Abstract: A transformer coil comprises low and high voltage windings wound on a supporting construction and immersed in a main insulation material. The transformer coil has also a first barrier arranged proximate the low voltage winding and a second barrier arranged proximate the high voltage winding. Each of the first and second barriers is gas-tight and semiconductive so that gas bubbles potentially released during immersion in the main insulation material are unable to migrate to a high electric field region during the casting process or during apparatus operation.

Abstract: A primary coil suitable for use in a transformer includes a primary winding bobbin onto which a layer of a primary winding and at least one layer, which includes a fixed number of 1 to 3 layers, of an interlayer insulation material are wound alternately, wherein the interlayer insulation material and the primary winding are impregnated with an epoxy, and wherein the interlayer insulation material is a nonwoven material or a crepe paper.

Abstract: A converter apparatus includes a string of electrically interconnected modules that includes a first group of modules comprising a first module and a second group of modules comprising a second module. A first screen is connected to a first defined electric potential and is located adjacent the first group of modules and a second screen is connected to a second defined electric potential and is located adjacent the second group of modules. During operation of the converter apparatus a resonance loop is created from the first module via the first and second screens and the second module back to the first module. A damping unit is located in the resonance loop and is set to dampen electromagnetic noise.

Abstract: A circuit breaker is connected between an input supply line and an output supply line of a low-voltage electrical system and comprises a test signal transceiver and evaluator. The test signal transceiver comprises a first transceiver section being capacitively or inductively coupled, at a first coupling point, with the input supply line, and a second transceiver section being inductively coupled, at a second coupling point, with the input or output supply line. One of the first and second transceiver section is a test signal transmitter configured to generate and inject an AC test signal into the input or output supply line, and the other one of the first and second transceiver section is a test signal receiver configured to receive the test signal from the input or output supply line. A test signal evaluator is configured to determine the state of the circuit breaker from the received test signal.

Abstract: A converter apparatus includes a string of electrically interconnected modules that includes a first group of modules comprising a first module and a second group of modules comprising a second module. A first screen is connected to a first defined electric potential and is located adjacent the first group of modules and a second screen is connected to a second defined electric potential and is located adjacent the second group of modules. During operation of the converter apparatus a resonance loop is created from the first module via the first and second screens and the second module back to the first module. A damping unit is located in the resonance loop and is set to dampen electromagnetic noise.

Abstract: Embodiments are generally based on employing a power transmission line in a HVDC link to provide auxiliary power to one of the ends of the HVDC link for facilitating a black start thereof when the HVDC link is de-energized, i.e. when at least one of the HVDC converter stations is de-energized and there is no transmission of power between inverter and rectifier HVDC converter stations on each side of the HVDC link. A relatively small amount of power can be conveyed towards one of the HVDC converter stations via the power transmission line so as to provide power to any auxiliary system(s) of the converter station, for example prior to a black start of the converter station being carried out.

Abstract: Embodiments are generally based on employing a power transmission line in a HVDC link to provide auxiliary power to one of the ends of the HVDC link for facilitating a black start thereof when the HVDC link is de-energized, i.e. when at least one of the HVDC converter stations is de-energized and there is no transmission of power between inverter and rectifier HVDC converter stations on each side of the HVDC link. A relatively small amount of power can be conveyed towards one of the HVDC converter stations via the power transmission line so as to provide power to any auxiliary system(s) of the converter station, for example prior to a black start of the converter station being carried out.

Abstract: A switching device is provided for disconnecting or connecting an electric machine, a converter or a plurality of electrical loads supplied with AC power from a power supply and controlled by a control unit. The switching device includes a current sink and at least one mechanical switch in the switching device are arranged in a circuit. The current sink is arranged, upon receipt of a signal, to close and sink the current, and the at least one mechanical switch is arranged to open and break the current on receipt of a signal to open supplied to the electric machine when the current load is at or close to zero. A method and a computer program for carrying out the method are described.

Abstract: The invention relates to a device for measuring the direct component of alternating current, applicable in current measuring systems where a low direct component of alternating current and a high amplitude of the alternating component of alternating current occur. The device for measuring the direct component of alternating current comprises a current-carrying wire (1) around which there is located a magnetic core (2) provided with a gap (3) in which a magnetic field sensor (4) with insulated terminals (5) is located and it comprises a shorted compensating winding (6) or (9) which is made in the form of a single turn coil placed on the core (2).

Abstract: A switching device is provided for disconnecting or connecting an electric machine, a converter or a plurality of electrical loads supplied with AC power from a power supply and controlled by a control unit. The switching device includes a current sink and at least one mechanical switch in the switching device are arranged in a circuit. The current sink is arranged, upon receipt of a signal, to close and sink the current, and the at least one mechanical switch is arranged to open and break the current on receipt of a signal to open supplied to the electric machine when the current load is at or close to zero. A method and a computer program for carrying out the method are described.

Abstract: A device for suppressing very fast transients, applicable in protecting electric and/or electric power equipment, and especially transformers operating in electric power substations and in wind power plants, connected in a supply network circuit downstream of a circuit breaker and upstream of the protected equipment is disclosed. The device is a component of an induction character, comprising a high-frequency magnetic core arranged around the current-conducting lead. On the magnetic core is wound at least one winding with at least one pair of terminals used for connecting at least one damping resistor. The inventive device contains an insulating body in which there is a magnetic core, a damping resistor and a winding, or an insulating body in which there is a magnetic core together with a damping resistor, a winding and a section of a current-conducting lead.

Abstract: The invention relates to a device for measuring the direct component of alternating current, applicable in current measuring systems where a low direct component of alternating current and a high amplitude of the alternating component of alternating current occur. The device for measuring the direct component of alternating current comprises a current-carrying wire (1) around which there is located a magnetic core (2) provided with a gap (3) in which a magnetic field sensor (4) with insulated terminals (5) is located and it comprises a shorted compensating winding (6) or (9) which is made in the form of a single turn coil placed on the core (2).

Abstract: The subject of the invention is a device for suppressing very fast transients (1, 1a, 1b), applicable in protecting electric and/or electric power equipment, and especially transformers operating in electric power substations and in wind power plants, connected in the supply network circuit downstream of the circuit breaker and upstream of the protected equipment. The device according to the invention is a component of an induction character (1, 1a, 1b), comprising a high-frequency magnetic core (2) arranged around the current-conducting lead (3). On the magnetic core (2) there is wound at least one winding (4, 4a) with at least one pair of terminals (6) used for connecting at least one damping resistor (7).

Abstract: The subject of the invention is a protection system for voltage transformers, finding application in the attenuation of ferroresonant states occurring in voltage transformers in high and medium voltage grids. The system according to the invention contains a ferroresonance detection circuit (3), connected to the terminals of the secondary winding of the voltage transformer (2) and in parallel with a damping circuit (4), containing a switching means (6) connected in series with a damping burden (7). The system according to the invention contains a control block (5) connected to the switching means (6), characterised by that the control block (5) contains a PWM (Pulse Width Modulation) generator.

Abstract: An arrangement is disclosed for supplying power to a field device used to monitor an industrial process in a plant, having an enclosure and a wireless communications interface for data communications with a central data-processing device, and having a thermoelectric converter, which converts an existing heat flow between two points at different temperatures into electrical power and supplies this power to the field device. The thermoelectric converter is arranged in a separate enclosure from the field device, and transfers the electrical power to the field device by means of electrical wires or wireless transmission.

Abstract: A device, located in a vessel having an inlet and at least one outlet, through which a mixture of fluids flows, for promoting electrostatic coalescence of a first conductive fluid emulsified in a second fluid. The device includes a number of tubular electrostatic coalescer elements extending in the flow direction which are arranged in a matrix arranged over the cross sectional area of the vessel, and an applicator operative to apply an electrical field to the fluids flowing through the coalescer elements.

Abstract: The subject of the invention is a device for suppressing high frequency current or/and voltage components, applicable in protecting electrical equipment, especially against the effects of overvoltage in electrical power networks and stations. The inventive device is characterised in that it contains a series impedance element which is at least one magnetic core reactor (1, 2) whose magnetic circuit comprises at least two active parts on which the reactor windings (3, 4) are wound, which are connected with each other in series and anti-parallel.

Abstract: A protection system for a transformer system that includes three single phase transformers with auxiliary secondary windings, respectively. The auxiliary secondary windings are connected to form an open delta configuration. The protection system is connected into the open delta configuration, between the auxiliary secondary windings of two of the transformers. The protection system includes a circuit having an element with a threshold voltage and current characteristic connected in series with a thermal protection device and a resistor.

Abstract: An electrically energized device for coalescing a first conductive fluid emulsified in a second fluid. A tube member has at least one fluid inlet and at least one fluid outlet. The tube member defines a flow channel for an emulsion of the first and second fluid from its inlet side to its outlet side and includes at least one electrically insulating wall portion. An interacting pair of a first and a second electrode is separated from the first and second fluid by at least one insulating wall portion of the tube member. The electrodes are supplied with a voltage for the purpose of subjecting the first and second fluid flowing through the flow channel to an electrostatic field. At least one passive center electrode is made of a conducting material and is arranged in the channel and electrically insulated from the first and second electrode.

Abstract: An arrangement is disclosed for supplying power to a field device used to monitor an industrial process in a plant, having an enclosure and a wireless communications interface for data communications with a central data-processing device, and having a thermoelectric converter, which converts an existing heat flow between two points at different temperatures into electrical power and supplies this power to the field device. The thermoelectric converter is arranged in a separate enclosure from the field device, and transfers the electrical power to the field device by means of electrical wires or wireless transmission.