Tone location device for locating faults in a paired line

• US 5,995,588 A
• Filed: 06/02/1997
• Issued: 11/30/1999
• Est. Priority Date: 09/01/1995
• Status: Expired due to Term

• Current Assignee: Greenlee Textron Incorporated (Emerson Electric Company)
• Original Assignee: Robert G. Crick
• Inventors: Crick, Robert G.
• Primary Examiner(s): Kuntz, Curtis A.
• Assistant Examiner(s): NGUYEN, DUC MINH
• Application Number:
  US08/867,310
• Time in Patent Office: 911 Days
• Field of Search: 379/1, 379/6, 379/21, 379/22, 379/25, 379/26, 379/27, 379/29-30, 379/32, 324/500, 324/512, 324/527-528, 324/529-530, 324/67, 324/541-542, 324/539-544, 455/41, 455/67.4
• US Class Current: 379/22
• CPC Class Codes: G01R 31/08 Locating faults in cables, transmission lines, or networks
• CPC Class Codes: G01R 31/085 in power transmission or distribution lines, e.g. overhead

Abstract

A device and method are provided for locating faults in a paired line. The fault locating device has a transmitting unit connectable to the conductors of a paired line containing the fault. The device also has a portable receiving unit to track the path of the paired line. The transmitting unit contains circuits for creating and transmitting a locator signal and a carrier signal including synchronization through the conductors toward the receiving unit. The receiving unit contains a pickup coil positioned proximal to the paired line, inducing induced locator and carrier signals in the pickup coil. The receiving unit also contains circuits for processing the induced locator and carrier signals and for producing a synchronization signal used to detect and segregate a component of the induced locator signal which is indicative of a fault. The presence or absence of the indicative component is communicated to an operator by means of an audible or visual fault indicator.

Claims

1. A device for locating a fault in a paired line comprising:

means connectable to a first point on a paired line for generating and introducing a locator signal into said paired line;

means connectable to said first point for generating and introducing a carrier signal into said paired line, wherein said carrier signal includes synchronization of said locator signal generating means;

means positionable at a second point on said paired line for creating an induced locator signal in response to said locator signal;

means positionable at said second point on said paired line for creating an induced carrier signal including said synchronization in response to said carrier signal;

means responsive to said induced locator signal and said induced carrier signal for detecting a component of said induced locator signal indicative of a fault; and

means for communicating an indicator of said component to an operator, wherein said communicated indicator enables location of said fault in said paired line.

2. The device of claim 1 wherein said locator signal generating means is a first locator signal generating means connectable to a first conductor at said first point for generating and introducing said first locator signal into said first conductor, said device further comprising a second means connectable to a second conductor at said first point on said paired line for generating and introducing a second locator signal into said second conductor.

3. The device of claim 1 wherein said induced locator signal creating means is a first induced locator signal creating means positionable at said second point on said paired line for creating said first induced locator signal in response to said locator signal, said device further comprising a second means positionable at said second point on said paired line for creating a second induced locator signal in response to said locator signal.

4. The device of claim 3 further comprising means for creating a balanced induced locator signal from said first and second induced locator signals.

5. The device of claim 1 wherein said component is a first component corresponding to a real phase of said locator signal generating means and said induced locator signal has a second component corresponding to a quadrature phase of said locator signal generating means, further wherein said detection means is a first detection means for detecting said first component, said device further comprising a second detection means for detecting said second component.

6. The device of claim 5 wherein said synchronization includes real synchronization and quadrature synchronization, said device further comprising means for generating and transmitting a real synchronization signal corresponding to said real synchronization to said first detection means and means for generating and transmitting a quadrature synchronization signal corresponding to said quadrature synchronization to said second detection means.

7. The device of claim 5 further comprising means for selecting said first component to the exclusion of said second component or selecting said second component to the exclusion of said first component aid transmitting said selected component to said indicator communicating means.

8. A device for locating a fault in a paired line comprising:

a locator signal output connectable to a first point on a paired line to generate a locator signal for transmission through said paired line to a second point on said paired line;

a carrier signal output connectable to said first point on said paired line to generate a carrier signal including synchronization for transmission through said paired line to a second point on said paired line;

a pickup coil movably positionable at said second point on said paired line to create an induced locator signal having at least one component indicative of a fault and to create an induced carrier signal including said synchronization;

a detector in electrical communication with said pickup coil to detect said at least one component; and

a synchronization signal output in electrical communication with said detector to create a synchronization signal corresponding to said synchronization included in said induced carrier signal.

9. The device of claim 8 wherein said detector is a first detector to detect a first component of said locator signal indicative of said fault to the exclusion of a second component of said locator signal indicative of said fault, said device further comprising a second detector to detect said second component to the exclusion of said first component.

10. The device of claim 9 further comprising a switch in selective electrical communication with said first detector or said second detector, and an audio speaker or a display responsive to said first component or said second component.

11. The device of claim 8 wherein said induced locator signal is a first induced locator signal, and further wherein said pickup coil has a first coil segment to create said first induced locator signal and a second coil segment to create a second induced locator signal in response to said locator signal generated by said locator signal output.

12. The device of claim 8 wherein said locator signal is a first locator signal, said device further comprising a locator signal transformer having a first outlet winding to deliver said first locator signal to said paired line and a second outlet winding to deliver a second locator signal of opposite polarity to said paired line.

13. The device of claim 11 further comprising an induced locator signal balancing circuit to produce a balanced induced locator signal in response to said first and second induced locator signals.

14. The device of claim 13 wherein said locator signal balancing circuit includes a balancing amplifier and a balancing potentiometer positioned in parallel.

15. The device of claim 9, further comprising a real synchronous oscillator in electrical communication with said first detector to transmit a real synchronization signal to said first detector and a quadrature synchronous oscillator in parallel with said real synchronous oscillator and in electrical communication with said second detector to transmit a quadrature synchronization signal to said second detector.

16. The device of claim 8 wherein said locator signal output is a locator signal oscillator.

17. The device of claim 8 wherein said carrier signal output is a carrier signal oscillator.

18. The device of claim 8 wherein said synchronization signal output is a demodulator.

19. A method for locating a fault in a paired line comprising:

a) generating a locator signal and a carrier signal including synchronization at a first point of a paired line, wherein said paired line has a fault;

b) electrically introducing said locator signal and said carrier signal into said paired line at said first point;

c) creating an induced locator signal and an induced carrier signal including synchronization at a second point on said paired line in response to said locator signal and said carrier signal;

d) detecting a component of said locator signal indicative of said fault; and

e) communicating an indicator of said component to an operator, wherein said communicated indicator enables location of said fault in said paired line.

20. The method of claim 19 wherein said locator signal is a first locator signal introduced into a first conductor at said first point and said method further comprises generating and electrically introducing a second locator signal into a second conductor at said first point on said paired line.

21. The method of claim 19 wherein said induced locator signal is a first induced locator signal created in response to said locator signal and said method further comprises creating a second induced locator signal in response to second locator signal.

22. The method of claim 21 further comprising balancing said first and second induced locator signals to produce a balanced induced locator signal.

23. The method of claim 19 wherein said component is a first component corresponding to a real phase of said locator signal and said locator signal has a second component indicative of said fault corresponding to a quadrature phase of said locator signal, said method further comprising detecting said second component.

24. The method of claim 23 further comprising segregating said first component from said second component.

25. The method of claim 19 wherein said synchronization includes real synchronization and quadrature synchronization, said method further comprising creating a real synchronization signal from said real synchronization to detect said first component and creating a quadrature synchronization signal from said quadrature synchronization to detect said second component.

26. The method of claim 23 further comprising selecting said first component to the exclusion of said second component or selecting said second component to the exclusion of said first component, wherein said indicator corresponds to said selected component.