Abstract: Methods and devices for locating partial discharges in electric cables with a high-voltage source coupled to the cable to be tested, a decoupling unit connected to an end of the cable and a data-processing system that is connected via a sensor unit to the decoupling unit and that detects a partial discharge or partial discharges when they exist from the sensor signals. The methods and devices particularly distinguish themselves by a short evaluation duration for the locating process. This is done by detecting events, parameterizing the events identified as pulses, formation of pairs of the events identified as pulses and parameterized, classification of the event pairs, assignment of a partial discharge from the classification and determination of the location of the partial discharge(s) from the different in transit times between the respective partial discharge and its accompanying reflection.

Abstract: The invention relates to methods and devices for locating partial discharges in electric cables with a high-voltage source coupled to the cable to be tested, a decoupling unit connected to an end of the cable and a data-processing system that is connected via a sensor unit to the decoupling unit and that detects a partial discharge or partial discharges when they exist from the sensor signals. The methods and devices particularly distinguish themselves by a short evaluation duration for the locating process. This is done by detecting events, parameterizing the events identified as pulses, formation of pairs of the events identified as pulses and parameterized, classification of the event pairs, assignment of a partial discharge from the classification and determination of the location of the partial discharge(s) from the different in transit times between the respective partial discharge and its accompanying reflection.

Abstract: A method and an apparatus are provided to reduce or eliminate interference signals that have been additively superimposed on a useful signal for locating a cable sheathing fault of a buried electrical cable. A correction unit includes a filter, a delay device and/or a DC component estimator. The correction unit automatically determines a transient interference signal and a DC offset voltage component that have been superimposed on the useful signal as received in an input signal of the correction unit, and then subtracts these determined interference signals from the input signal to provide the interference-free or interference-suppressed useful signal as the output.

Abstract: An apparatus including a portable receiver with an acoustic sensor and a magnetic field sensor is adapted for locating a fault in an underground electrical line by evaluating ground-borne acoustic signals and electromagnetic signals emitted from a succession of sparking arc-overs caused at the fault location by voltage pulses fed into the electrical line. The apparatus further includes an arrangement for eliminating interference noises from the acoustic signals, wherein the acoustic received signals are delivered to and stored in a memory, and then a respective acoustic signal is processed with reference to or in combination with a previous stored acoustic signal by a processing algorithm in a processing unit so as to reduce or suppress the acoustic interference noises in the acoustic signals. Start time points of the individual acoustic signals are synchronized with reference to associated electromagnetic signals. A result of the processing algorithm is supplied to an evaluating unit.

Abstract: A method and an apparatus are provided to reduce or eliminate interference signals that have been additively superimposed on a useful signal for locating a cable sheathing fault of a buried electrical cable. A correction unit includes a filter, a delay device and/or a DC component estimator. The correction unit automatically determines a transient interference signal and a DC offset voltage component that have been superimposed on the useful signal as received in an input signal of the correction unit, and then subtracts these determined interference signals from the input signal to provide the interference-free or interference-suppressed useful signal as the output.

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.

Abstract: An apparatus including a portable receiver with an acoustic sensor and a magnetic field sensor is adapted for locating a fault in an underground electrical line by evaluating ground-borne acoustic signals and electromagnetic signals emitted from a succession of sparking arc-overs caused at the fault location by voltage pulses fed into the electrical line. The apparatus further includes an arrangement for eliminating interference noises from the acoustic signals, wherein the acoustic received signals are delivered to and stored in a memory, and then a respective acoustic signal is processed with reference to a previous stored acoustic signal by a processing algorithm in a processing unit. Start time points of the individual acoustic signals are synchronized with reference to associated electromagnetic signals. A result of the processing algorithm is supplied to an evaluating unit.

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.