Identifying one of a plurality of wires of a power transmission cable

• US 20020027496A1
• Filed: 09/07/2001
• Published: 03/07/2002
• Est. Priority Date: 12/30/1999
• Status: Active Grant

• Current Assignee: Ambient S A
• Original Assignee: Ambient S A
• Inventors: Cern, Yehuda, Kaplun, George
• Granted Patent: US 6,646,447 B2
• Time in Patent Office: Days
• US Class Current: 340/310.01
• CPC Class Codes: H04B 2203/5487 cables
• CPC Class Codes: H04B 3/56 Circuits for coupling, blocking, or by-passing of signals

Abstract

There is provided an apparatus for enabling communication of a data signal via a power transmission cable. The apparatus comprises (a) a first winding for coupling the data signal via a conductor of the power transmission cable, and (b) a second winding, inductively coupled to the first winding, for coupling the data signal via a data port.

Claims

1. An apparatus for enabling communication of a data signal via a power transmission cable, comprising:

a first winding for coupling said data signal via a conductor of said power transmission cable; and

a second winding, inductively coupled to said first winding, for coupling said data signal via a data port.

2. The apparatus of claim 1, wherein said conductor is a first neutral conductor of said power transmission cable.

3. The apparatus of claim 2, wherein said first winding is connected in series between said first neutral conductor and a ground.

4. The apparatus of claim 2, wherein said first winding is connected in series between said first neutral conductor and a second neutral conductor of said power transmission cable.

5. The apparatus of claim 4, wherein said data signal is driven differentially through said first neutral conductor and said second neutral conductor.

6. The apparatus of claim 5, further comprising a core having:

a first region adjacent to said first neutral conductor; and

a second region adjacent to said second neutral conductor,

wherein said second winding is wound around a portion of said core, and

wherein said second winding induces a first current in said first neutral conductor in a first direction, and induces a second current in said second neutral conductor in a second direction that is opposite of said first direction.

7. The apparatus of claim 6, wherein said core is topographically configured as a figure “

8”

with no contact at the crossing point of the “

8”

.

8. The apparatus of claim 7,

wherein said first region comprises a first loop of said figure “

8”

,

wherein said first conductor is routed through said first loop,

wherein said second region comprises a second loop of said figure “

8”

, and

wherein said second conductor is routed through said second loop.

9. The apparatus of claim 7,

wherein said first region comprises a first gap in a first loop of said figure “

8”

,

wherein said first conductor is routed through said first gap,

wherein said second region comprises a second gap in a second loop of said figure “

8”

, and

wherein said second conductor is routed through said second gap.

10. The apparatus of claim 4, wherein said first neutral conductor and said second neutral conductor are substantially parallel to one another in said power transmission cable.

11. The apparatus of claim 4, further comprising a core, wherein said first winding comprises:

a grounded center tap;

a first portion connected to said first neutral conductor, wound in a first direction around said core, and connected to said grounded center tap; and

a second portion connected to said second neutral conductor, wound in a second direction around said core, and connected to said grounded center tap.

12. The apparatus of claim 4,

wherein said power transmission cable has a plurality of neutral wires that are substantially parallel to one another, with individuals of a first subset of said plurality of neutral conductors alternating with individuals of a second subset of said plurality of neutral conductors,

wherein said first neutral conductor comprises said first subset of said plurality of neutral conductors, and

wherein said second neutral conductor comprises said second subset of said plurality of neutral conductors.

13. The apparatus of claim 4, further comprising

a magnetic toroid core disposed around a portion of said power transmission cable,

wherein said first neutral conductor and said second neutral conductor are connected to a common terminating member downstream of said magnetic toroid core, and

wherein said first winding is connected to said first and second neutral conductors upstream of said magnetic toroid core.

14. The apparatus of claim 13, wherein said first and second windings are disposed within a balun transformer.

15. The apparatus of claim 2, further comprising an open magnetic core having:

a first leg positioned proximate and perpendicular to said first neutral conductor;

a second leg positioned proximate and perpendicular to a second neutral conductor of said power transmission cable; and

a third leg, located between said first leg and said second leg, having said first winding wound thereabout.

16. The apparatus of claim 2, further comprising:

a first magnetic toroidal core having a gap through which said first neutral conductor is routed;

a second magnetic toroidal core having a gap through which a second neutral conductor of said power transmission cable is routed,

wherein said first winding is wound around a portion of said first magnetic toroidal core and a portion of said second magnetic toroidal core.

17. The apparatus of claim 2, further comprising:

a third winding for coupling said data signal via a second neutral conductor of said power transmission cable; and

a fourth winding, inductively coupled to said third winding, for coupling said data signal via said data port,

wherein said data signal travels in a first path via said first neutral conductor, said first winding and said second winding, and in a second path via said second neutral conductor, said third winding and said fourth winding, and

wherein said first path is in parallel with said second path.

18. The apparatus of claim 2, wherein said data signal is a first data signal, and wherein said apparatus further comprises:

a third winding for coupling a second data signal via a second neutral conductor of said power transmission cable; and

a fourth winding, inductively coupled to said third winding, for coupling said second data signal to a second data port.

19. The apparatus of claim 1, wherein said conductor is a phase conductor of said power transmission cable.

20. The apparatus of claim 19, wherein said phase conductor is part of a medium voltage grid of the power distribution system.

21. The apparatus of claim 19, further comprising a core through which said phase conductor is routed, wherein said second winding is wound around a portion of said core.

22. The apparatus of claim 21, wherein said core has an air gap.

23. The apparatus of claim 19, further comprising a capacitor in series between said second winding and a ground.

24. The apparatus of claim 19, further comprising a surge protector connected in parallel with said second winding.

25. The apparatus of claim 1, further comprising:

a first modem having a first port coupled to said data port of said second winding, and having a second port for further coupling of said data signal; and

a second modem having a first port coupled to said second port of said first modem, and having a second port for further coupling of said data signal.

26. The apparatus of claim 25, wherein said first modem and said second modem are configured back-to back.

27. The apparatus of claim 25, further comprising a data router interposed between said first modem and said second modem.

29. The data communication network of claim 28,

wherein said inductive coupler is located proximate to a distribution transformer of said power distribution system,

wherein said distribution transformer has a power line output, and

wherein said data communication network further comprises a capacitor for coupling said data signal between said data port and said power line output.

30. The data communication network of claim 28, wherein said phase conductor is part of a medium voltage grid of said power distribution system.

31. The data communication network of claim 28, wherein said end of said power transmission cable is at a medium voltage output terminal of a high voltage to medium voltage transformer of said power distribution system.

32. The data communication network of claim 28, further comprising a node, located between said capacitive coupler and said ground, for coupling said data signal between said phase conductor and a second data port.

33. The data communication network of claim 28, wherein said inductive coupler comprises a current transformer having a winding coupled to said data port.

34. The data communication network of claim 33,

wherein said current transformer further comprises a core through which said phase conductor is routed, and

wherein said winding is wound around a portion of said core.

35. The data communication network of claim 34, wherein said core has an air gap.

36. The data communication network of claim 33, further comprising a capacitor in series with said winding and said data port.

37. The data communication network of claim 33, further comprising a surge protector connected in parallel with said winding.

38. The data communication network of claim 28, wherein said capacitive coupler comprises:

a capacitor;

a high frequency isolation transformer;

a fuse;

a bleeder resistor; and

a termination resistor having a resistance approximately equal to a characteristic impedance of said power transmission cable.

40. The data communication network of claim 39,

wherein said first segment comprises a first power distribution cable on a first side of a power distribution transformer, and

wherein said second segment comprises a second power distribution cable on a second side of said power distribution transformer.

41. The data communication network of claim 40,

wherein said power distribution transformer has an output power line, and

wherein said data communication network further comprises a capacitor between said data port of said first inductive coupler and said output power line, for coupling said data signal to said output power line.

42. The apparatus of claim 40, further comprising:

a first modem having a first port coupled to said data port of said first coupler, and having a second port for further coupling of said data signal; and

a second modem having a first port coupled to said second port of said first modem, and having a second port for further coupling of said data signal.

43. The apparatus of claim 42,

wherein said power distribution transformer has an output power line, and

wherein said data communication network further comprises a capacitor between said second port of said second modem and said output power line, for coupling said data signal to said output power line.

28. A data communication network implemented over a power distribution system having a power transmission cable with a phase conductor, comprising:

an inductive coupler for coupling a data signal via said phase conductor, and having a data port for further coupling of said data signal; and

a capacitive coupler, connected between said phase conductor and a ground, proximate to an end of said power transmission cable, for absorbing reflections of said data signal.

39. A data communication network implemented over a power distribution system having a first segment with a first neutral conductor, and having a second segment with a second neutral conductor, comprising:

a first coupler for inductively coupling a data signal via said first neutral conductor, and having a data port for further coupling of said data signal; and

a second coupler having a data port coupled to said data port of said first inductive coupler, and for inductively coupling said data signal via said second neutral conductor.

44. A data communication network implemented over a power distribution system having a power transmission cable with a phase conductor, comprising:

an inductive coupler having a first port for coupling a data signal via said phase conductor, and having a second port for further coupling of said data signal.

45. The data communication network of claim 44, wherein said inductive coupler is a radio frequency (RF) transformer.

46. The data communication network of claim 44, wherein said data communication network further comprises a capacitor connected in series with said first port and said phase conductor.

47. The data communication network of claim 46,

wherein said power distribution system includes a voltage step-down transformer,

wherein said inductive coupler is located proximate to a secondary winding of said voltage step-down transformer, and

wherein said data communication network further comprises a component having an impedance that when reflected through said inductive coupler is approximately equal to a characteristic impedance of said power transmission cable.

48. The data communication network of claim 47, wherein said component is a modem.

49. The data communication network of claim 44,

wherein said power distribution system includes a transition between an overhead cable and an underground cable,

wherein said underground cable has a characteristic impedance that is lower than that of said overhead cable, and

wherein said inductive coupler is located on said overhead cable, proximate to said transition.

50. The data communication network of claim 44,

wherein said inductive coupler induces a first current in said phase conductor in a first direction,

wherein said data communication network further comprises a second inductive coupler for coupling said data signal via a second phase conductor of said power transmission cable, and

wherein said second inductive coupler induces a second current in said second phase conductor in a direction opposite of said first current.

51. The data communication network of claim 44, wherein said inductive coupler is located on a line that feeds a primary winding of a distribution transformer of said power distribution system.

52. The data communication network of claim 44,

wherein said power distribution system includes a component between said phase conductor and a ground,

wherein said component has a characteristic impedance of less than that of said power transmission cable, and

wherein said data communication network further comprises a choke in series with said component.

53. The data communication network of claim 52, wherein said component is selected from the group consisting of a power factor correction capacitor, and a power line communications (PLC) capacitor.

54. The data communication network of claim 52, wherein said choke comprises a magnetic core disposed around a length of a wire that connects said component to said phase conductor.

55. The data communication network of claim 44,

wherein said inductive coupler induces a first current in said first phase conductor via a first winding,

wherein the data communication network further comprises a second inductive coupler for coupling said data signal via a second phase conductor of said power transmission cable,

wherein said second inductive coupler induces a second current in said second phase conductor via a second winding, and

wherein said first winding and said second winding are in parallel with one another.

58. The method of claim 57, wherein said identifying step identifies said selected neutral wire as said one of said plurality of neutral wires having a greatest relative magnitude.

59. The method of claim 57, wherein said applying step comprises inductively coupling said signal to said selected neutral wire.

60. The method of claim 57, wherein said sensing step comprises inductively coupling said signal from said selected neutral wire.

56. A data communication network implemented over a power distribution system having a phase conductor with a first segment on a first side of a switch and a second segment on a second side of said switch, comprising:

a first capacitive coupler for coupling a data signal via said first segment, and having a data port for further coupling of said data signal; and

a second capacitive coupler having a data port coupled to said data port of said first capacitive coupler, and for coupling said data signal via said second segment,

wherein a transmission of said data signal between said first segment and said second segment is maintained when said switch is opened.

57. A method for identifying one of a plurality of neutral wires of a power transmission cable, comprising:

applying a signal to a selected neutral wire, at a first point on said power transmission cable;

sensing a relative magnitude of said signal on each of said plurality of neutral wires at a second point on said power transmission cable that is remote from said first point; and

identifying said selected neutral wire from said relative magnitudes.

61. A system for identifying one of a plurality of neutral wires of a power transmission cable, comprising:

a receiver for sensing a signal from a selected neutral wire of said power transmission cable; and

an indicator of a magnitude of said signal,

wherein said signal is applied to said selected wire at a first point on said power transmission cable, and said receiver senses said signal at a second point on said power transmission cable that is remote from said first point.

62. The system of claim 61, further comprising:

a ferrite toroid having a radial slot through which said selected neutral wire is routed; and

a winding that is wound around a portion of said ferrite toroid and connected to an input of said receiver,

wherein said signal is inductively coupled from said selected neutral wire via said ferrite toroid.

63. The system of claim 61, further comprising an inductive coupler through which said signal is applied to said selected neutral wire at said first point.