Electrical ground isolation and secondary failure reduction detection and isolation

• US 20030184932A1
• Filed: 04/02/2002
• Published: 10/02/2003
• Est. Priority Date: 04/02/2002
• Status: Active Grant

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Worden, Bret Dwayne, McNally, Christopher Wade, Kumar, Ajith K.
• Granted Patent: US 7,035,065 B2
• Time in Patent Office: Days
• US Class Current: 361/42
• CPC Class Codes: H02H 3/16 responsive to fault current to earth, frame or mass with balanced or differential arrangement H02H3/26 ; monitoring earth connection H02H5/105

Abstract

A system for isolating electrical ground faults and secondary failures in an electrical system, the system comprising an AC ground isolation state machine for detecting and isolating an AC ground, a DC ground isolation state machine for detecting and isolating a DC ground, a component failure isolation state machine for detecting and isolating a change in a resistance, and a component failure early detection algorithm for determining a failure before using the state machines.

Claims

1. A method for isolating AC electrical ground faults in an electrical system, said method comprising:

(a) detecting a component causing said AC ground;

(b) verifying said component causing said AC ground is actually causing said ground; and

(c) isolating said component causing said ground.

2. The method of claim 1, further comprising resetting said component to work after a specific period.

3. The method of claim 1 wherein said step of isolating a component further comprises:

(a) disabling a group of components to determine if said AC ground is detected; and

(b) if said AC ground is still detected, disabling an individual component in said group and enabling other components in said group to determine if said AC ground is detected.

4. The method of claim 1 wherein said electrical system is a locomotive electrical system.

43. The method of claim 1 wherein said electrical system is a locomotive electrical system.

5. A method for isolating a DC electrical ground fault in an electrical system, said method comprising:

(a) detecting a DC ground;

(b) isolating a suspected component;

(c) verifying said isolated component is causing said DC ground; and

(d) if said component is not verified as causing said DC ground, considering other sources causing said ground.

6. The method of claim 5 wherein said detecting step further comprises:

(a) determining a number of components in said system;

(b) disabling all but one component leaving one component enabled; and

(c) determining if said ground is in said enabled component.

7. The method of claim 5 wherein said verifying step further comprises applying a low voltage to determine whether said ground is detected when said low voltage is applied.

8. The method of claim 5 wherein said verifying step further comprises applying a high voltage to determine whether said ground is detected when said high voltage is applied.

9. The method of claim 5 wherein said verifying step further comprises enabling other components in said system to confirm said ground is no longer detected.

10. The method of claim 5 wherein said electrical system is a locomotive electrical system.

12. The method of claim 10 wherein said isolation step comprises:

(a) determining a number of components in said system;

(b) disabling all but one component leaving one component enabled; and

(c) determining if said change in resistance is in said enabled component.

13. The system of claim 10 wherein said isolating step further comprises:

(a) applying a low voltage to determine whether said change in resistance is detected when said low voltage is applied.

14. The system of claim 10 wherein said isolating step further comprises:

(a) applying a high voltage to determine whether said change in resistance is detected when said high voltage is applied.

15. The method of claim 10 wherein said verifying step further comprises enabling other components in said system to confirm said change in resistance is no longer detected.

16. The method of claim 10 wherein said electrical system is a locomotive electrical system.

18. The method of claim 15 wherein said comparing step comprises comparing a component'"'"'s expected resistance to said component'"'"'s collected resistance.

19. The method of claim 15 where said comparing step comprises comparing a component'"'"'s expected voltage value to said component'"'"'s collected voltage value.

20. The method of claim 15 wherein said electrical system is a locomotive electrical system.

22. The system of claim 18 wherein any of said first state, second state, third state, fourth state, or fifth state are combined into a single state.

23. The system of claim 18 wherein said second state is a sub state machine comprising:

(a) a first sub state to disable a group of said plurality of components; and

(b) a second sub state to disable an individual component of said plurality of components.

24. The system of claim 20 wherein said first sub state and said second sub state can be combined into a single sub state.

25. The system of claim 20 further comprising a third sub state to inform said system of a component of said plurality of components suspected of causing said ground and wherein said first sub state, said second sub state, or said third state can be combined into a single sub state.

26. The method of claim 18 wherein said electrical system is a locomotive electrical system.

28. The system of claim 23 wherein any of said first state, second state, third state, or fourth state are combined into a single state.

29. The system of claim 23 wherein said second state comprises:

(a) a first sub state to determine a number of said plurality of components in said system; and

(b) a second sub state to allow one component to be enabled while all other components are disabled to determine if said DC ground is in said enabled component.

30. The system of claim 25 wherein said first sub state and said second sub state can be combined into a single sub state.

31. The system of claim 25 further comprising a third sub state to inform said system of a component suspected of causing said ground and wherein said first sub state, said second sub state, or said third state can be combined into a single sub state.

32. The system of claim 25 wherein said second sub state further comprises:

(a) a first test sub state to determine whether said ground is detected when a low voltage is applied to said suspected component; and

(b) a second test sub state to determine whether said ground is detected when a high voltage is applied to said suspected component.

33. The system of claim 23 wherein said third state leaves said grid box causing said ground disabled and enables other grid boxes in said propulsion system to confirm said ground is no longer detected.

34. The system of claim 23 wherein said fourth state comprises a state that compares a chance in resistance of said system.

35. The method of claim 23 wherein said electrical system is a locomotive electrical system.

37. The system of claim 31 wherein any of said first state, second state, third state, or fourth state are combined into a single state.

38. The system of claim 31 wherein said second state comprises:

(a) a first sub state to determine a number of said plurality of components in said system; and

(b) a second sub state to allow one component to be enabled while all other components are disabled to determine if said change in resistance is in said enabled component.

39. The system of claim 25 wherein said first sub state and said second sub state can be combined into a single sub state.

40. The system of claim 33 further comprising a third sub state to inform said system of a component suspected of causing said change in resistance and wherein said first sub state, said second sub state, or said third state can be combined into a single sub state.

41. The system of claim 33 wherein said second sub state further comprises:

(a) a first test sub state to determine whether said change in resistance is detected when a low voltage is applied to said suspected component; and

(b) a second test sub state to determine whether said change in resistance is detected when a high voltage is applied to said suspected component.

42. The system of claim 31 wherein said third state leaves said component causing said change in resistance disabled and enables other components in said system to confirm said ground is no longer detected.

45. The system of claim 38 wherein said processor compares said component'"'"'s expected resistance to said component'"'"'s collected resistance.

46. The method of claim 38 wherein said processor compares said component'"'"'s expected voltage value to said component'"'"'s collected voltage value.

47. The method of claim 38 wherein said electrical system is a locomotive electrical system.

49. The system of claim 41 further comprising a traction motor ground isolation per axle torque limit system connected to said AC ground isolation state machine.

50. The system of claim 41 further comprising a supplemental voltage functions system providing voltage average rates and alternator rectifier bias state information to said state machines and said early detection algorithm.

51. The system of claim 41 wherein said dynamic braking grid failure early detection algorithm comprises a model of operation conditions which are compared to actual operation conditions to determine a failure in said propulsion system.

52. The method of claim 41 wherein said algorithm compares a modeled speed of a blower to an actual speed of said blower.

11. A method for isolating a DC electrical fault in an electrical system, said method comprising:

(a) isolating a suspected component when a change in resistance is detected; and

(b) verifying said isolated component is causing said change in resistance.

17. A method for detecting an early failure in a component in an electrical system, said method comprising:

(a) providing a model of operational conditions;

(b) collecting actual operational conditions; and

(c) comparing said model of operational conditions with said actual operational conditions to determine when said failure occurs.

21. A system for isolating AC electrical ground faults in an electrical system, said system comprising:

(a) a plurality of components;

(b) a first state where said system waits until an AC ground is detected;

(c) a second state to isolate a component causing said AC ground;

(d) a third state to verify component causing said AC ground is actually causing said ground;

(e) a fourth state to isolate said component causing said ground; and

(f) a fifth state to enable said component after a specific period.

27. A system for isolating DC electrical ground faults in an electrical system, said system comprising:

(a) a plurality of components;

(b) a first state where said system waits until a DC ground is detected;

(c) a second state where said systems transitions when a DC ground is detected to isolate a suspected component;

(d) a third state to verify said suspected component isolated is causing said DC ground; and

(e) a fourth state to consider other sources if a suspected component is not identified as causing said DC ground.

36. A system for isolating a change in resistance in an electrical system, said system comprising:

(a) a plurality of components;

(b) a first state where said system waits until a change in resistance is detected;

(c) a second state where said systems transitions when a change in resistance is detected to isolate a suspected component; and

(d) a third state to verify said suspected component isolated is causing said change in resistance.

44. A system for detecting an early failure in a component in an electrical system, said system comprising:

(a) a model of operational conditions specific to said component;

(b) a collection of actual operational conditions from said component; and

(c) a processor to compare said model of operational conditions with said collection of actual operational conditions to determine when said failure occurs.

48. A system for isolating electrical ground faults and secondary failures in a locomotive propulsion system, said system comprising:

(a) an AC ground isolation state machine for isolating a traction motor or alternator when an AC ground is detected;

(b) a DC ground isolation state machine for isolating a grid box when a DC ground is detected;

(c) a dynamic braking grid failure isolation state machine for isolating a grid box when a change in resistance is detected; and

(d) a dynamic braking grid failure early detection algorithm for determining a failure before using said state machines.