Method and device for locating cable faults

摘要

The method is used for locating cable faults, in particular for locating cable faults which cannot be physically detected, in the region of branched cables. The pulse-reflection method is used and a capacitor is charged then subsequently discharged across a spark gap by spark-over at a fault location on the cable. In parallel with the main capacitor in an impulse-wave generator, a second pulse capacitor is discharged to the cable via a short-circuit switch. The resulting reflection wave is fed via an extraction coupling to a first channel of the digital memory. After opening of the short-circuit switch, the main capacitor in the impulse-wave generator and the second pulse capacitor are again charged and subsequently discharged again by closing the main switch on the faulty cable. The pulse capacitor is discharged via a plasma-triggered spark gap. The spark gap is triggered from the charge of the impulse-wave generator. By virtue of a time delay in the plasma formation, a discharge pulse of the pulse capacitor reaches the fault location in the cable after striking has already taken place. The reflection wave which results in this case without striking delay is fed via the extraction coupling to a second channel of the digital memory. The fault location is determined by means of evaluating deviations which occur between the two recordings. <IMAGE>