Fiber Aligned and Motionally Coupled with Electric Cable

• US 20160139196A1
• Filed: 11/19/2015
• Published: 05/19/2016
• Est. Priority Date: 11/19/2014
• Status: Active Grant

• Current Assignee: Aiq Dienstleistungen Ug
• Original Assignee: Aiq Dienstleistungen Ug
• Inventors: Hoff, Henrik, Clement, Alf
• Granted Patent: US 10,215,793 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01R 31/1209 using acoustic measurements acoustic measurements G01H3/00
• CPC Class Codes: G01R 31/1218 using optical methods; using charged particle, e.g. electron, beams or X-rays
• CPC Class Codes: G01R 31/58 Testing of lines, cables or conductors testing of electric windings G01R31/72

Abstract

An arrangement comprising an electric cable, at least one fiber at least a part of which being aligned along and motionally, in particular vibrationally, coupled with the electric cable, and a device for detecting effects in the electric cable via said at least one fiber.

Claims

1. A device for detecting partial discharge in an electric cable, the device comprising:

an electromagnetic radiation source configured for generating primary electromagnetic radiation to be coupled into at least one fiber at least a part of which being aligned along and motionally, in particular vibrationally, coupled with the electric cable;

an electromagnetic radiation detector configured for detecting secondary electromagnetic radiation generated in the at least one fiber in response to the coupling of the primary electromagnetic radiation into the at least one fiber and being influenced by partial discharge induced local motion, in particular vibrations, of the electric cable, which local motions, in particular vibrations, couple to the at least one fiber;

a partial discharge determining unit configured for determining information indicative of the partial discharge in the electric cable based on an analysis of the motionally, in particular vibrationally, influenced secondary electromagnetic radiation detected by the electromagnetic radiation detector.

2. The device according to claim 1, wherein the device is configured for detecting the partial discharge in the electric cable by Distributed Acoustic Sensing.

3. The device according to claim 1, wherein the device is configured for detecting the partial discharge in the electric cable by Distributed Vibration Sensing.

4. The device according to claim 1, comprising a temperature information determining unit configured for determining temperature information along an extension of the electric cable by Distributed Temperature Sensing based on an analysis of secondary electromagnetic radiation detected in response to primary electromagnetic radiation to be coupled into a fiber at least a part of which being aligned along the electric cable.

5. The device according to claim 2, further comprising an alarm unit for providing an alarm based on the information indicative of the partial discharge.

6. The device according to claim 4, wherein the fiber used for determining information indicative of the partial discharge and the fiber used for determining the temperature information are at least partially the same fiber.

7. The device according to claim 1, wherein the partial discharge determining unit is configured for determining the information indicative of the partial discharge exclusively considering the influence of the partial discharge induced local motions, in particular regardless of electromagnetic radiation generated in the electric cable by the partial discharge.

8. The device according to claim 1, wherein the partial discharge determining unit is configured for determining positional information indicative of a position along the electric cable at which the partial discharge has occurred.

9. The device according to claim 1, wherein the partial discharge determining unit is configured for determining the information indicative of the partial discharge based on a pattern analysis of one or more features of the secondary electromagnetic radiation.

10. The device according to claim 1, wherein the partial discharge determining unit is configured for determining information indicative of a time distance (d) between subsequent partial discharge events at a certain position of the electric cable and the fiber.

11. The device according to claims 1, wherein the partial discharge determining unit is configured for determining information indicative of a time duration (w) of a partial discharge event at a certain position of the electric cable and the fiber,

wherein the device comprises in particular a decision unit configured for making a decision depending on at least one of the group consisting of the determined time distance (d) and the determined time duration (w).

12. The device according to claim 1, wherein the partial discharge determining unit is configured for determining spatially resolved information indicative of the partial discharge at a certain cable position of the electric cable based on an identification of a certain fiber position of the fiber to which a detected portion of the secondary electromagnetic radiation belongs and based on predetermined mapping information mapping cable positions to fiber positions.

13. An arrangement, comprising:

an electric cable;

at least one fiber at least a part of which being aligned along and motionally, in particular vibrationally, coupled with the electric cable;

a device according to claim 1 for detecting partial discharge in the electric cable.

14. The arrangement according to claim 13, wherein the fiber is provided separately from the electric cable.

15. The arrangement according to claim 13, wherein both the fiber and the electric cable are embedded within a common sheathing, or wherein the fiber is embedded directly within a conductor of the electric cable.

16. The arrangement according to claim 13, wherein at least the part of the fiber is acoustically coupled with the electric cable.

17. The arrangement according to claim 13, comprising a shielding provision, in particular a cladding of at least one of the electric cable and the fiber being opaque for the electromagnetic radiation, for shielding the fiber so as to disable electromagnetic radiation generated in the electric cable by partial discharge from propagating into the fiber.

18. The arrangement according to claim 13, wherein the fiber is a single mode fiber

19. The arrangement according to claim 13, wherein the electric cable is a multi-phase cable having multiple sub cables each assigned to a respective phase, and multiple fibers are provided,

wherein at least a part of each of the multiple fibers is aligned along a respective one of the sub cables,

wherein the electric cable is in particular a multi-phase cable having multiple sub cables each assigned to a respective phase, and in particular a single fiber is provided, wherein each of multiple sections of the single fiber is aligned along a respective one of the sub cables.

20. A method of detecting partial discharge in an electric cable, the method comprising:

coupling primary electromagnetic radiation into at least one fiber at least a part of which being aligned along and motionally, in particular vibrationally, coupled with the electric cable;

detecting secondary electromagnetic radiation generated in the at least one fiber in response to the coupling of the primary electromagnetic radiation into the at least one fiber and being influenced by partial discharge induced local motions, in particular vibrations, of the electric cable, which local motions, in particular vibrations, couple to the at least one fiber;

determining information indicative of the partial discharge in the electric cable based on an analysis of the motionally, in particular vibrationally, influenced detected secondary electromagnetic radiation.