METHOD AND SYSTEM FOR CURRENT DIFFERENTIAL PROTECTION

• US 20140169157A1
• Filed: 12/14/2012
• Published: 06/19/2014
• Est. Priority Date: 12/14/2012
• Status: Active Grant

• Current Assignee: GE Infrastructure Technology, LLC (GE Vernova, Inc.)
• Original Assignee: General Electric Company
• Inventors: Pan, Yan, Premerlani, William James
• Granted Patent: US 8,942,108 B2
• Time in Patent Office: Days
• US Class Current: 370/228
• CPC Class Codes: H02H 1/0061 concerning transmission of signals transmission of measured quantities or switching orders; sectionalised protection involving signal transmission between at least two stations H02H7/261; comparison of the voltage or current values at two spaced portions of a single system H02H3/28; transferring the output of a sensing member to another variable G01D5/00; electrical measuring arrangements using modulation of electromagnetic waves, e.g. light beams G01R15/24, G01R15/26
• CPC Class Codes: H02H 3/305 involving current comparison
• CPC Class Codes: H02J 13/00 Circuit arrangements for providing remote indication of network conditions, e.g. an instantaneous record of the open or closed condition of each circuitbreaker in the network; Circuit arrangements for providing remote control of switching means in a power distribution network, e.g. switching in and out of current consumers by using a pulse code signal carried by the network
• CPC Class Codes: H02J 13/00017 using optical fiber
• CPC Class Codes: H02J 13/0004 involved in a protection system
• CPC Class Codes: H04J 3/0638 Clock or time synchronisation among nodes; Internode synchronisation synchronization for ring networks H04L12/422; data switching networks with synchronous transmission H04L12/43
• CPC Class Codes: H04J 3/0641 Change of the master or reference, e.g. take-over or failure of the master
• CPC Class Codes: H04L 12/40 Bus networks
• CPC Class Codes: H04L 12/4035 in which slots of a TDMA packet structure are assigned based on a contention resolution carried out at a master unit TDM/TDMA multiplex systems per se H04J3/1694; hybrid switching systems H04L12/64
• CPC Class Codes: H04L 41/0668 by dynamic selection of recovery network elements, e.g. replacement by the most appropriate element after failure
• CPC Class Codes: H04L 41/0686 Additional information in the notification, e.g. enhancement of specific meta-data
• CPC Class Codes: H04L 41/12 Discovery or management of network topologies

Abstract

A differential protection system is provided. The differential protection system includes a local terminal configured to be communicatively coupled directly or indirectly with at least two remote terminals via at least three communication links to form a ring topology or a mesh topology. The differential protection system further includes a controller comprising a communication link decision unit and a clock unit associated with the local terminal. The communication link decision unit is configured to determine some of the at least three communication links as virtually disconnected such that the ring topology or the mesh topology is configured to be converted to a daisy chain topology. The clock unit is configured to time synchronize the local terminal with at least one of the at least two remote terminals when the local terminal and the at least two remote terminals are configured in the daisy chain topology.

Claims

1. A system, comprising:

a local terminal configured to be communicatively coupled directly or indirectly with at least two remote terminals via at least three communication links to form one of a ring topology or a mesh topology; and

a controller comprising;

a communication link decision unit configured to determine at least one of the at least three communication links as virtually disconnected such that one of the ring topology or the mesh topology of the local terminal and the at least two remote terminals is configured to be converted to a daisy chain topology, and

a clock unit associated with the local terminal, wherein the clock unit is configured to time synchronize the local terminal with at least one of the at least two remote terminals when the local terminal and the at least two remote terminals are configured in the daisy chain topology.

2. The system of claim 1, wherein the daisy chain topology comprises:

at least two terminals from;

the local terminal and the at least two remote terminals configured to act as opposing end terminals of the daisy chain topology, and

terminals other than the opposing end terminals configured to act as intermediate terminals of the daisy chain topology.

3. The system of claim 2, wherein when the local terminal is configured to act as one of the opposing end terminals of the daisy chain topology, the clock unit is configured to:

receive timing information from a neighboring terminal of the local terminal, wherein the neighboring terminal comprising one of the at least two remote terminals, and

time synchronize the local terminal with the neighboring terminal based on the received timing information from the neighboring terminal.

4. The system of claim 2, wherein when the local terminal is configured to act as one of the intermediate terminals of the daisy chain topology, the clock unit is configured to:

receive timing information from two neighboring terminals of the local terminal, wherein the two neighboring terminals comprising two of the at least two remote terminals,

determine time delays between the local terminal and the two neighboring terminals based on the received timing information, and

calculate an average of the determined time delays between the local terminal and the two neighboring terminals so as to time synchronize the local terminal.

5. The system of claim 1, wherein the communication link decision unit is configured to determine the at least one of the at least three communication links as virtually disconnected based on a first defined priority list.

6. The system of claim 1, wherein the controller further comprises a master determination unit configured to determine one terminal from:

the local terminal and the at least two remote terminals as a first master terminal, and further configured to define terminals other than the first master terminal as slave terminals, wherein the daisy chain topology comprising the first master terminal and the slave terminals.

7. The system of claim 6, wherein when the local terminal is the slave terminal, the clock unit is configured to:

receive timing information from a neighboring terminal of the local terminal nearest to the first master terminal, when the neighboring terminal of the local terminal nearest to the first master terminal comprising one of the at least two remote terminals, and

time synchronize the local terminal with the neighboring terminal of the local terminal nearest to the first master terminal based on the received timing information from the neighboring terminal of the local terminal nearest to the first master terminal.

8. The system of claim 6, wherein when the local terminal is the slave terminal, the clock unit is configured to:

receive timing information from the first master terminal when the first master terminal is a neighboring terminal of the local terminal, wherein the first master terminal comprising one of the at least two remote terminals, and

time synchronize the local terminal with the first master terminal based on the received timing information from the first master terminal.

9. The system of claim 6, wherein the master determination unit is configured to determine the first master terminal based on a second defined priority list.

10. The system of claim 6, wherein the communication link decision unit is further configured to:

receive data indicating the determined first master terminal from the master determination unit, and

determine the virtually disconnected communication link based on the received data.

11. The system of claim 6, wherein the master determination unit is further configured to:

receive data indicating the virtually disconnected communication link from the communication link decision unit, and

determine the first master terminal based on the received data.

12. The system of claim 6, further comprising a mapping unit configured to store a mapping between the first master terminal and the virtually disconnected communication link.

13. The system of claim 1, further comprising a message communication unit configured to exchange one or more first messages between the local terminal and the at least two remote terminals, and among the at least two remote terminals, wherein the one or more first messages comprise:

a first data indicating at least one of the virtually disconnected communication link or a first master terminal, and

at least one of a first link identification (ID) or a first master ID.

14. The system of claim 1, further comprising a fault detection unit to detect a fault in at least one communication link of the at least three communication links.

15. The system of claim 14, wherein the communication link decision unit is further configured to:

receive an indication from the fault detection unit for the fault in the at least one communication link,

define the determined virtually disconnected communication link as an operational link, when the at least one faulty communication link is different from the determined virtually disconnected communication link, and

define the at least one communication link as the at least one faulty communication link based on the indication received from the fault detection unit.

16. The system of claim 15, further comprising a message communication unit configured to exchange one or more second messages between the local terminal and the at least two remote terminals, and among the at least two remote terminals, wherein the one or more second messages comprise:

a second data indicating at least one of the at least one faulty communication link or a second master terminal, and

at least one of a second link ID or a second master ID.

17. The system of claim 15, further comprising a master determination unit configured to replace a first master terminal with a second master terminal, when the at least one faulty communication link is different from the determined virtually disconnected communication link.

18. A method, comprising:

providing one of a ring topology or a mesh topology comprising a local terminal and at least two remote terminals, wherein the local terminal is configured to be communicatively coupled directly or indirectly with the at least two remote terminals via at least three communication links;

determining at least one of the at least three communication links as virtually disconnected such that one of the ring topology or the mesh topology of the local terminal and the at least two remote terminals is configured to be converted to a daisy chain topology; and

synchronizing time of the local terminal with at least one of the at least two remote terminals when the local terminal and the at least two remote terminals are configured in the daisy chain topology.

19. The method of claim 18, wherein the daisy chain topology comprises:

at least two terminals from;

the local terminal and the at least two remote terminals configured to act as opposing end terminals of the daisy chain topology, and

terminals other than the opposing end terminals configured to act as intermediate terminals of the daisy chain topology.

20. The method of claim 19, wherein when the local terminal is configured to act as one of the opposing end terminals of the daisy chain topology, the synchronizing comprises:

receiving timing information from a neighboring terminal of the local terminal, wherein the neighboring terminal comprising one of the at least two remote terminals, and

synchronizing time of the local terminal with the neighboring terminal based on the received timing information from the neighboring terminal.

21. The method of claim 19, wherein when the local terminal is configured to act as one of the intermediate terminals of the daisy chain topology, the synchronizing comprises:

receiving timing information from two neighboring terminals of the local terminal, wherein the two neighboring terminals comprising two of the at least two remote terminals,

determining time delays between the local terminal and the two neighboring terminals based on the received timing information, and

calculating an average of the determined time delays between the local terminal and the two neighboring terminals.

22. The method of claim 18, wherein the at least one of the at least three communication links is determined as virtually disconnected based on a first defined priority list.

23. The method of claim 18, further comprising:

determining one terminal from;

the local terminal and the at least two remote terminals as a first master terminal, and

defining terminals other than the first master terminal as slave terminals, wherein the daisy chain topology comprising the first master terminal and the slave terminals.

24. The method of claim 23, wherein when the local terminal is the slave terminal, the synchronizing comprises:

receiving timing information from a neighboring terminal of the local terminal nearest to the first master terminal, when the neighboring terminal of the local terminal nearest to the first master terminal comprising one of the at least two remote terminals, and

synchronizing time of the local terminal with the neighboring terminal of the local terminal nearest to the first master terminal based on the received timing information from the neighboring terminal of the local terminal nearest to the first master terminal.

25. The method of claim 23, wherein when the local terminal is the slave terminal, the synchronizing comprises:

receiving timing information from the first master terminal when the first master terminal is a neighboring terminal of the local terminal, wherein the first master terminal comprising one of the at least two remote terminals, and

synchronizing time of the local terminal with the first master terminal based on the received timing information from the first master terminal.

26. The method of claim 23, wherein the first master terminal is determined based on a second defined priority list.

27. The method of claim 23, wherein the determining comprises:

receiving data indicating the determined first master terminal, and

determining the virtually disconnected communication link based on the received data.

28. The method of claim 23, wherein determining the first master terminal comprises:

receiving data indicating the virtually disconnected communication link, and

determining the first master terminal based on the received data.

29. The method of claim 23, further comprising storing a mapping between the first master terminal and the virtually disconnected communication link.

30. The method of claim 18, further comprising exchanging one or more first messages between the local terminal and the at least two remote terminals, and among the at least two remote terminals, wherein the one or more first messages comprise:

a first data indicating at least one of the virtually disconnected communication link or a first master terminal, and

at least one of a first link ID or a first master ID.

31. The method of claim 18, further comprising detecting a fault in at least one communication link of the at least three communication links.

32. The method of claim 31, further comprising:

receiving an indication for the fault in the at least one communication link,

defining the determined virtually disconnected communication link as an operational link, when the at least one faulty communication link is different from the determined virtually disconnected communication link, and

defining the at least one communication link as the at least one faulty communication link based on the received indication.

33. The method of claim 32, further comprising exchanging one or more second messages between the local terminal and the at least two remote terminals, and among the at least two remote terminals, wherein the one or more second messages comprise:

a second data indicating at least one of the at least one faulty communication link or a second master terminal, and

at least one of a second link ID or a second master ID.

34. The method of claim 32, further comprising:

replacing a first master terminal with a second master terminal, when the at least one faulty communication link is different from the determined virtually disconnected communication link,

receiving timing information from a neighboring terminal of the local terminal nearest to the second master terminal, when the neighboring terminal of the local terminal nearest to the second master terminal comprising one of the at least two remote terminals, and

synchronizing time of the local terminal with the neighboring terminal of the local terminal nearest to the second master terminal based on the received timing information from the neighboring terminal of the local terminal nearest to the second master terminal.

35. The method of claim 32, further comprising:

replacing a first master terminal with a second master terminal, when the at least one faulty communication link is different from the determined virtually disconnected communication link,

receiving timing information from the second master terminal when the second master terminal is a neighboring terminal of the local terminal, wherein the second master terminal comprising one of the at least two remote terminals, and

synchronizing time of the local terminal with the second master terminal based on the received timing information from the second master terminal.

36. A non-transitory computer-readable medium comprising computer-readable instructions of a computer program that, when executed by a processor, cause the processor to perform a method, the method comprising:

providing one of a ring topology or a mesh topology comprising a local terminal and at least two remote terminals, wherein the local terminal is configured to be communicatively coupled directly or indirectly with the at least two remote terminals via at least three communication links;

determining at least one of the at least three communication links as virtually disconnected such that one of the ring topology or the mesh topology of the local terminal and the at least two remote terminals is configured to be converted to a daisy chain topology; and

synchronizing time of the local terminal with at least one of the at least two remote terminals when the local terminal and the at least two remote terminals are configured in the daisy chain topology.