Systems, methods, and devices for controlling a serial arc fault in an electrical circuit

• US 7,872,839 B2
• Filed: 05/12/2009
• Issued: 01/18/2011
• Est. Priority Date: 05/12/2009
• Status: Active Grant

• Current Assignee: Astronics Advanced Electronic Systems Corporation (Astronics Corporation)
• Original Assignee: Astronics Advanced Electronic Systems Corporation (Astronics Corporation)
• Inventors: Potter, Frederick J., Wright, James Arnold
• Primary Examiner(s): Nguyen; Danny
• Application Number:
  US12/464,373
• Publication Number:
  US 20100290162A1
• Time in Patent Office: 616 Days
• Field of Search: 361 42- 50
• US Class Current: 361/42
• CPC Class Codes: H02H 1/0015 Using arc detectors
• CPC Class Codes: H02H 1/04 Arrangements for preventing response to transient abnormal conditions, e.g. to lightning or to short duration over voltage or oscillations; Damping the influence of dc component by short circuits in ac networks

Abstract

Methods, systems, and devices for controlling a serial arc fault in an electrical circuit are disclosed. In some embodiments, the methods include the following: a. measuring a current in the circuit; b. determining whether the current is below a predetermined value; c. if the current is below ten percent of the predetermined value, determining whether a countdown timer value indicated by a cell pointer value is equal to zero; d. if the countdown timer value is equal to zero, starting a countdown timer, advancing the cell pointer value by one, and restarting the method at step a.; e. if the countdown timer value is not equal to zero, determining whether the interruptions in the current are periodic; f. if the interruptions in the current are not periodic, checking whether an arc event countdown timer is running; and g. if the arc event countdown timer is running, tripping a circuit breaker.

Claims

1. A method of controlling a serial arc fault in an electrical circuit, said method comprising:

a. measuring a current running through said electrical circuit;

b. determining whether said current is below a predetermined average current for said electrical circuit by a predetermined amount;

c. if said current is below ten percent of said predetermined average current for said electrical circuit, noting an interruption in said current and determining whether a countdown timer value in a data cell indicated by a cell pointer value is equal to zero;

d. if said countdown timer value is equal to zero, starting a countdown timer in said data cell, advancing said cell pointer value by one, and restarting said method at step a.;

e. if said countdown timer value is not equal to zero, determining whether said interruptions in said current are periodic;

f. if said interruptions in said current are not periodic, noting occurrence of an arc event in said electrical circuit and checking whether an arc event countdown timer is running; and

g. if said arc event countdown timer is running, noting occurrence of a serial arc fault in said electrical circuit and tripping a circuit breaker of said electrical circuit.

2. A method according to claim 1, wherein said predetermined amount is about ten percent of said predetermined average current.

3. A method according to claim 1, wherein if said current is greater than ten percent of said predetermined average current, said method is restarted at step a.

4. A method according to claim 1, wherein said countdown timer has a beginning value of 1000 units, each of said units being equal to 100 μ

s.

5. A method according to claim 1, wherein if a countdown timer value in a first data cell reaches zero before a predetermined number of data cells are populated with countdown value timers, all the countdown timer values in all the data cells are reset to zero, said cell pointer value is reset to a first position at said first data cell, and said method is restarted at step a.

6. A method according to claim 5, wherein said predetermined number of data cells is about ten.

7. A method according to claim 1, wherein determining whether said interruptions in said current are periodic comprises:

determining a difference between said countdown timer values of the last two of said predetermined number of data cells started;

calculating a threshold value by multiplying said difference by a predetermined value; and

determining differences between adjacent ones of said countdown timer values of the remaining of said predetermined number of data cells started;

wherein said interruptions are not periodic if said differences are greater than said threshold value.

8. A method according to claim 1, wherein if said interruptions are periodic, all countdown timer values are reset to zero, said cell pointer value is reset to a first position at said first cell, and said method is restarted at step a.

9. A method according to claim 1, wherein if said current is greater than zero, a warm-up countdown timer is started.

10. A method according to claim 9, wherein when said warm-up countdown timer is started, a cool down countdown timer is reset.

11. A method according to claim 10, wherein when said circuit breaker is tripped, said cool down countdown timer is started and said warm-up timer is reset.

12. A method according to claim 1, wherein if said arc event countdown timer is not running, said arc event countdown timer having a predetermined beginning value is started.

13. A method according to claim 12, wherein said predetermined beginning value is two seconds.

14. A method according to claim 12, further comprising:

after starting said arc event countdown timer, restarting said method at step a.

15. A system for controlling a serial arc fault in an electrical circuit, said system comprising:

a measurement module for measuring a current running through said electrical circuit, said measurement module being in electrical communication with said electrical circuit;

a control module including a processor and computer readable medium, said processor being configured to execute instructions contained on said computer readable medium, said instructions including

a. determining whether said current measured in said measurement module is below a predetermined average current for said electrical circuit by a predetermined amount;

b. if said current is below ten percent of said predetermined average current for said electrical circuit, noting an interruption in said current and determining whether a countdown timer value in a data cell indicated by a cell pointer value is equal to zero;

c. if said countdown timer value is equal to zero, starting a countdown timer in said data cell, advancing said cell pointer value by one, and measuring said current in said electrical circuit using said measurement module;

d. if said countdown timer value is not equal to zero, determining whether said interruptions in said current are periodic;

e. if said interruptions in said current are not periodic, noting occurrence of an arc event in said electrical circuit and checking whether an arc event countdown timer is running; and

f. if said arc event countdown timer is running, noting occurrence of a serial arc fault in said electrical circuit; and

a circuit breaker module for tripping a circuit breaker of said electrical circuit upon noting an occurrence of a serial arc fault in said electrical circuit by said control module, said circuit breaker module being configured to adjustably control a flow of said current to said electrical circuit.

16. A system according to claim 15, wherein said predetermined amount is about ten percent of said predetermined average current.

17. A system according to claim 15, wherein said countdown timer has a beginning value of 1000 units, each of said units being equal to 100 μ

s.

18. A device for detecting a serial arc fault in an electrical circuit, said device comprising:

a housing;

a measurement lead extending from an end of said housing, said measurement lead being used for measuring a current running through said electrical circuit, said measurement lead adapted to be removably in electrical communication with said electrical circuit;

a processor and computer readable medium positioned within said housing and in communication with said measurement lead, said processor being configured to execute instructions contained on said computer readable medium, said instructions including

a. determining whether said current measured by said measurement lead is below a predetermined average current for said electrical circuit by a predetermined amount;

b. if said current is below ten percent of said predetermined average current for said electrical circuit, noting an interruption in said current and determining whether a countdown timer value in a data cell indicated by a cell pointer value is equal to zero;

c. if said countdown timer value is equal to zero, starting a countdown timer in said data cell, advancing said cell pointer value by one, and measuring said current in said electrical circuit using said measurement module;

d. if said countdown timer value is not equal to zero, determining whether said interruptions in said current are periodic;

e. if said interruptions in said current are not periodic, noting occurrence of an arc event in said electrical circuit and checking whether an arc event countdown timer is running; and

f. if said arc event countdown timer is running, noting occurrence of a serial arc fault in said electrical circuit; and

a circuit breaker activator in communication with said processor and a circuit breaker for said electrical circuit, wherein said circuit breaker activator trips said circuit breaker of said electrical circuit upon occurrence of a serial arc fault in said electrical circuit as indicated by said processor.

19. A system according to claim 18, wherein said predetermined amount is about ten percent of said predetermined average current.

20. A system according to claim 18, wherein said countdown timer has a beginning value of 1000 units, each of said units being equal to 100 μ

s.