Power transmission line monitoring system

• US 5,181,026 A
• Filed: 12/19/1990
• Issued: 01/19/1993
• Est. Priority Date: 01/12/1990
• Status: Expired due to Fees

• Current Assignee: Granville Group Incorporated
• Original Assignee: Granville Group Incorporated
• Inventors: Granville, J. Michael
• Primary Examiner(s): Yusko, Donald J.
• Assistant Examiner(s): Holloway, III, Edwin C.
• Application Number:
  US07/632,249
• Time in Patent Office: 762 Days
• Field of Search: 340/870.28, 340/870.17, 340/870.29, 340/310 R, 340/538, 340/658, 340/657, 340/660, 340/664, 324/126, 324/127, 324/142, 324/117 R, 324/96, 364/481, 364/483, 364/492, 323/357, 361/93, 361/91, 385/26, 359/173, 359/179
• US Class Current: 340/870.28
• CPC Class Codes: G01R 15/183 using transformers with a magnetic core
• CPC Class Codes: G01R 21/133 by using digital technique
• CPC Class Codes: H02H 1/0069 by means of light or heat rays
• CPC Class Codes: H02H 1/06 Arrangements for supplying operative power power supply arrangements in general G05F, H02M
• CPC Class Codes: H02J 13/00002 characterised by monitoring
• CPC Class Codes: H02J 13/00017 using optical fiber
• CPC Class Codes: H02J 13/00019 using optical means
• CPC Class Codes: H02J 13/00034 the elements or equipment being or involving an electric power substation
• CPC Class Codes: H02J 13/0004 involved in a protection system
• CPC Class Codes: Y02E 60/00 Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
• CPC Class Codes: Y04S 10/00 Systems supporting electrical power generation, transmission or distribution
• CPC Class Codes: Y04S 10/30 State monitoring, e.g. fault, temperature monitoring, insulator monitoring, corona discharge
• CPC Class Codes: Y04S 40/124 using wired telecommunication networks or data transmission busses

Abstract

An Electric Power Line Monitoring System in which a single line measuring system station can measure all of the power parameters of both voltage and phase angle plus ambient and line temperatures. The measuring station can be secured to the power line without the need for shutting down the line. The measured data is transmitted from the measuring station on the power line to a ground receiving and data processing station. The system measures true RMS voltage and current values, RMS phase angle along with ambient and line temperatures which are digitized and transmitted through a digital fiber optic data link. The fiber optic data transmission line can be a flexible fiber optic cable assembly or a rigid fiber optic bushing assembly for supporting a long phase conductor that also contains a long resistive link of a voltage sensor voltage divider. The resistive link is constructed of materials that have a high precision resistance tolerance and low temperature coefficients of resistance that improved the accuracy of the voltage sensor.

Claims

1. A power transmission line monitoring system comprising;

current sampling means for sampling current on a power transmission line;

rectifying means for rectifying the output of said current sampling means;

power supply means connected to the output of said rectifying means for producing regulated filtered electrical power;

line voltage sensing means connected to said power transmission line, said line voltage sensing means including a voltage divider comprised of a small resistance connected to said power transmission line in series with a very large resistance connected to earth ground;

signal processing means for receiving and processing the data output of said line voltage sensing means, signal processing means including data processing and data transmission means for transmitting said data output of said line voltage sensing means across the line to ground voltage gradient to a ground receiving and data processing station located remotely from said power transmission line, said data transmitting means comprising a fiber optic data transmission cable that includes said very large resistance of said voltage divider;

voltage divider current loss measuring circuit means for measuring current loss across said voltage divider by the continuous measurement and comparison of the current magnitude at the power line end of said line voltage sensing voltage divider with the current magnitude at the earth ground end of said line voltage sensing voltage divider, said comparison data processing performed at said ground receiving and data processing station, said voltage divider power line end current magnitude measured by said line voltage sensing means, and said voltage divider earth ground end current magnitude measured by a voltage divider earth ground end current sensing circuit means, said voltage divider earth ground end current sensing circuit means being part of said ground receiving and data processing station; and

a common system return connecting said current sampling means, said rectifying means, said power supply means, said line voltage sensing means, and said signal processing means to said power transmission line whereby system circuits are isolated from earth ground by using the power transmission line as a reference and as the common system circuitry return.

2. The power line monitoring system according to claim 1 wherein said line voltage sensing means data output is in analog real time waveform units received by said signal processing and data transmitting means for processing and transmitting, said transmission means transmitting said analog real time waveform units in real time analog form, from the output of an AC to RMS converter circuit means in analog form.

3. The power transmission line monitoring system according to claim 2 including stray capacitance compensating circuitry means for reducing the amount of current loss from said voltage divider.

4. The power transmission line monitoring system according to claim 3 wherein said stray capacitance compensating circuitry means comprises a second outer twin resistance voltage divider parallel to the first inner voltage divider, said second outer twin resistance voltage divider comprised of a small resistance connected to said power transmission line in series with a very large resistance connected to earth ground, said second outer twin resistance voltage divider being coupled to said first inner line voltage sensing voltage divider by shield means.

5. The power transmission line monitoring system according to claim 4 wherein said shield means electrically coupling said first inner line voltage sensing voltage divider to said second outer twin resistance voltage divider comprises a series of spaced shield rings connected to said second outer voltage divider with each individual shield ring forming a closed earth enclosing a small linear segment of the length of said first inner line voltage sensing voltage divider, with the spatial orientation of the geometric plane formed within said closed path roughly parallel to the plane of the earth ground surface below said first inner line voltage sensing voltage divider small linear segment.

6. The power transmission line monitoring system according to claim 5 including a line electrostatic field meter means for measuring the line electric field phasor connected to said common system return, said electric field. phasor data output from said line electrostatic field meter means is in real time analog waveform units to phase angle sensing circuit means with said phase angle sensing circuit means having an analog data output to said signal processor means, and also to said signal processor means directly for receiving, processing and transmitting of said electric field phasor real time analog waveform data output as a real time analog waveform, said data transmitting means of said signal processor means comprising a fiber optic data transmission cable.

7. The power line monitoring system according to claim 6 including an ambient temperature sensing means thermally coupled to the ambient air adjacent to the power transmission line for sensing the ambient air temperature, said ambient temperature sensing means circuitry connected to said common system return, with analog ambient temperature data being output to signal processing means for receiving, processing, and transmission of said data to a ground receiving and data processing station located remotely from said power transmission line, said data transmitting means comprising a fiber optic data transmission cable.

8. The power line monitoring system according to claim 7 including a radiant energy unit comprising an alternative electrical energy source for supplying electrical power to the line monitoring system circuitry, with electrical power from said line current sampling means.

9. The power line monitoring system according to claim 8 in which said radiant energy unit comprises;

an optical radiant energy means;

an optical radiant energy transmission medium means for containing, routing, and transmission of said radiant energy across the ground to line voltage gradient from said radiant energy source, said optical radiant energy transmission medium means contained within and a component of said fiber optic data transmission cable; and

a photovoltaic array mounted on said power transmission line optically coupled to said optical radiant energy transmission medium means to receive said incident optical radiant energy, and to convert said optical radiant energy into electrical energy, which is connected to and is referenced to said common system return.

10. The power line monitoring system according to claim 9 in which said optical radiant energy transmission medium means comprises an optical radiant energy conducting optical fiber bundle, said optical fiber bundle assembled from a plurality of discrete optical fibers, said optical fiber bundle optically coupling and connecting said photovoltaic array to said optical radiant energy source means contained within and a component of said fiber optic data transmission cable.

11. The power line monitoring system according to claim 10 in which said optical radiant energy source means is an incandescent lamp.

12. The power line monitoring system according to claim 11 including a battery for storing electrical power being said electrical power available to supply said line monitoring system circuitry during the time period of any transitions from power supplied by said current sampling means over to power supplied from said radiant energy unit, said battery connected to and referenced to said common system return.

13. A power transmission line monitoring system comprising;

current sampling means for sampling current on a transmission line;

rectifying means for rectifying the output of said current sampling means;

power supply means connected to the output of said rectifying means for producing regulated filtered electrical power;

line current sensing means connected to said rectifying means for sensing line current;

signal processing means for receiving and processing the data output of said line current sensing means, signal processing means including data processing and data transmission means for transmitting said data output of said line current sensing means to a ground receiving and data processing station located remotely from said power transmission line, said data transmission means comprising a fiber optic data transmission cable; and

a common system return connecting said current sampling means, said rectifying means, said power supply means, said line current sensing means, and said signal processing means to said power transmission line whereby system circuits are isolated from earth ground by using the power transmission line as a reference and as the common system circuitry return.

14. The power transmission line monitoring system according to claim 13, wherein said line current sensing means data output in analog real time waveform units received by said signal processing and data transmitting means for analog processing and transmitting, said transmission means transmitting said real time waveform units in real time analog form, Ac to true RMS converter circuit means in analog form.

15. The power transmission line monitoring system according to claim 14 including a line electrostatic field meter means for measuring the line electric field phasor connected to said common system return, said electric field phasor data output from said line electrostatic field meter means is in real time analog waveform units to phase angle sensing circuit means with said phase angle sensing circuit means having an analog data output to said signal processor means, and also to said signal processor means directly for receiving, processing and transmitting of said electric field phasor real time analog waveform data output as a real time analog waveform, said data transmitting means of said signal processor means comprising a fiber optic data transmission cable.

16. The power line monitoring system according to claim 15 including a radiant energy unit comprising an alternative electrical energy source for supplying electrical power to the line monitoring system circuitry, with electrical power from said line current sampling means.

17. The power line monitoring system according to claim 16 in which said radiant energy unit comprises:

an optical radiant energy means;

an optical radiant energy transmission medium means for containing, routing, and transmission of said radiant energy across the ground to line voltage gradient from said radiant energy source, said optical radiant energy transmission medium means contained within and a component of said fiber optic data transmission cable;

a photovoltaic array mounted on said power transmission line optically coupled to said optical radiant energy transmission medium means to receive said incident optical radiant energy, and to convert said optical radiant energy into electrical energy, which is connected to and is referenced to said common system return.

18. The power line monitoring system according to claim 17 in which said optical radiant energy transmission medium means comprises an optical radiant energy conducting optical fiber bundle, said optical fiber bundle assembled from a plurality of discrete optical fibers, said optical fiber bundle optically coupling and connecting said photovoltaic array to said optical radiant energy source means contained within and a component of said fiber optic data transmission cable.

19. The power line monitoring system according to claim 18 in which said optical radiant energy source means is an incandescent lamp.

20. The power line monitoring system according to claim 19 including a battery for storing electrical power being said electrical power available to supply said line monitoring system circuitry during the time period of any transitions from power supplied by said current sampling means over to power supplied from said radiant energy unit, said battery connected to and referenced to said common system return.

21. A power transmission line monitoring system comprising;

current sampling means for sampling current on a transmission line;

rectifying means for rectifying the output of said current sampling means;

power supply means connected to the output of said rectifying means for producing regulated filtered electrical power;

line temperature sensing means connected to said power transmission line for sensing power transmission line phase conductor temperature;

signal processing means for receiving and processing the data output of said line temperature sensing means, signal processing means including data processing and data transmission means for transmitting said data output of said line temperature sensing means to a ground receiving and data processing station located remotely from said power transmission line, said data transmission means comprising a fiber optic data transmission cable; and

a common system return connecting said current sampling means, said rectifying means, said power supply means, said line temperature sensing means, and said signal processing means to said power transmission line whereby system circuits are isolated from earth ground by using the power transmission line as a reference and as the common system circuitry return.

22. The power line monitoring system according to claim 21 including a line current sensing means is connected to said rectifying means for sensing line current, and connected to and referenced to said common system return, with real time analog current waveform data output to signal processing means for receiving and processing the data output of said line current sensing means, signal processing means including data processing and data transmission means for transmitting said data output of said line current sensing means to a ground receiving and data processing station located remotely from said power transmission line, said data transmitting means comprising a fiber optic data transmission cable, and said transmitting means transmitting said current data output in real time waveform units, from the output of AC to true RMS converter circuit.

23. The power line monitoring system according to claim 22 including an ambient temperature sensing means thermally coupled to the ambient air adjacent to the power transmission line for sensing the ambient air temperature, said ambient temperature sensing means circuitry connected to and referenced to said common system return, with analog ambient temperature data being output to signal processing means for receiving, processing, and transmission of said data output to a ground receiving and data processing station located remotely from said power transmission line, said transmitting means comprising a fiber optic data transmission cable.

24. A power transmission line monitoring system comprising;

current sampling means for sampling current on a power transmission line;

rectifying means for rectifying the output of said current sampling means;

power supply means connected to the output of said rectifying means for producing regulated filtered electrical power;

line current sensing means connected to said rectifying means for sensing line current;

line voltage sensing means connected to said power transmission line, said line voltage sensing means including a voltage divider comprised of a small resistance connected to said power transmission line in series with a very large resistance connected to earth ground;

line electrostatic field meter means for measuring the line electric field phasor;

signal processing means for receiving the data output of and for processing the data output of said line current sensing means, said line voltage sensing means, and said line electrostatic field meter means, said signal processing means including data processing and data transmitting means for transmitting said data output across the line to ground voltage gradient to a ground receiving and data processing station located remotely from said power transmission line, said data transmitting means comprising a fiber optic data transmission cable that includes said very large resistance of said voltage divider;

voltage divider current loss measuring circuit means for measuring current loss across said voltage divider by the continuous measurement and comparison of the current magnitude at the power line end of said line voltage sensing voltage divider with the current magnitude at the earth ground end of said line voltage sensing voltage divider, said comparison data processing performed at said ground receiving and data processing station, said voltage divider power line end current magnitude measured by said line voltage sensing means, and said voltage divider earth ground end current magnitude measured by a voltage divider earth ground end current sensing circuit means, said voltage divider earth ground end current sensing circuit means part of said ground receiving and data processing station; and

a common system return connecting said current sampling means, said rectifying means, said power supply means, said line current sensing means, said line voltage sensing means, said line electrostatic field meter means, and said signal processing means to said power transmission line whereby system circuits are isolated from earth ground by using the power transmission line as a reference and as the common system circuitry return.

25. The power line monitoring system according to claim 24 wherein said line circuit sensing means, and said line electrostatic field meter means data output in real time waveform units is received by said signal processing and data transmitting means for processing and transmitting, said data transmitting means transmitting said real time waveform units from the output of an AC to turn RMC converter circuit means and in RMS phase angle units from the output of a line phase angle sensing circuit means, said line phase angle sensing circuit means receiving a real time waveform data input of line current from said line current sensing means of the line electric field phasor from said line electrostatic field meter means, and of the line voltage from said line voltage sensing means.

26. The power transmission line monitoring system according to claim 25 including stray capacitance compensating circuitry means for reducing the amount of current loss from said line voltage sensing voltage divider.

27. The power transmission line monitoring system according to claim 26 wherein said stray capacitance compensating circuitry means comprises a second outer twin resistance voltage divider parallel to the first inner voltage divider, said second outer twin resistance voltage divider comprised of a small resistance connected to said power transmission line in series with a very large resistance connected to earth ground, said second outer twin resistance voltage divider being coupled to said first inner line voltage sensing voltage divider by shield means.

28. The power transmission line monitoring system according to claim 27 wherein said shield means electrically coupling said first inner line voltage sensing voltage divider to said second outer twin resistance voltage divider comprises a series of spaced shield rings connected to second outer voltage divider with each individual said shield ring forming a closed path enclosing a small linear segment of the length of said first inner line voltage sensing voltage divider, with the spatial orientation of the geometric plane formed within said closed path roughly parallel to the plane of the earth ground surface below said first inner line voltage sensing voltage divider small linear segment.

29. The power transmission line monitoring system according to claim 28 including ambient temperature sensing means thermally coupled to the ambient air adjacent to the power transmission line for sensing the ambient air temperature, said ambient temperature sensing means circuitry connected to said common system return, with analog ambient temperature data output to signal processing means for receiving, processing, and transmission of said data to a ground receiving and data processing station located remotely from said power transmission line, said transmitting means comprising a fiber optic data transmission cable.

30. The power transmission line monitoring system according to claim 29 including a line temperature sensing means connected to said power transmission line for sensing power transmission line phase conductor temperature, with analog data output from said line temperature sensing means to temperature sensing circuit means, said circuit means having an analog data output to said signal processing means, said signal processing means including analog or digital data processing and analog or digital data transmission means for transmitting said data output of said line temperature sensing means to a ground receiving and data processing station located remotely from said power transmission line, said data transmitting means comprising a fiber optic data transmission cable, and said line temperature sensing means and temperature sensing circuit means connected to and referenced to said common system return.

31. The power transmission line monitoring system according to claim 30 including a radiant energy unit comprising an alternative electrical energy source for supplying electrical power to the line monitoring system circuitry, with electrical power from said line current sampling means.

32. The power transmission line monitoring system according to claim 31 in which said radiant energy unit comprises:

an optical radiant energy means;

an optical radiant energy transmission medium means for the containing, routing, and transmission of said radiant energy across the ground to line voltage gradient from said radiant energy source, said optical radiant energy transmission medium means contained within and a component of said fiber optic data transmission cable;

a photovoltaic array mounted on said power transmission line optically coupled to said optical radiant energy transmission medium means to receive said incident optical radiant energy, and to convert said optical radiant energy into electrical energy, which is connected to and is referenced to said common system return.

33. The power transmission line monitoring system according to claim 32 in which said optical radiant energy transmission medium means comprises an optical radiant energy conducting optical fiber bundle, said optical fiber bundle assembled from a plurality of discrete optical fibers, said optical fiber bundle optically coupling and connecting said photovoltaic array to said optical radiant energy source means contained within and a component of said fiber optic data transmission cable.

34. The power transmission line monitoring system according to claim 33 which said optical radiant energy source means is an incandescent lamp.

35. The power transmission line monitoring system according to claim 34 including a battery for storing electrical power, said electrical power being available to supply said line monitoring system circuitry during the time period of any transitions from power supplied by said current sampling means over to power supplied from said radiant energy unit, said battery connected to and referenced to said common system return.

36. A flexible high voltage gradient bridging dielectric optical data transmission fiber optic assembly for transmitting optical data across, and for enabling a very large resistance of a voltage sensing voltage divider to be routed across, a high voltage gradient which comprises within the cable assembly;

a voltage sensing voltage divider vary large resistance elongated resistive link;

data transmission optical fibers;

a mastic matrix for encapsulating optical fibers;

a polymeric dielectric strength member;

a polymeric insulating jacket; and

a series of polymeric insulating sheds along the length of the outer surface of said cable.

37. The cable assembly according to claim 36 in which said mastic matrix, strength member, insulating sheds, and insulating jacket components are provided by fewer than four components.

38. The cable assembly according to claim 36 in which said elongated resistive link is comprised of a continuous resistive link filament means.

39. The cable assembly according to claim 38 in which said continuous resistive link filament means is an electrically conductive plastic selected from the group consisting of a polymer and co-polymer.

40. The cable assembly according to claim 38 in which said continuous resistive link filament means is an electrically conductive ceramic material with an excess of electrically conductive material.

41. The cable assembly according to claim 38 in which said continuous resistive link filament means is a plurality of series-connected discrete high precision tolerance low temperature coefficient of resistance resistors.

42. The cable assembly according to claim 36 in which contains and includes an optical radiant energy transmission medium means for containing, routing and conducting optical radiant energy across said high voltage gradient.

43. The cable assembly according to claim 42 in which said optical radiant energy transmission medium means comprises an optical radiant energy conducting optical fiber bundle assembled from a plurality of optical fibers.

44. The cable assembly according to claim 43 in which said optical radiant energy transmission medium means comprises an optical radiant energy conducting cast polymer body.