Abb Research Ltd.

Hitachi Energy Ltd

Abb Technology Ltd

Hitachi Energy Switzerland Ag

Abb Schweiz Ag

Kenneth Johansson

Peter Sjöberg

Udo Fromm

Thomas R Eriksson

Stefan G Johansson

Christer Tornkvist

Sture Lindahl

Björn Edberg

Christer T&ouml;rnkvist

Jan-Åke Börjesson

Robert Ståhl

Jens Kanje-nordberg

Gustaf Sandberg

Jan-ÅKe Borjesson

The present disclosure relates to a condenser core configured for surrounding an electrical conductor. The condenser core includes an insulation material and a plurality of electrically conducting capacitive layers for modifying electrical fields formed by a current flowing in the electrical conductor. At least one of the electrically conducting capacitive layers includes a first foil and a second foil. Each of the first and second foils of an outermost capacitive layer is connected with a grounding arrangement for grounding the foils.

Condenser core with grounded conductive foils in a capacitive layer

A protection device configured for being electrically connected to a test tap of a HV bushing for protecting the bushing from transient overvoltages. The protection device includes at least two parallel connected protection branches connected between the test tap and a ground connector configured for connecting to ground. Each of the protection branches includes a plurality of parallel connected gas discharge tubes, a Transient-Voltage-Suppression (TVS) diode connected in series with the gas discharge tubes, and a resistor connected in series with the gas discharge tubes and across the TVS diode.

Overvoltage protection for HV bushing test tap

A bushing including: a bushing comprising: a bushing body, an electrode contained in the bushing body, a flange body mounted to the bushing body, a tap assembly including: a hollow electrically conductive sleeve portion extending from the flange body, a conductor connected to the electrode and extending from the electrode into the sleeve portion, a pin connected to the conductor, an insulating body provided around the conductor in the sleeve portion, and an electrically conductive lid configured to be assembled with the sleeve portion, the lid having a cap portion and a hollow cylindrical extension portion, wherein the cap portion is configured to receive an end portion of the pin, wherein the extension portion extends axially from the cap portion and is configured to be received by the sleeve portion, and wherein the extension portion is configured to surround the insulating body in the sleeve portion when the lid is assembled with the sleeve portion.

Bushing with a tap assembly

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. At least during a predefined period immediately after actuation of the current interrupter unit a resonance current that has been generated by the first resonance circuit flows into the current interrupter unit from a different direction than a resonance current generated by the second resonance circuit would have, or vice versa.

Circuit breaking arrangement

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. An auxiliary power supply unit is coupled to the resonance circuit and adapted to selectively and controllably convey power to the at least one capacitor, thereby charging it. On a condition that voltage of the transmission line and/or voltage of the at least one capacitor does not comply with a selected voltage criterion, the auxiliary power supply unit is caused to convey power to the at least one capacitor. The circuit breaking arrangement may be arranged so as to allow for conveyance of power transmitted in the transmission line to the at least one capacitor, thereby charging it.

A lead-trough device for an electrical conductor, which structure includes an insulating body arranged for housing the electrical conductor along a central axis of the insulating body. Further, the lead-trough structure includes insulating layers and conducting layers arranged on the inside of the insulating body, which insulating layers and conducting layers are concentrically wrapped around the central axis of the body and alternatingly arranged along a transaxial direction of the insulating body. At least one conducting layer is wrapped concentrically around the central axis of the body for less than 360&#xb0; such that ends of the at least one conducting layer are spaced apart.

Bushings foil design

A high voltage AC transmission cable system for transmitting power between two points, each connected to one or more power networks, and a method to operate the system. At least one transformer is arranged at each end of the AC transmission cable, wherein at least one of the transformers is arranged to operate the transformer at a voltage whereby losses due to reactive power transport and dielectric losses are minimized. The AC cable is run at a variable voltage regulated such that the voltage is a function of the load for the transmission cable. This operating voltage is not necessarily the same as the nominal voltages in the connection points. A control and communication system and a graphical user interface for carrying out the method are also provided.

System for transmission of electric power

A device for sensing discharges in a test object (,) with two electric connection conductors (,), preferably a cable joint, comprises at least one first and one second sensor (,) and evaluation equipment (EVU). Each one of the sensors generates and supplies to the evaluation equipment sensor signals in dependence on current pulses through the connection conductors and the direction thereof, the first sensor a first sensor signal (v,) and the second sensor a second sensor signal (v,). The evaluation equipment generates in dependence on received sensor signals an indication signal (IND), indicating a partial discharge in the test object. The device comprises a first tuning unit (T,) associated with the first sensor and a second tuning unit (T,) associated with the second sensor, each unit, in dependence on the respective sensor signal, forming a first filter signal (SF,) and a second filter signal (SF,), respectively, periodically oscillating with a preselected period (TP), as well as a multiplying member (MU), which is supplied with, and in dependence on said filter signals, forms a product signal (SP), whereby the evaluation equipment forms the indication signal in dependence on the product signal.

Device for sensing partial discharges in test objects, preferably a cable joint

A method for space-charge measurement in a coaxial cable comprising an inner conductor (,), a cable screen (,) and an electric insulation (,) between the inner conductor and the cable screen, wherein the cable screen is removed on both sides of a measurement region, an electric voltage pulse is generated by an electric pulse generator (,) and is applied over part of the insulation (,) of the cable within the measurement range, an acoustic signal, in the presence of space charges in the cable insulation, is generated by the voltage pulse in cooperation with the space charges and a possible acoustic signal is recorded by a sound-recording device (,). A grounded annular outer electrode (,) is applied around the measurement region, the sound-recording device is arranged in direct contact with the annular outer electrode, the voltage pulse is applied to the cable screen on both sides of the measurement region and is connected, via the impedance of the cable, to the inner conductor of the cable.

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Täby, Sweden

Kenneth Johansson