System and Method to Locate an Anomaly of a Conductor

• US 20050194978A1
• Filed: 03/07/2005
• Published: 09/08/2005
• Est. Priority Date: 03/08/2004
• Status: Active Grant

• Current Assignee: LiveWire Innovation Inc.
• Original Assignee: LiveWire Test Labs, Inc.
• Inventors: Smith, Paul Samuel
• Granted Patent: US 7,075,309 B2
• Time in Patent Office: Days
• US Class Current: 324/527
• CPC Class Codes: G01R 31/083 in cables, e.g. underground
• CPC Class Codes: G01R 31/11 using pulse reflection methods

Abstract

A system (20) and method to locate an anomaly (22) of a conductor (24) is provided. The system (20) uses a test set (28) to inject a test signal (36) into the conductor (24) at a location (P_T) and a probe (30) to detect the test signal (36) at a second location (P_P). A communication link (42) between the probe (30) and the test set (28) has a predetermined propagation delay (D_S), from which the system (20) can calculate a propagation delay (D_TP) of the conductor (24) between the test set (28) and the probe (30), and a propagation delay (D_PA) between the probe (30) and the anomaly (22). By varying the location (P_P) of the probe (30) until the propagation delay (D_PA) between the probe (30) and the anomaly (22) is substantially zero, the precise location (P_A) of the anomaly (22) may be determined. The propagation velocity (V_C) of the conductor (24) may also be determined. The physical distance (L_PA) between the probe (30) and the anomaly (22), and hence the precise location (P_A) of the anomaly (22), again may be determined.

Claims

1. A system (20) to locate an anomaly (22) of a conductor (24), said system (20) comprising:

a test set (28) coupled to said conductor (24) at a location PT along said conductor (24) and configured to inject a test signal (36) into said conductor (24) at said location PT;

a probe (30) coupled to said conductor (24) at a location PP along said conductor (24) and configured to detect said test signal (36) at said location PP;

a communication link (42) configured to couple said probe (30) to said test set (28), said communication link having a propagation delay DS; and

a calculation unit (32) coupled to one of said probe (30) and said test set (28) and configured to calculate a propagation delay DTP of said conductor (24) between said location PT and said location PP in response to said propagation delay DS.

2. A system (20) as claimed in claim 1 wherein said probe (30) is electrically coupled to said conductor (24) at said location PP without physical contact.

3. A system (20) as claimed in claim 1 wherein said propagation delay DS comprises:

a propagation delay DTX within said test set (28);

a propagation delay DPX within said probe (30); and

a propagation delay DSX of a medium (48) coupling said probe (30) to said test set (28).

4. A system (20) as claimed in claim 3 wherein said medium (48) is one of:

said conductor (24);

a reference cable (44); and

an over-the-air radio-frequency link (46).

5. A system (20) as claimed in claim 3 wherein said calculation unit (32) is configured to calculate said propagation delay DS in response to said propagation delay DTX, said propagation delay DPX, and said propagation delay DSX.

6. A system (20) as claimed in claim 1 additionally comprising an output unit (34) coupled to said calculation unit (32) and configured to indicate said location PP relative to said location PT and a location PA of said anomaly (22).

7. A system (20) as claimed in claim 1 wherein said calculation unit (32) is configured to calculate a propagation delay DTA of said conductor (24) from said location PT to a location PA of said anomaly (22).

8. A system (20) as claimed in claim 7 wherein said calculation unit (32) is configured to calculate a propagation delay DPA in response to said propagation delay DTA and said propagation delay DTP.

9. A system (20) as claimed in claim 7 wherein said location PA is identified by adjusting said location PP until said calculation unit (32) calculates said propagation delay DPA to be substantially zero.

10. A system (20) as claimed in claim 1 wherein said calculation unit (32) is configured to calculate said propagation delay DS when a difference between said location PT and said location PP is substantially zero.

11. A system (20) as claimed in claim 1 wherein:

said test signal (36) is a reflectometric test signal; and

said test signal (36) is one of;

a pulse;

a digital sequence;

a spread-spectrum signal; and

a sequence of one or more sine waves.

12. A system (20) as claimed in claim 1 wherein:

said probe (3) is one of a plurality of said probes (30);

said location PP is one of a plurality of said locations PP;

said propagation delay DTP is one of a plurality of said propagation delays DTP;

each of said probes (30) is coupled to said conductor (24) at a unique one of said locations PP; and

said calculation unit (32) is configured to calculate a unique one of said propagation delays DTP of said conductor between said location PT and each of said locations PP in response to said propagation delay DS.

13. A method to locate an anomaly (22) of a conductor (24), said method comprising:

establishing a communication link (42) between a probe (30) and a test set (28);

determining a propagation delay DS of said communication link (42);

injecting a test signal (36) at a location PT along said conductor (24) using said test set (28);

detecting said test signal (36) at a location PP along said conductor (24) using said probe (30); and

calculating a propagation delay DTP between said location PT and said location PP in response to said propagation delay DS.

14. A method as claimed in claim 13 additionally comprising electrically coupling said probe (30) to said conductor (24) without physical contact.

15. A method as claimed in claim 13 additionally comprising:

ascertaining a physical distance LTP along said conductor (24) between said location PT and said location PP; and

calculating a propagation velocity VC of said conductor (24) in response to said physical distance LTP and said propagation delay DTP.

16. A method as claimed in claim 13 additionally comprising:

ascertaining a propagation velocity VC of said conductor (24); and

calculating, in response to said propagation velocity VC, one of;

a physical distance LTP along said conductor (24) between said location PT and said location PP;

a physical distance LTA along said conductor (24) between said location PT and said location PA; and

a physical distance LPA along said conductor (24) between said location PP and a location PA of said anomaly (22).

17. A method as claimed in claim 13 additionally comprising:

calculating a propagation delay DTA of said conductor (24) from said location PT to a location PA of said anomaly (22); and

calculating a propagation delay DPA of said conductor (24) from said location PT to said location PA in response to said propagation delay DTA and said propagation delay DTP.

18. A method as claimed in claim 17 additionally comprising identifying said location PA by adjusting said location PP until said propagation delay DPA is substantially zero.

19. A method as claimed in claim 13 wherein said detecting activity comprises adjusting an attitude of said probe (30) proximate said conductor (24) until said detected test signal (36) achieves a maximum amplitude.

20. A system (20) to locate an anomaly (22) of a conductor (24), said system (20) comprising:

a test set (28) coupled to said conductor (24) at a location PT along said conductor (24) and configured to inject a test signal (36) into said conductor (24) at said location PT, wherein said test signal (36) is one of;

a time-domain reflectometry pulse;

a digital sequence;

a spread-spectrum signal; and

a sequence of one or more sine waves;

a probe (30) coupled to said conductor (24) at a location PP and configured to detect said test signal (36) at said location PP; and

a calculation unit (32) coupled to one of said test set (28) and said probe (30) and configured to calculate a propagation delay D_PA of said conductor (24) from said location PP to a location PA of said anomaly (22).

21. A system (20) as claimed in claim 20 wherein said location PA is identified by adjusting said location PP until said calculation unit (32) calculates said propagation delay DPA to be substantially zero.

22. A system (20) as claimed in claim 20 wherein one of said test set (28) and said probe (30) is electrically coupled to said conductor (24) by one of:

inductive coupling;

capacitive coupling; and

radiative coupling.

23. A system (20) as claimed in claim 20 wherein said probe (30) is adjusted at said location PP to an attitude where said detected test signal (36) achieves a maximum amplitude.

24. A system (20) as claimed in claim 20 additionally comprising an indication unit (34) coupled to said calculation unit (32) and configured to indicate one of:

an amplitude of said test signal (36) detected by said probe (30);

said location PP relative to said location PT; and

said location PP of said probe (30) relative to said location PA.