Method of detecting run-dry conditions in fuel systems

• US 20050195545A1
• Filed: 02/01/2005
• Published: 09/08/2005
• Est. Priority Date: 06/13/2003
• Status: Active Grant

• Current Assignee: TDG Aerospace, Inc.
• Original Assignee: TDG Aerospace, Inc.
• Inventors: Fish, Daniel E., Wagner, Andrew, Evans, David L., Bench, Gerald, Mladenik, John E., Barba, Jose M.
• Granted Patent: US 7,352,550 B2
• Time in Patent Office: Days
• US Class Current: 361/93.1
• CPC Class Codes: H02H 3/00 Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems H02H7/00; systems for change-over to standby supply H02J9/00 ; integrated protection for motors H02H7/0822

Abstract

Systems, methods, and apparatus for fault detection and interruption in power lines are provided. Circuitry is implemented via software and hardware that is configured to sense an operational aspect of a power line, such as current levels in a three-phase power line, and apply signal processing to the sensed operational aspect to detect faults including different types of faults such as transient and steady state faults and can also be configured to identify the type of fault. Information on the fault and the identification of the type of fault can be displayed, stored, or some other output operation can be implemented. Circuitry can be implemented to provide digital signal processing and analog signal processing to, for example, independently and in parallel (e.g., redundant operation) detect faults and respond to faults as they occur (i.e., in real time).

Claims

1. A method for detecting a fault comprising the steps of:

monitoring one or more phase currents in a power line;

detecting a transient in the monitored phase current;

analyzing phase current data to determine the existence of a fault; and

interrupting power to the power line.

2. The method of claim 1, further comprising:

evaluating steady state statistics for faults.

3. The method of claim 1, further comprising:

storing phase current data in a memory.

4. The method of claim 1, further comprising:

determining a threshold phase current; and

comparing the measured phase current to the threshold phase current.

5. The method of claim 1, further comprising:

characterizing the fault as steady state or transient.

6. The method of claim 1, further comprising:

storing steady state phase current data.

7. The method of claim 6, further comprising:

comparing phase current data to the stored steady state phase current data to determine a fault.

8. The method of claim 6, wherein storing steady state phase current data comprises storing phase current data for three phases of a three phase power line.

9. The method of claim 8, further comprising comparing phase current data for three phases of a power line to the stored steady state phase current data for each phase.

10. The method of claim 1, wherein monitoring one or more phase currents comprises monitoring phase currents in a three-phase power line.

11. A method for detecting a fault in a power line fault response device comprising:

sensor circuitry configured for sensing an operational aspect of a power line;

analog signal processing circuitry configured to detect electrical current in the power line and configured to perform an output operation in response to detecting a fault comprising a variation in the detected electrical current; and

digital signal processing circuitry comprising a processor and memory that is configured to detect electrical current in the power line based on the operational aspect and to perform the output operation in response to detecting a variation in the detected electrical current, the steps comprising;

monitoring one or more phase currents in a power line;

detecting a transient in the monitored phase current;

analyzing phase current data to determine the existence of a fault; and

performing an output operation.

12. The method of claim 11, wherein the output operation comprises generating a signaling output.

13. The method of claim 12, wherein the output operation comprises generating the signaling output to signal that the power line should be disconnected from a load to which the power line is supplying power.

14. The method of claim 11, wherein the output operation comprises disconnecting power to the load.

15. The method of claim 11, further comprising filtering transient faults that are detected to eliminate nuisance conditions.

16. The method of claim 15, wherein the filtering further comprises identifying repeated faults in a limited period of time to identify major faults.

17. The method of claim 15, further comprising opening a power relay or switch in response to the detection of a qualified fault

18. The method of claim 17, further comprising generating a signaling output.

19. The method of claim 11, further comprising updating phase current data.

20. The method of claim 11, further comprising releasing the fault condition.