Electrical power line and substation monitoring apparatus and systems

• US 4,777,381 A
• Filed: 05/11/1987
• Issued: 10/11/1988
• Est. Priority Date: 04/13/1983
• Status: Expired due to Term

• Current Assignee: Undersground Systems, Inc.
• Original Assignee: Roosevelt A. Fernandes
• Inventors: Fernandes, Roosevelt A.
• Primary Examiner(s): Shoop, Jr., William M.
• Assistant Examiner(s): IP, SHIK LUEN PAUL
• Application Number:
  US07/048,582
• Time in Patent Office: 519 Days
• Field of Search: 307/64, 307/66, 307/48, 307/52, 307/128, 307/129, 307/130, 307/131, 307/87, 324/51, 324/ 78 R, 324/126, 324/127, 340/870.11, 340/870.16, 340/870.17, 340/870.28, 340/870.37, 340/870.38, 340/870.39, 361/44, 361/45, 361/57, 361/56, 361/63, 361/64, 361/65, 361/72, 361/79, 361/78, 361/86, 361/87, 361/88, 361/90, 361/91, 361/92, 361/93, 310/308, 310/309, 310/310, 290/44, 290/45
• US Class Current: 307/64
• CPC Class Codes: G01K 1/024 for remote indication
• CPC Class Codes: G01K 1/143 for measuring surface temperatures
• CPC Class Codes: G01R 15/142 Arrangements for simultaneous measurements of several parameters employing techniques covered by groups G01R15/14 - G01R15/26
• CPC Class Codes: G01R 15/26 using modulation of waves other than light, e.g. radio or acoustic waves
• CPC Class Codes: G01R 23/16 Spectrum analysis; Fourier analysis
• CPC Class Codes: H01J 13/00 Discharge tubes with liquid-pool cathodes, e.g. metal-vapour rectifying tubes
• CPC Class Codes: H02J 13/00022 using wireless data transmission
• CPC Class Codes: H02J 13/00034 the elements or equipment being or involving an electric power substation
• 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

Abstract

Disclosed herein are individual sensor modules for mounting directly upon energized electrical power conductors and systems employing such modules, with principal emphasis upon the provision of both data transmitting and receiving means in each sensor module and at an associated ground station. The modules sense the instantaneous values of all parameters necessary to perform complete metering functions and, in one embodiment, are synchronized by a signal transmitted from the ground station and received by all modules so that the values are measured simultaneously on all conductors at a substation. The signals are transmitted by the modules in a time-synchronized manner and are in a condition for use directly by the ground station microprocessor. In another embodiment, data transmissions by a plurality of modules is synchronized to avoid data collisions by self-contained means within each module, requiring no synchronizing signal from the ground station. Also disclosed is a reliable battery back-up system, requiring essentially no removal and/or replacement of batteries for recharging, for providing power to the module electronics when there is little or no current flowing through the associated conductor.

Claims

1. A device for monitoring at least one parameter of a power transmission line, including means for sensing values of said parameter, means for processing said values, means for periodically transmitting said values, means for deriving energy from said transmission line for powering said processing means and transmitting means, energy storage means for powering said processing means and transmitting means, means for sensing voltage on said transmission line with no current in said transmission lie and for providing a signal indicating the no current condition, and means responsive to said indicating signal being present for a predetermined time period for reducing the frequency of periodic transmissions.

2. A device according to claim 1 including control means responsive to said indicating signal being present for causing said processing means and transmitting means to be powered by said energy storage means.

3. A device mountable on and removable from an energized electrical power conductor for measuring at least one parameter of said conductor, said device comprising:

(a) housing means having a metallic outer skin and defining an enclosed space;

(b) means carried within said enclosed space for processing values of said parameters;

(c) means carried within said enclosed space for periodically transmitting signals commensurate with said values;

(d) primary and secondary power supply means within said enclosed space for alternatively providing power to said processing and transmitting means;

(e) means for mounting said housing means to said conductor, whereby all of said processing, transmitting and power supply means operate essentially at the potential of said conductor;

(f) said metallic outer skin being so constructed that no continuous conducting loops surround said enclosed space; and

(g) means for causing said primary power supply means to provide power to said processing and transmitting means when adequate power is available from said primary power supply means, and for causing said secondary power supply means to provide power to said processing and transmitting means when power from said primary power supply means is inadequate.

4. A device according to claim 3 in which said primary supply means derives energy from power flowing through said conductor and said secondary supply means is an energy storage device.

5. A device according to claim 4 including means for sensing voltage on said conductor with no current in said conductor and for providing a signal indicating the no current condition.

6. A device according to claim 5 including means responsive to said indicating signal being present for a predetermined period for reducing the frequency of transmission.

7. A device according to claim 6 including means for electrostatically float charging said energy storage device when no current is flowing through said conductor, and data is not being transmitted from said device.

8. A device according to claim 3 wherein said parameter is voltage.

9. A device according to claim 8 including means for measuring, processing and transmitting values of harmonics of said parameter.

10. The invention according to claim 3 wherein said secondary power supply means is an energy storage device, and further including means for float charging said energy storage device from electrostatic energy on said conductor.

11. A device according to claim 10 wherein said means for float charging said energy storage device includes a metal housing of said device for electrostatic current collection.

12. A device according to claim 11 wherein said means for float charging further includes means for increasing the effective surface area of said housing thereby increasing said electrostatic current collection.

13. A device according to claim 12 wherein said means for increasing the effective surface area of said housing includes at least one metallized tubular rod attached to said housing at one end and terminating in a metallized sphere at the other end.

14. The invention according to claim 3 wherein said secondary power supply means is an energy storage device, and further including means for float charging said energy storage device from electromagnetic energy on said conductor.

15. The invention according to claim 3 wherein said housing means is conductively isolated, at least for frequencies below the highest frequency of conductor voltage to be measured, from said conductor, whereby the surface of said housing continuously collects the charging current due to the electrostatic field associated with said conductor, and further including means connected between said conductor and said housing means for measurement of conductor voltage from said charging current.

16. The invention according to claim 3 and further including means contained within said enclosed space for continuously sensing the current through said conductor over the entire load range of the power system circuit including said conductor.

17. The invention according to claim 16 and further including means for continuously sensing the voltage on said conductor, and for establishing the phase relationship between said sensed values of conductor voltage and conductor current.

18. The invention according to claim 17 and further including means carried within said enclosed space for identifying, processing and storing said sensed values of conductor voltage, conductor current and established phase relationship.

19. The invention according to claim 18 wherein said transmitting means comprises means for transmitting a sequence of encoded signals commensurate with each of said sensed values and including said established phase relationship and sensor module identification.