US 8,474,320 B2Granted

Method and apparatus for locating cable faults

AssigneesHagenuk KMT Kabelmesstechnik GmbH, Technische Universitaet Dresden

InventorsUlrich Kordon, Steffen Kuerbis, Matthias Wolff, Marco Kuettner, Marco Stephan, Torsten Berth

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Abstract

An electrical pulse fed into an electrical cable, e.g. a power transmission or distribution cable buried underground, produces an acoustic signal, e.g. an arc-over or discharge noise, at a fault in the cable. This acoustic signal is detected and used to locate the fault. But the acoustic signal has interference noise superimposed on it, which makes it difficult to identify the acoustic signal in the noise-burdened received signal, and thus also makes it difficult or impossible to accurately locate the fault. To minimize or avoid the influence of interference noises, the relevant acoustic signal is identified in the received signal by comparing the received signal with predetermined sample data, such as signal patterns, characteristics or characteristic sets.

Claims18

Dependent claims

A method of locating a fault at a fault location in an electrical cable that is for electrical power transmission or distribution, wherein at least the fault location of the cable is covered by a cover medium, and wherein said method comprises:

a) emitting an original acoustic signal from said fault, and allowing said original acoustic signal to propagate through said cover medium from said fault location to a detection location;
b) using an acoustic sensor at said detection location, detecting a received signal that includes said original acoustic signal;
c) comparing said received signal or a pre-processed version thereof with sample data stored in a memory, wherein said sample data comprises at least one sample data item selected from the group consisting of signal patterns, signal characteristics, signal characteristic sets, signal amplitudes, signal frequencies, signal feature sequences, signal heuristic models, signal sections, and complete signals of previously determined acoustic sample signals representative of acoustic signals emitted from sample faults in one or more sample cables;
d) based on said comparing, determining that a portion of said received signal has a correspondence or at least a predetermined similarity to at least one said sample data item of said sample data, and thereby identifying said portion as said original acoustic signal included in said received signal;
and
e) using at least information obtained from said portion of said received signal to enable said locating of said fault.

3 more elements

An apparatus for locating a fault at a fault location in an electrical cable that is for electrical power transmission or distribution, wherein at least the fault location of the cable is covered by a cover medium, and wherein said apparatus comprises:

an acoustic sensor configured to be arranged at a detection location and to detect an acoustic received signal that includes an original acoustic signal emitted from the fault and propagated through the cover medium to the detection location;
a memory storing sample data which comprises at least one sample data item selected from the group consisting of signal patterns, signal characteristics, signal characteristic sets, signal amplitudes, signal frequencies, signal feature sequences, signal heuristic models, signal sections, and complete signals of previously determined acoustic sample signals representative of acoustic signals emitted from sample faults in one or more sample cables;
and
a comparison unit connected to said acoustic sensor and to said memory, wherein said comparison unit is configured to compare the received signal or a pre-processed version thereof with the sample data, and is configured to determine that a portion of the received signal has a correspondence or at least a predetermined similarity to at least one sample data item of the sample data and thereby to identify the portion as the original acoustic signal included in the received signal.

1 more element

Dependencies are inferred from the claim text.