System for detecting a falling electric power conductor and related methods

• US 9,413,156 B2
• Filed: 07/26/2013
• Issued: 08/09/2016
• Est. Priority Date: 07/27/2012
• Status: Active Grant

• Current Assignee: San Diego Gas & Electric Company (Sempra Energy)
• Original Assignee: San Diego Gas & Electric Company (Sempra Energy)
• Inventors: O'Brien, William, Udren, Eric A.
• Primary Examiner(s): Kaplan, Hal
• Application Number:
  US13/952,433
• Publication Number:
  US 20140028116A1
• Time in Patent Office: 1,110 Days
• Field of Search: 307/125, 307/130, 307/131
• US Class Current: 1/1
• CPC Class Codes: H02H 3/02 Details
• CPC Class Codes: H02H 3/04 with warning or supervision in addition to disconnection, e.g. for indicating that protective apparatus has functioned watching of pilot wires H02H1/0084; protection of protective arrangements H02H7/008; indication of the state of electronic switches H03K17/18
• CPC Class Codes: H02H 3/26 responsive to difference between voltages or between currents; responsive to phase angle between voltages or between currents
• CPC Class Codes: H02H 3/265 responsive to phase angle between voltages or between currents
• CPC Class Codes: H02H 3/32 involving comparison of the voltage or current values at corresponding points in different conductors of a single system, e.g. of currents in go and return conductors
• CPC Class Codes: H02H 3/325 involving voltage comparison H02H3/347 takes precedence
• CPC Class Codes: H02H 3/353 involving comparison of phase voltages
• CPC Class Codes: H02H 3/38 responsive to both voltage and current; responsive to phase angle between voltage and current
• CPC Class Codes: H02H 3/422 using homopolar quantities
• CPC Class Codes: H02H 3/44 responsive to the rate of change of electrical quantities
• CPC Class Codes: H02H 3/46 responsive to frequency deviations
• CPC Class Codes: H02H 3/48 responsive to loss of synchronism
• CPC Class Codes: H02H 7/261 involving signal transmission between at least two stations transmission of signals in general H02H1/0061
• CPC Class Codes: H02H 7/263 involving transmissions of measured values comparison of currents or voltages using pilot wires H02H3/30
• CPC Class Codes: H02H 7/28 for meshed systems
• CPC Class Codes: Y02E 40/70 Smart grids as climate change mitigation technology in the energy generation sector
• 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 10/22 Flexible AC transmission systems [FACTS] or power factor or reactive power compensating or correcting units

Abstract

Methods and systems for detecting a falling power line in a power transmission or distribution system are described. Electrical measurements at various points in the power distribution system are used to detect changes in a power line indicating that the conductor has broken or become disconnected. Upon detection, control mechanisms are used to deenergize the conductor while the conductor is falling and/or before it contacts the ground.

Claims

1. A system for detecting a falling conductor in a power transmission or distribution system comprising:

a conductor carrying voltage,

an electrical measurement device in electrical communication with the conductor to measure an electrical characteristic of the conductor at a location in the power transmission or distribution system to determine whether the measured electrical characteristic is indicative of the conductor separating from the power transmission or distribution system;

a communication device to send a signature indicative of the falling conductor to a control device; and

wherein the control device is programmed to send a signal to activate one or more switching devices to deenergize the falling conductor in a time before the conductor contacts a ground surface.

2. The system of claim 1, wherein the electrical characteristic is voltage.

3. The system of claim 1, wherein the electrical characteristic is current.

4. The system of claim 1, wherein the measured electrical characteristic is below a predetermined threshold value, which is indicative of a falling conductor.

5. The system of claim 1, wherein the electrical measurement device is located on a fused branch.

6. The system of claim 5, wherein the electrical measurement device detects a falling conductor when the measured electrical characteristic indicates a decreased voltage for a predetermined period of time.

7. The system of claim 1, wherein the communication device is at least one of a wired communications network, a wireless network, a radio network, a set of links comprising a network, a packet-based or Ethernet data network, and a time-division multiplexed (TDM) serial network.

8. The system of claim 1, wherein the control device includes at least one of a circuit breaker, a distribution recloser, and a circuit switcher.

9. The system of claim 1, wherein the electrical characteristic is one of a phase relationship and time behavior for determining a measurement just before an apparent event and a measurement just after the apparent event.

10. A method for detecting a falling conductor in a power distribution system, the method comprising:

detecting a falling conductor based on an electrical signature measured at a location on the circuit experiencing the falling conductor; and

transmitting the electrical signature or a status change signal indicative of a line break signal to one or more control devices in locations where they can deenergize the falling conductor before the falling conductor contacts a ground surface.

11. The method of claim 10, further comprising activating one or more circuit breakers located where they can deenergize the falling conductor before the falling conductor contacts the ground surface.

12. The method of claim 10, wherein any of the control devices is a recloser, a switch or a circuit breaker.

13. The method of claim 10, wherein the transmitting is performed by a control device at a substation.

14. A system for detecting a problem conductor with an electrical measurement device on the circuit comprising:

a sensor device to measure an electrical signature at a location in a power distribution system and to determine whether the measured electrical signature is below a predetermined threshold;

a computing device to generate a status change signal based on the measured electrical signature being below the predetermined threshold; and

a communication device to send the status change signal to a control device, which is located where it is able to disconnect the portion of the system for which the sensor device measures the signature.

15. The system of claim 14, wherein the predetermined threshold is indicative of a falling conductor and the control device receives the status change signal and controls one or more switching devices to disconnect power to the affected portion of the system before the falling conductor contacts a ground surface.

16. The system of claim 14, wherein the sensor device comprises a protective relay.

17. The system of claim 14, wherein the sensor device comprises a recloser control device.

18. The system of claim 14, wherein the sensor device comprises a phasor measurement unit.

19. A system for detecting a problem conductor with a voltage sensor on a circuit comprising:

a voltage sensor device to measure a voltage at a location in a power distribution system and to generate a status change signal when the measured voltage is below a predetermined threshold voltage value;

a communication device coupled to the voltage sensor device to at least one of receive and transmit the status change signal; and

a controller to receive the status change signal from the communication device and to control one or more switching devices to disconnect power to a portion of the system of the problem conductor.

20. The system of claim 19, wherein the status change signal is indicative of a falling conductor and the controller receives the status change signal and controls one or more switching devices to disconnect power to the affected portion of the system before the falling conductor contacts a ground surface.

21. The system of claim 19, wherein the voltage sensor comprises a protective relay.

22. The system of claim 19, wherein the voltage sensor comprises a recloser control device.

23. The system of claim 19 wherein the voltage sensor comprises a phasor measurement unit.

24. A control box for use in at least one of an electrical transmission system and a distribution system comprising:

a housing having an enclosure and enclosing a plurality of electronic circuitries;

a programmable processor located in the housing and programmed to;

receive a status change signal from a communication device;

evaluate whether the status change signal represents a problem conductor; and

emit a disconnect signal to one or more switching devices to deenergize the affected portion of the system before a problem conductor contacts the ground; and

one or more ports associated with the housing for connecting wires, cables, input devices, output devices, or combinations thereof.

25. The control box of claim 24, further comprising a communication module for sending and receiving signals or data.

26. A control box for use in at least one of an electrical transmission system and a distribution system comprising:

a housing having an enclosure and enclosing a plurality of electronic circuitries;

a programmable processor located in the housing and programmed to;

perform (a) a comparison function of a signal from a first location at time one and a signal from the first location at time two or (b) a comparison function of a signal from a first location and a signal from a second location, the second location being in any direction with respect to the first location;

evaluate changes at time one and time two or changes between the first location and the second location to determine if a problem conductor is present; and

emit a disconnect signal to one or more switching devices to deenergize the affected portion of the system before a problem conductor contacts the ground; and

one or more ports associated with the housing for connecting wires, cables, input devices, output devices, or combinations thereof.

27. The control box of claim 26, further comprising a communication module for sending and receiving signals or data.

28. A system comprising a first control box for monitoring signals and a second control box for controlling signals in at least one of an electrical transmission network and a distribution network, the system comprising:

a first housing having an enclosure and enclosing a plurality of electronic circuitries;

a programmable processor located in the first housing programmed to;

receive a status change signal from a communication device;

evaluate whether the status change signal represents a problem conductor; and

emit an affirmative signal of a problem conductor; and

one or more ports associated with the first housing for connecting wires, cables, input devices, output devices, or combinations thereof; and

a second housing having an enclosure and enclosing a plurality of electronic circuitries;

a programmable processor located in the second housing programmed to;

receive an affirmative signal of a problem conductor; and

emit a disconnect signal to one or more switching devices to deenergize the affected portion of the system before a problem conductor contacts the ground; and

one or more ports associated with the second housing for connecting wires, cables, input devices, output devices, or combinations thereof.

29. The system of claim 28, wherein the first box and the second box communicate with one another wirelessly or through connections with the one or more ports.