Identification of electrical grid phase information for end-points in a grid network

• US 8,712,711 B2
• Filed: 07/21/2011
• Issued: 04/29/2014
• Est. Priority Date: 07/21/2011
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Nayar, Nitin, Taft, Jeffrey D., Yadav, Navindra
• Primary Examiner(s): Le, John H
• Application Number:
  US13/187,765
• Publication Number:
  US 20130024149A1
• Time in Patent Office: 1,013 Days
• Field of Search: 702/61, 702/72, 702/79, 702/89, 702/106, 702/122, 324/66, 324/86, 324/142, 327/116, 327/153, 327/276, 329/304, 329/306, 375/142, 375/362, 455/67.15
• US Class Current: 702/72
• CPC Class Codes: G01R 29/18 Indicating phase sequence; Indicating synchronism
• CPC Class Codes: H02J 13/00006 characterised by information or instructions transport means between the monitoring, controlling or managing units and monitored, controlled or operated power network element or electrical equipment
• CPC Class Codes: H02J 13/00034 the elements or equipment being or involving an electric power substation
• CPC Class Codes: H02J 3/26 Arrangements for eliminating or reducing asymmetry in polyphase networks
• CPC Class Codes: Y02E 40/50 Arrangements for eliminating or reducing asymmetry in polyphase networks
• CPC Class Codes: Y02E 60/00 Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
• CPC Class Codes: Y04S 40/12 characterised by data transport means between the monitoring, controlling or managing units and monitored, controlled or operated electrical equipment

Abstract

In one embodiment, a requesting device (e.g., head-end application) requests a phase-related response from an end-point that does not know its phase in a polyphase power source system. In response, the requesting device receives the phase-related response from the end-point, where the response relays an identification of the end-point and related phase information without indicating an actual phase of the end-point, e.g., on which power-line is a response generated or at which time is a zero-crossing of the power source'"'"'s waveform. The phase information of the phase-related response may then be correlated to a known phase of a known-phase device, such that the actual phase of the end-point may be identified based on the correlation.

Claims

1. A method, comprising:

requesting a phase-related response from an end-point that does not know its phase in a polyphase power source system;

receiving the phase-related response from the end-point, the phase-related response configured to relay an identification of the end-point and related phase information without indicating an actual phase of the end-point;

correlating the phase information of the phase-related response to a known phase of a known-phase device; and

identifying the actual phase of the end-point based on the correlation, wherein

the phase-related response is a message transmitted on a particular power-line of the polyphase power source system, the related phase information of the phase-related response being the fact that the message was transmitted on the particular power-line.

2. The method as in claim 1, further comprising:

correlating the phase information by determining a particular known-phase device through which the phase-related response was received over the corresponding particular power-line; and

identifying the actual phase of the end-point as the known phase of the particular known-phase device.

3. The method as in claim 2, further comprising:

determining a hierarchy of end-points and known-phase devices in the polyphase power source system based on reception of phase-related responses on power-lines through particular devices.

4. The method as in claim 1, wherein the related phase information within the phase-related response includes a timestamp corresponding to zero-crossing timing of a particular power-line of the polyphase power source system on which the end-point is located, the method further comprising:

correlating the phase information by determining a particular known-phase device having a corresponding timestamp for its zero-crossing timing; and

identifying the actual phase of the end-point as the known phase of the particular known-phase device.

5. The method as in claim 4, wherein the timestamp is based on shared network timing information.

6. The method as in claim 1, further comprising:

maintaining a security relationship with the end-point, wherein the phase-related response carries a security credential.

7. The method as in claim 1, wherein requesting the phase-related response comprises:

transmitting an out-of-band (OOB) request to the end-point, wherein the OOB request is transmitted on a transmission medium other than a power-line from which the end-point receives power.

8. The method as in claim 1, further comprising:

determining a first satellite-based global position of the end-point;

determining a second satellite-based global position of a non-communicating power device;

correlating a co-location between the first and second satellite-based global positions; and

identifying an assumed phase of the non-communicating power device as the actual phase of the co-located end-point.

9. A tangible, non-transitory, computer-readable media having software encoded thereon, the software when executed by a processor on a device in a computer network operable to:

request a phase-related response from an end-point that does not know its phase in a polyphase power source system;

receive the phase-related response from the end-point, the phase-related response configured to relay an identification of the end-point and related phase information without indicating an actual phase of the end-point;

correlate the phase information of the phase-related response to a known phase of a known-phase device; and

identify the actual phase of the end-point based on the correlation, wherein

the phase-related response is a message transmitted on a particular power-line of the polyphase power source system, the related phase information of the phase-related response being the fact that the message was transmitted on the particular power-line.

10. The computer-readable media as in claim 9, wherein the software when executed is further operable to:

correlate the phase information by determining a particular known-phase device through which the phase-related response was received over the corresponding particular power-line; and

identify the actual phase of the end-point as the known phase of the particular known-phase device.

11. The computer-readable media as in claim 9, wherein the related phase information within the phase-related response includes a timestamp corresponding to zero-crossing timing of a particular power-line of the polyphase power source system on which the end-point is located, and wherein the software when executed is further operable to:

correlate the phase information by determining a particular known-phase device having a corresponding timestamp for its zero-crossing timing; and

identify the actual phase of the end-point as the known phase of the particular known-phase device.

12. The computer-readable media as in claim 9, wherein the software when executed to request the phase-related response is further operable to:

transmit an out-of-band (OOB) request to the end-point, wherein the OOB request is transmitted on a transmission medium other than a power-line from which the end-point receives power.

13. The computer-readable media as in claim 9, wherein the software when executed is further operable to:

determine a first satellite-based global position of the end-point;

determine a second satellite-based global position of a non-communicating power device;

correlate a co-location between the first and second satellite-based global positions; and

identify an assumed phase of the non-communicating power device as the actual phase of the co-located end-point.

14. A method, comprising:

receiving a request for a phase-related response at an end-point that does not know its phase in a polyphase power source system; and

returning the phase-related response from the end-point, the phase-related response configured to relay an identification of the end-point and related phase information without indicating an actual phase of the end-point, wherein

the phase-related response is a message transmitted on a particular power-line of the polyphase power source system, the related phase information of the phase-related response being the fact that the message was transmitted on the particular power-line.

15. The method as in claim 14, wherein returning the phase-related response comprises:

including a timestamp in the related phase information within the phase-related response, the timestamp corresponding to zero-crossing timing of a particular power-line of the polyphase power source system on which the end-point is located.

16. The method as in claim 14, further comprising:

maintaining a security relationship with a requestor of the phase-related response, wherein the phase-related response carries a security credential.

17. The method as in claim 14, wherein receiving the request for the phase-related response comprises:

receiving an out-of-band (OOB) request at the end-point, wherein the OOB request is transmitted on a transmission medium other than a power-line from which the end-point receives power.

18. An apparatus, comprising:

a power supply adapted to receive an alternating-current (AC) waveform of an electrical power source, the power source being part of a polyphase power source system, wherein the apparatus does not know its phase in the polyphase power source system;

a network interface adapted to communicate in a computer network;

a processor coupled to the network interface and adapted to execute one or more processes; and

a memory configured to store a process executable by the processor, the process when executed operable to;

receive a request for a phase-related response from a requestor; and

return the phase-related response to the requestor, the phase-related response configured to relay an identification of the apparatus and related phase information without indicating an actual phase of the apparatus, wherein

the phase-related response is a message transmitted on a particular power-line of the polyphase power source system, the related phase information of the phase-related response being the fact that the message was transmitted on the particular power-line.

19. The apparatus as in claim 18, wherein the process when executed to return the phase-related response is further operable to:

include a timestamp in in the related phase information within the phase-related response, the timestamp corresponding to zero-crossing timing of a particular power-line of the polyphase power source system on which the apparatus is located.

20. The apparatus as in claim 18, wherein the process when executed is further operable to:

maintain a security relationship with the requestor of the phase-related response, wherein the phase-related response carries a security credential.

21. The apparatus as in claim 18, wherein the process when executed to receive the request for the phase-related response is further operable to:

receive an out-of-band (OOB) request, wherein the OOB request is transmitted on a transmission medium other than a power-line from which the apparatus receives power.