Systems and methods for distributed series compensation of power lines using passive devices

• US 7,835,128 B2
• Filed: 01/30/2006
• Issued: 11/16/2010
• Est. Priority Date: 01/31/2005
• Status: Active Grant

• Current Assignee: Georgia Tech Research Corporation (University System of Georgia)
• Original Assignee: Georgia Tech Research Corporation (University System of Georgia)
• Inventors: Johal, Harjeet, Divan, Deepakraj Malhar
• Primary Examiner(s): Jackson; Stephen W
• Assistant Examiner(s): BROOKS, ANGELA D
• Application Number:
  US11/815,052
• Publication Number:
  US 20080310069A1
• Time in Patent Office: 1,751 Days
• Field of Search: 361/93, 361/268, 361/58, 307/112, 307/98, 340/870.27
• US Class Current: 361/93.9
• CPC Class Codes: H02H 9/02 responsive to excess current current limitation for voltage regulators G05F1/573; disconnection after limiting H02H3/025
• CPC Class Codes: H02J 3/1807 using series compensators
• CPC Class Codes: Y02E 40/30 Reactive power compensation

Abstract

Systems and methods for implementing line overload control via providing distributed series impedance are disclosed. One system, amongst others, comprises at least one distributed series reactor (DSR). Each DSR comprises a single turn transformer (SST) comprising two split-core sections (132), a winding (120), and an air-gap (138), the air-gap designed such that a magnetizing inductance is produced when the two split-core sections (132) are clamped around a conductor (108). Each DSR further comprises a contact switch (122) that short circuits the winding when the contact switch (122) is in a closed condition, a power supply (128) that derives power from conductor line current, and a controller (130) configured to open the contact switch when the conductor line current reaches a predetermined value, thus causing insertion of the magnetizing inductance into the conductor. The controller (130) may be further configured to close the contact switch (122) when the conductor line current drops below the predetermined value.

Claims

1. A system for implementing line overload control via providing distributed series impedance, the system comprising:

at least one distributed series reactor (DSR) configured to insert a passive inductance into a conductor, the at least one DSR comprising;

a single turn transformer (STT) including a winding clamped around the conductor, the STT having a magnetizing inductance and a leakage inductance;

a switching device connected in series with the winding, where the passive inductance is approximately the leakage inductance when the switching device is closed and is approximately the magnetizing inductance when the switching device is open; and

a controller configured to open the switching device when conductor line current reaches a predetermined value.

2. The system in claim 1, wherein the STT further comprises:

two split-core sections;

and

an air-gap separating the two split-core sections, the air-gap configured such that a specified level of magnetizing inductance is produced when the two split-core sections are clamped around the conductor.

3. The system in claim 1, wherein the switching device includes a contact switch that short circuits the winding when the contact switch is in a closed condition.

4. The system in claim 3, wherein the controller is further configured to insert the magnetizing inductance via opening the contact switch.

5. The system in claim 3, wherein the controller is further configured to allow for insertion of the magnetizing inductance via opening the contact switch.

6. The system in claim 3, wherein the contact switch is normally closed.

7. The system in claim 3, wherein the contact switch is an electromechanical switch.

8. The system in claim 1, wherein the controller is further configured to close the switching device when the conductor line current drops below the predetermined value.

9. The system in claim 5, wherein the controller is further configured to remove the magnetizing inductance when the conductor line current drops below the predetermined value via closing the contact switch.

10. The system in claim 5, wherein the switching device further includes a thyristor in parallel with the contact switch that, when open inserts the magnetizing inductance into the conductor and, when closed removes the magnetizing inductance.

11. The system in claim 1, further comprising a plurality of DSRs, wherein each DSR is configured to insert an amount of magnetizing inductance specific to that DSR.

12. The system in claim 2, wherein the STT further comprises a separate winding for each split-core section.

13. The system in claim 12, wherein the STT further comprises a separate contact switch for each separate winding.

14. The system in claim 1, further comprising at least two conductors.

15. The system in claim 14, wherein each of the at least two conductors is associated with at least one DSR.

16. The system in claim 1, wherein the controller is further configured to send and receive communications for reprogramming the controller.

17. The system in claim 1, wherein the controller is further configured to send and receive communications with controllers associated with other DSRs.

18. The system in claim 1, wherein the controller may be reprogrammed via a short range remote control.

19. A system for implementing line overload control via providing distributed series impedance, the system comprising:

at least one distributed series reactors (DSR) configured to insert a passive inductance into a conductor, each DSR comprising;

a split-core clamped around a conductor, the split-core including an air-gap having a distance corresponding to a predefined magnetizing inductance;

means for determining that a conductor line current has reached a predefined value; and

means for changing the amount of passive inductance inserted into the conductor, wherein the passive inductance is approximately the predefined magnetizing inductance when the predefined value is exceeded.

20. The system in claim 19, wherein the means for changing the amount of passive inductance inserted into the conductor changes the air-gap from an initial distance to the distance corresponding to the predefined magnetizing inductance.

21. The system in claim 19, further comprising means for bypassing the DSR by shorting a winding of the DSR.

22. The system in claim 19, further comprising means for deriving power from conductor line current.

23. The system in claim 19, further comprising means for communicating with the means for changing the amount of passive inductance inserted into the conductor.

24. A method for implementing line overload control via inserting series impedance into a conductor, the method comprising:

inserting a passive inductance into the conductor via a distributed series reactor (DSR); and

causing the passive inductance inserted into the conductor to change to approximately a magnetizing inductance of the DSR when conductor line current reaches a predetermined value.

25. The method of claim 24, wherein the DSR comprises a single turn transformer clamped around the conductor wherein an air gap is configured to provide the magnetizing inductance.

26. The method of claim 24, further comprising deriving power for a controller from conductor line current.

27. The method of claim 24, further comprising opening a contact switch to allow the passive inductance to change when conductor line current reaches the predetermined value.

28. The method of claim 27, wherein opening the contact switch causes the passive inductance to change.

29. The method of claim 27, further comprising closing the contact switch when conductor line current drops below the predetermined value.

30. The method of claim 29, wherein closing the contact switch changes the passive inductance to approximately a leakage inductance of the DSR.

31. The method of claim 24, further providing passive inductance via at least two DSRs.

32. The method of claim 31, wherein each of the at least two DSRs is configured to change the passive inductance to a predetermined magnetizing inductance specific to that DSR, the predefined magnetizing inductance defined by an air-gap distance of that DSR.

33. The method of claim 24, further comprising inserting passive inductance into at least two conductors, each of the at least two conductors being associated with at least one corresponding DSR.

34. The method of claim 24, further comprising communicating programming information to a controller of the DSR.

35. The method of claim 24, further comprising communicating from one DSR to another DSR.