coupled to a transmission line arranged to carry direct current for controllably effecting discontinuation of flow of direct current in the transmission line. The circuit breaking arrangement includes a current interrupter unit adapted to, when actuated, interrupt current in the transmission line and a first resonance circuit and at least a second resonance circuit. Each of the first and the at least a second resonance circuit is adapted to, upon actuation of the current interrupter unit and when the respective resonance circuit is activated, generate a resonance current superposing current of any arc generated in the current interrupter unit after actuation thereof.

Abstract: The invention relates to a method, searching arrangement and a computer program product for searching for process control objects in a process control system (10). A searching unit (22; 38) providing a search function receives, from a user, a first search term regarding process control objects in the process control system, obtains the position of the user in the process control system, searches for process control objects using the first search term, and presents the results of the search, where the presented results depend on the user position.

Abstract: A voltage source converter includes a black start control unit and cells, where each cell includes a first switch between a first end of a cell capacitor and a first cell terminal, a second switch between a second end of the cell capacitor and the first cell terminal, where a second cell terminal is provided via the first or the second end of the cell capacitor, a first power supply unit and a second power supply unit, where the black start control unit is configured to perform, after the initial application of a DC voltage to a cell terminal of a cell and the subsequent initial charging of the chargeable power supply unit of one of the switches, charging of an uncharged power supply unit of the other switch through repeatedly turning on and off the switch with initially charged power supply unit.

Abstract: A circuit breaking arrangement is disclosed, which is adapted to be coupled to a transmission line arranged to carry direct current for controllably effecting discontinuation of flow of direct current in the transmission line. The circuit breaking arrangement includes a current interrupter unit, which is adapted to, when actuated, interrupt current in the transmission line, and at least one resonance circuit. The resonance circuit is connected in parallel with the current interrupter unit and includes at least one capacitor, at least one inductor and at least one switch element. The resonance circuit is adapted to, upon actuation of the current interrupter unit, generate a resonance current superposing current of any arc generated in the current interrupter unit after actuation thereof, upon closing of the switch element by means of successive discharging and charging of the at least one capacitor.

Abstract: A circuit breaker including a first and a second contact movable relative each other between an open position, in which the contacts are at a distance from each other, and a closed position, in which the contacts are in electrical contact with each other. The first contact includes one or more contact elements adapted to be in electrical contact with the second contact when the contacts are in the closed position, and a mesh made of metal arranged in thermal contact with the contact elements. The mesh is arranged to at least partly surround the contact elements to allow heat to conduct from the contact elements to the mesh.

Abstract: An arrangement for controlling the electric power transmission in a high voltage direct current, HVDC, power transmission system includes at least one HVDC transmission or distribution line for carrying direct current, DC, and the arrangement includes an apparatus connectable to the HVDC transmission or distribution line, the apparatus being arranged to control the direct current of the HVDC transmission or distribution line by introducing a DC voltage in series with the HVDC transmission or distribution line. The arrangement includes a protection device for protecting the apparatus against over-current or overvoltage occurrences. The protection device includes a bypass device connectable to the HVDC transmission or distribution line and connected in parallel with the apparatus. The bypass device is arranged to be in a non-conducting mode and arranged to be set to a conducting mode.

Abstract: A method for controlling a first and a second reverse-conducting insulated gate bipolar transistor (RC-IGBT), electrically connected in series, is disclosed. A collector of the first RC-IGBT is electrically connected to a positive pole of a direct current voltage source, and an emitter of the second RC-IGBT is electrically connected to a negative pole of the DC voltage source. Further, an emitter of the first RC-IGBT is electrically connected to a collector of the second RC-IGBT to form an alternating current terminal. A gate voltage is applied to respective gates of the first and second RC-IGBTs, wherein the gate voltage is controlled based on a magnitude and a direction of an output current on the AC terminal and on a command signal alternating between a first and a second value.

Abstract: It is presented a converter cell (10a; 10b) arranged to be used in a high voltage multilevel converter. The converter cell comprises: an energy storage element (16a; 16b) and a plurality of switching elements (S1, . . . , S8). The plurality of switching elements comprises at least one thyristor (S3; S8) and a plurality of transistors (S1, S2, S4; S5, S6, S7). Each one of the at least one thyristor (S3; S8) is provided in a position for a switching element in the converter cell where, during normal operation of the converter cell, the at least one thyristor is in a continuous conducting state. This reduces the power losses of the converter cell. A corresponding multilevel converter and a method are also presented.

Abstract: A device for indicating the state of an electrical switching apparatus includes a movable contact arranged movable between a first and a second position. The device includes at least one protruding contact element arranged on the movable contact, at least one contact pin arranged in the close vicinity to the movable contact such that said contact element abuts the contact pin when the movable contact is in the first position and said contact element is at a distance from the contact pin when the movable contact is in the second position. The contact element and the contact pin form an electrical switch and a detector arrangement configured to detect when said electrical switch is closed and by that detect when the movable contact is in the first position.

Abstract: A vacuum interrupter is disclosed with a fixed contact and a movable contact placed axially in a spaced apart relationship. The ceramic insulator cylinders each surround the fixed contact and the movable contact. A floating shield within the ceramic cylinders has a floating potential flange disposed between the two ceramic cylinders, and exposed to external ambient. Encapsulation for at least one contact terminal extends from a metallic end cap of the corresponding contacts to cover a respective ceramic cylinder by an overlapping distance.

Abstract: A tubular electrical insulation device for a cable is arranged for receiving a plurality of electrical conductors segments by insertion. The insulation device is flexible and includes an inner circumferential electrically conductive layer for establishing an electric contact to the electrical conductors once inserted into the tubular electrical insulation device. A high voltage power cable arrangement includes a plurality of elongated electrical conductor segments arranged to be placed alongside one another and in electrical contact to one another to form an inner electrical conductor of a high voltage power cable, and an elongated tubular electrical insulation device arranged to house and surround the inner electrical conductor. A method for providing a flexible insulated high voltage power cable includes the step of assembling a plurality of elongated electrical conductor segments and an electrical insulation device on site to form the cable.

Abstract: A method, field user presenting arrangement and a computer program product for enabling an operator of a process control system to determine the location of field users in the process control system are provided. The arrangement includes a presentation control unit that obtains position data of the position of a field user, obtain the positions of objects in the process control system, compares the position of the field user with the positions of the objects, determines that the field user is in the vicinity of an object if the distance between the position of the field user and the position of the object is below a proximity threshold, and presents the field user on graphics depicting the process, where a field user deemed to be in the vicinity of an object is presented at this object in the graphics.

Abstract: The present disclosure relates to a method for facilitating monitoring and control of an industrial process by means of a portable device comprising a projector arranged to project process graphics associated with process components of the industrial process. The method comprises a) obtaining, by means of the portable device, process component identification data of a process component; b) obtaining distance data for determining a distance between the portable device and the process component; and c) obtaining a process graphics image based on the process component identification data and the distance data for projection by the portable device, wherein the process graphics image is associated with a portion of the industrial process comprising the process component, and wherein information contained in the process graphics image is based on the distance between the portable device and the process component. The present disclosure further relates to a computer program and to a portable device.

Abstract: A multilevel converter converting between AC and DC includes a phase arm with a number of cells between a DC pole and an AC terminal, the cells include at least one hybrid full bridge cell including a first cell connection terminal for coupling to the DC pole, a second cell connection terminal for coupling to the AC terminal, an energy storage element having a positive and a negative end, a first group of series connected semiconducting units in parallel with the energy storage element, where a junction between these forms one cell connection terminal, and a second group of series connected semiconducting units in parallel with the energy storage element and including a third semiconducting unit and a fourth semiconducting unit consisting of a number of unidirectional conducting elements including at least one unidirectional conducting element, where a junction between these forms a further cell connection terminal.