| 摘要 |
A device for sensing electric discharges in a test object 1 such as a cable joint with two electric connection conductors 1a, 1b, 1c, 1d, includes at least one of first and second sensors 2a, 2b and evaluation equipment EVU. Each one of the sensors generates and supplies to the evaluation equipment sensor signals v1, v2 in dependence on current pulses through the connection conductors and the direction thereof. The sensors are separated by a distance L1 corresponding to a time period for sensor signals originating from a current pulse passing through the cable joint. The evaluation equipment generates in dependence on the received sensor signals an indication signal IND, indicating an electric discharge in the test object. The evaluation equipment includes first and second tuning units T1, T2 respectively associated with the first and second sensors, each unit, in dependence on the respective sensor signal, forming a first filter signal SF1 and a second filter signal SF2, respectively, periodically oscillating with a preselected period TP, and a multiplier 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.
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