IDENTIFICATION OF ELECTRICAL GRID PHASE INFORMATION FOR END-POINTS IN A GRID NETWORK

• US 20130024149A1
• Filed: 07/21/2011
• Published: 01/24/2013
• 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
• Granted Patent: US 8,712,711 B2
• Time in Patent Office: Days
• 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.

2. The method as in claim 1, 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, the method 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 is 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.

18. The method as in claim 1, 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.

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.

10. The computer-readable media as in claim 9, 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, and 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 is 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

return 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.

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

transmitting a message 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.

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

including the related phase information within the phase-related response as 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.

17. 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.

19. 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.

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

transmit a message 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.

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

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

22. The apparatus as in claim 19, 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.

23. The apparatus as in claim 19, 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.