11-BUSBAR_PROTECTION_BUSBAR_PROTECTION_RF.pdf
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This document discusses busbar protection methods for electrical substations. It describes the drawbacks of not having busbar protection such as slow fault clearance times, and the benefits of busbar protection like fast fault clearance. Several methods of providing busbar protection are described, including frame leakage protection, blocking scheme protection, and high impedance differential protection. Requirements for reliable, stable, discriminating and fast operation of busbar protection systems are also outlined.
11-BUSBAR_PROTECTION_BUSBAR_PROTECTION_RF.pdf
- 1. 08/02 05/02/03 1 1 05/02/03 1 Busbar Protection Protection & Contr担le / Application Rev. A JM, September 2004
- 2. 08/02 05/02/03 2 2 Without Busbar Protection F2 F1 z There are fewer faults on busbars than on other parts of the power system. z No risk of dislocation of system due to accidental operation of busbar protection. Argues
- 3. 08/02 05/02/03 3 3 Without Busbar Protection F2 F1 z Slow fault clearance. Busbar faults at F1 and F2 are cleared by remote time delayed protection on circuits feeding the faults: Time Delayed Overcurrent or Time Delayed Distance Protection Drawbacks
- 4. 08/02 05/02/03 4 4 With Busbar Protection BUSBAR ZONE F1 z Fast clearance by breakers at the busbars
- 5. 08/02 05/02/03 5 5 With Busbar Protection BUSBAR ZONE F2 F1 z Where busbars are sectionalised, Protection can limit the amount of system disruption for a busbar fault
- 6. 08/02 05/02/03 6 6 With Busbar Protection 21 21 87BB 87BB 1/2 SS 1 SS 2 SS 3
- 7. 08/02 05/02/03 7 7 With Busbar Protection 21 21 87BB 87BB 2/2
- 8. 08/02 05/02/03 8 8 With No Busbar Protection 21 21 21 21 21 1/2
- 9. 08/02 05/02/03 9 9 With No Busbar Protection 21 21 2/2 21 21 21
- 10. 08/02 05/02/03 10 10 With Burbar protection 21 21 21 21 21 21 21 87BB 87BB With No Burbar protection
- 11. 08/02 05/02/03 11 11 Busbar Faults Are Usually Permanent Causes of Busbar Faults : z Falling debris z Insulation failures z Circuit breaker failures z Current transformer failures z Isolators switchs operated on load or outside their ratings z Safety earths left connected Therefore : Circuit breakers should be tripped and locked out by busbar protection
- 12. 08/02 05/02/03 12 12 Busbar Protection must be : z RELIABLE Failure to trip could cause widespread damage to the substation z STABLE False tripping can cause widespread interruption of supplies to customers / possible power system instability z DISCRIMINATING Should trip the minimum number of breakers to clear the fault z FAST To limit damage and possible power system instability
- 13. 08/02 05/02/03 13 13 Methods of Providing Busbar Protection z Frame to Earth (Leakage) Protection z Blocking Scheme Protection z Differential Protection : High Impedance Low Impedance Insulation >I >I >I >I >I >I
- 14. 08/02 05/02/03 14 14 05/02/03 14 Frame Leakage Protection Protection & Contr担le / Application Rev. A JM, September 2004
- 15. 08/02 05/02/03 15 15 Frame Leakage Busbar Protection Insulation >I
- 16. 08/02 05/02/03 16 16 Frame Leakage Busbar Protection >I
- 17. 08/02 05/02/03 17 17 Frame Leakage Busbar Protection >I
- 18. 08/02 05/02/03 18 18 Frame Leakage Busbar Protection >I >I
- 19. 08/02 05/02/03 19 19 Frame Leakage Busbar Protection z Can detect only earth faults z Switchgear must be insulated from earth (by standing on concrete plinth) z Only one single earth conductor allowed on switchgear z All cable glands must be insulated z Switchgear sections must be insulated
- 20. 08/02 05/02/03 20 20 Frame Leakage Busbar Protection Neutral Check >I >I False Operation because induced loop No operation prevents from false trip
- 21. 08/02 05/02/03 21 21 Frame Leakage Busbar Protection Neutral Check >I >I
- 22. 08/02 05/02/03 22 22 Neutral Check Frame Leakage Busbar Protection >I >I
- 23. 08/02 05/02/03 23 23 05/02/03 23 Blocking Scheme Protection Protection & Contr担le / Application Rev. A JM, September 2004
- 24. 08/02 05/02/03 24 24 >I >I >I >I >I Blocking Scheme Busbar Protection
- 25. 08/02 05/02/03 25 25 >I >I >I >I >I Blocking Scheme Busbar Protection
- 26. 08/02 05/02/03 26 26 >I >I >I >I >I Blocking Scheme Busbar Protection
- 27. 08/02 05/02/03 27 27 05/02/03 27 High Impedance Protection Protection & Contr担le / Application Rev. A JM, September 2004
- 28. 08/02 05/02/03 28 28 08/02 05/02/03 28 Single Bus Substation
- 29. 08/02 05/02/03 29 29 Single Bus Substation P1 P2 S1 S2 P1 P2 S1 S2 P1 P2 S1 S2
- 30. 08/02 05/02/03 30 30 Single Bus Substation
- 31. 08/02 05/02/03 31 31 Single Bus Substation
- 32. 08/02 05/02/03 32 32 Single Bus Substation
- 33. 08/02 05/02/03 33 33 08/02 05/02/03 33 Double Bus Substation
- 34. 08/02 05/02/03 34 34 Isolator Auxiliary Switches Current switching Bus A Bus B a b Current P1 P2 S1 S2 P1 P2 S1 S2 P1 P2 S1 S2 P1 P2 S1 S2 P1 P2 S1 S2
- 35. 08/02 05/02/03 35 35 Isolator Auxiliary Switches Current switching Bus A Bus B a b Current
- 36. 08/02 05/02/03 36 36 Isolator Auxiliary Switches Current switching Bus A Bus B a b Current
- 37. 08/02 05/02/03 37 37 Isolator Auxiliary Switches Current switching Bus A Bus B a b Current
- 38. 08/02 05/02/03 38 38 Isolator Auxiliary Switches Current switching Bus A Bus B a b Current
- 39. 08/02 05/02/03 39 39 Isolator Auxiliary Switches Current switching Bus A Bus B a b Current
- 40. 08/02 05/02/03 40 40 Isolator Auxiliary Switches Tripping switching Bus A Current Bus B a b Tripping a b
- 41. 08/02 05/02/03 41 41 Interposing CT are not acceptable z Main CT must be identical z Current switching via auxilliary relay is not acceptable. Requirement of number of position contact (Disconnector switch) is high
- 42. 08/02 05/02/03 42 42 Isolator Auxiliary Switches Current switching Bus A Bus B a b Current
- 43. 08/02 05/02/03 43 43 Isolator Auxiliary Switches Current switching Bus A Bus B a b Bus A Bus B a b Current Current
- 44. 08/02 05/02/03 44 44 Isolator Auxiliary Switches On Load Transfer Bus A Bus B a b Current
- 45. 08/02 05/02/03 45 45 Isolator Auxiliary Switches On Load Transfer Bus A Bus B a b Current
- 46. 08/02 05/02/03 46 46 Isolator Auxiliary Switches On Load Transfer Bus A a b Bus B Current
- 47. 08/02 05/02/03 47 47 Isolator Auxiliary Switches On Load Transfer Bus A Bus B a b Current
- 48. 08/02 05/02/03 48 48 Isolator Auxiliary Switches On Load Transfer Bus A Bus B a b Current
- 49. 08/02 05/02/03 49 49 Isolator Auxiliary Switches On Load Transfer Bus A Bus B a b Current
- 50. 08/02 05/02/03 50 50 Isolator Auxiliary Switches On Load Transfer Bus A Bus B a b Current
- 51. 08/02 05/02/03 51 51 Isolator Auxiliary Switches Check Zone Bus A Bus B Trip Bus A Trip Bus B Zone A Zone B
- 52. 08/02 05/02/03 52 52 Isolator Auxiliary Switches Check Zone Bus A Bus B Trip Bus A Trip Bus B Zone A Zone B Current switching failure False Tripping
- 53. 08/02 05/02/03 53 53 Isolator Auxiliary Switches Check Zone Bus A Bus B Trip Bus A Trip Bus B Check Zone Zone A Zone B
- 54. 08/02 05/02/03 54 54 Isolator Auxiliary Switches Check Zone Bus A Bus B Trip Bus A Trip Bus B Zone A Zone B
- 55. 08/02 05/02/03 55 55 Isolator Auxiliary Switches Check Zone Bus A Bus B Trip Bus A Trip Bus B Check Zone
- 56. 08/02 05/02/03 56 56 08/02 05/02/03 56 One Breaker and a Half Substation
- 57. 08/02 05/02/03 57 57 Bus A Bus B P1 P2 S1 S2 P1 S1 P2 S2 P1 P2 S1 S2
- 58. 08/02 05/02/03 58 58 Bus A Bus B
- 59. 08/02 05/02/03 59 59 Bus A Bus B
- 60. 08/02 05/02/03 60 60 Bus A Bus B
- 61. 08/02 05/02/03 61 61 Bus A Bus B
- 62. 08/02 05/02/03 62 62 Bus A Bus B
- 63. 08/02 05/02/03 63 63 Bus A Bus B P1 S1 P2 S2 P1 S1 P2 S2 P1 S1 P2 S2 P1 S1 P2 S2