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AssigneeABB Research Ltd.
InventorsTord Bengtsson, Lars-Gunnar Dahlberg, Thomas Eriksson, Akbar Kheirmand, Mats Leijon, Henry Siberg, Dick Rudolfsson, Dag Winkler
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A device for sensing electric discharges in a test object with at least two electric connection conductors comprises transducer equipment and evaluation equipment. The transducer equipment comprises at least one transducer for direction-sensitive sensing of current pulses through the connection conductors by sensing a magnetic field, generated by the current pulses, and the polarity thereof. The transducer delivers a transducer signal to the evaluation equipment in dependence on said current pulses and their direction. The evaluation equipment generates, in dependence on received transducer signals, an indicated signal indicating an electric discharge in the test object.
A device for sensing electric discharges in a current transformer arranged at a current-carrying conductor, the transformer having a secondary winding and a high-voltage bushing, in which bushing downwardly and upwardly extending parts of either of the current-carrying conductor and the secondary winding are arranged, the device comprising evaluation equipment and a Rogowski coil for delivery of a sensor signal to said evaluation equipment, wherein said Rogowski coil surrounds the downwardly and upwardly extending parts of either of the current-carrying conductor and the secondary winding, and said evaluation equipment in dependence on received sensor signals generates an indicating signal, indicating an electric discharge in the current transformer when the Rogowski coil senses current pulses which essentially simultaneously flow in the downwardly and upwardly extending parts of either of the current-carrying conductor and the secondary winding, either in a direction out of the current transformer or in a direction into the current transformer.
A device for sensing electric discharges in a test object with at least two electric connection conductors, the device comprising sensing equipment and an evaluation equipment, the sensing equipment having at least two sensors for direction-sensitive sensing of current pulses through the connection conductors by sensing a magnetic field generated by the current pulses and the polarity thereof, each of the sensors delivering a sensor signal to the evaluation equipment in dependence on the current pulses and their direction, the evaluation equipment generating an indicating signal, based on the received sensor signals, indicating an electric discharge in the test object when the sensing equipment senses current pulses which essentially simultaneously flow either in a direction out of the test object through all the connection conductors or in a direction into the test object through all the connection conductors, the evaluating equipment comprising means for forming a sum signal in dependence on a sum of sensor signals originating from sensors associated with mutually different connection conductors, means for forming a difference signal in dependence on a difference of sensor signals originating from sensors associated with mutually different connection conductors, and a comparing member for forming a comparison signal based on said sum signal and said difference signal and wherein the evaluation equipment forms the indicating signal based on said comparison signal.
Dependencies are inferred from the claim text.