Method and device for identifying and locating cyclic momentary insulation faults in an underground power supply system

Patent metadata

Field	Value
Publication number	US-11867718-B2
Application number	US-202217972644-A
Country	US
Kind code	B2
Filing date	Oct 25, 2022
Priority date	Oct 26, 2021
Publication date	Jan 9, 2024
Grant date	Jan 9, 2024

Abstract

The invention relates to a method and a device for identifying and locating cyclic momentary insulation faults in an ungrounded power supply system, the method comprising the steps: detecting a fault current caused by the momentary insulation fault as a differential current in the branch circuit to be monitored and displaying the temporal progression of the differential current via a differential current signal by means of a differential current sensor; providing a processing signal which temporally describes a process sequence of a process taking place in the consumer; correlating the differential current signal with the processing signal in a computing unit in order to yield a correlation signal as a measure for a temporal match between the differential current signal and the processing signal; signaling the momentary insulation fault via the computing unit by means of a signaling signal if the correlation signal shows the temporal match. The device according to the invention has a differential current sensor and a computing unit so that it can implement the method according to the invention.

First claim

The invention claimed is:

1. A method for identifying and locating cyclic momentary insulation faults in an ungrounded power supply system having a consumer connected via a branch circuit, the method comprising the steps:
detecting a fault current caused by the momentary insulation fault as a differential current in the branch circuit being monitored and displaying the temporal progression of the differential current via a differential current signal by means of a differential current sensor,
providing a processing signal which temporally describes a process sequence of a process taking place in the consumer,
correlating the differential current signal with the processing signal in a computing unit in order to yield a correlation signal as a measure for a temporal match between the differential current signal and the processing signal, and
signaling the momentary insulation fault via the computing unit by means of a signaling signal if the correlation signal shows the temporal match.

2. The method according to claim 1 , further including
generating the processing signal by means of a sensor device by detecting a process parameter related to the process and by displaying the temporal progression of the process parameter.

3. The method according to claim 2 , further including
detecting as a process parameter a physical variable describing the process sequence or a variable derived therefrom.

4. The method according to claim 3 , further including
correlating as a process signal a control signal leading the process sequence.

5. The method according to claim 4 , further including
detecting, by means of a voltage measuring device, between an active conductor of the underground power supply system and ground, the temporal progression of a displacement voltage as a residual voltage signal and correlating with the differential current signal in the computing unit.

6. The method according to claim 1 , further including
correlating as a process signal a control signal leading the process sequence.

7. The method according to claim 2 , further including
correlating as a process signal a control signal leading the process sequence.

8. The method according to claim 1 , further including
detecting, by means of a voltage measuring device, between an active conductor of the underground power supply system and ground, the temporal progression of a displacement voltage as a residual voltage signal and correlating with the differential current signal in the computing unit.

9. The method according to claim 2 , further including
detecting, by means of a voltage measuring device, between an active conductor of the underground power supply system and ground, the temporal progression of a displacement voltage as a residual voltage signal and correlating with the differential current signal in the computing unit.

10. The method according to claim 3 , further including
detecting, by means of a voltage measuring device, between an active conductor of the underground power supply system and ground, the temporal progression of a displacement voltage as a residual voltage signal and correlating with the differential current signal in the computing unit.

11. A device configured for identifying and locating cyclic momentary insulation faults in an ungrounded power supply system having a consumer connected via a branch circuit, comprising
a differential current sensor configured for detecting a fault current caused by the momentary insulation fault as a differential current in the branch circuit being monitored and displaying the temporal progression of the differential current via a differential current signal,
a computing unit configured for (a) receiving a processing signal which temporally describes a process sequence of a process taking place in the consumer, (b) correlating the differential current signal with the processing signal in order to yield a correlation signal as a measure for a temporal match between the differential current signal and the processing signal, and (c) signaling a momentary insulation fault by means of a signaling signal if the correlation signal shows the temporal match.

12. The device according to claim 11 , further including
a sensor device configured to generate the processing signal by detecting a process parameter related to the process and by displaying the temporal progression of the process parameter.

13. The device according to claim 12 , wherein
the sensor device is configured for detecting a physical variable describing the process sequence or a variable derived therefrom as a process parameter.

14. The device according to claim 13 , wherein
the processing signal is a control signal operating the process sequence.

15. The device according to claim 14 , further including
a voltage measuring device configured for detecting the temporal progression of a displacement voltage between an active conductor of the ungrounded power supply system and ground as a displacement voltage signal, which is correlated with the differential current signal in the computing unit.

Assignees

• Bender Gmbh & Co Kg
• Bender Gmbh Co Kg

Inventors

• Hackl Dieter
• Schepp Karl
• Becker Pascal

Classifications

• G01R31/083 Primary

  in cables, e.g. underground · CPC title

• G01R31/2839

  using signal generators, power supplies or circuit analysers (G01R31/2879 takes precedence; multimeters G01R15/12, network analysers G01R27/28) · CPC title

• G01R31/52

  Testing for short-circuits, leakage current or ground faults · CPC title

• G01R31/58

  Testing of lines, cables or conductors (testing of electric windings G01R31/72) · CPC title

• H02H3/165 Primary

  for three-phase systems · CPC title