Electric fuse current sensing systems and monitoring methods

Patent metadata

Field	Value
Publication number	US-10180447-B2
Application number	US-201514931046-A
Country	US
Kind code	B2
Filing date	Nov 3, 2015
Priority date	Jul 20, 2015
Publication date	Jan 15, 2019
Grant date	Jan 15, 2019

Abstract

Electrical current sensing and monitoring methods include connecting sensing a voltage across a conductor having a non-linear resistance such as a fuse element. The current flowing in the conductor is calculated based on at least a first detected state of the sensed voltage and a thermal equilibrium characterization of the conductor.

First claim

What is claimed is:

1. An electrical current sensing system comprising:
a conductor having a non-linear resistance when connected to an electrical power system; and
a processor receiving a voltage sensed across the conductor when connected to the electrical power system, the processor being operable to iteratively calculate a current flowing through the conductor based on at least a first detected state of the sensed voltage and a thermal equilibrium characterization of the conductor.

2. The electrical current sensing system of claim 1 , wherein the conductor is a fuse element.

3. The electrical current sensing system of claim 2 , wherein the fuse element is contained in a fuse housing, and the processor is also contained in the fuse housing.

4. The electrical current sensing system of claim 2 , further comprising a fuse holder, and the processor provided on the fuse holder.

5. The electrical current sensing system of claim 2 , further comprising a disconnect switch, and the processor provided on the disconnect switch.

6. The electrical current sensing system of claim 1 , further comprising a reader device configured to communicate with the processor.

7. The electrical current sensing system of claim 6 , further comprising a label associated with the conductor, the reader device configured to read the label and utilize information from the label to calculate the current flowing through the conductor.

8. The electrical current sensing system of claim 1 , wherein the processor is further operable to calculate the current flowing through the conductor based on at least a second detected state of the sensed voltage and a non-thermal equilibrium characterization of the conductor.

9. The electrical current sensing system of claim 8 , wherein the processor is configured to compare a rate of change of the detected state of the sensed voltage and a predetermined ramp rate threshold.

10. The electrical current sensing system of claim 9 , wherein if the rate of change of the detected state of the sensed voltage is below the predetermined ramp rate threshold, the processor is operable to calculate the current flowing through the conductor based on an inverse exponential relationship of resistance and time.

11. The electrical current sensing system of claim 9 , wherein if the rate of change of the detected state of the sensed voltage is above the predetermined ramp rate threshold, the processor is operable to calculate the current flowing through the conductor based on a last prior calculated resistance of the conductor.

12. An electrical current sensing system comprising:
an electrical fuse including a housing, first and second terminal elements, and a fuse element having a non-linear resistance when connected to an electrical power system; and
a processor receiving a voltage sensed across the fuse element when connected to the electrical power system, wherein the processor is operable to iteratively calculate a current flowing through the fuse element in a different manner depending on at least one of a first detected state and second detected state of the voltage sensed across the fuse element;
wherein in the first detected state of the voltage sensed across the fuse element the current is calculated based on the voltage sensed across the fuse element and a thermal equilibrium characterization of the fuse element; and
wherein in the second detected state of the voltage sensed across the fuse element the current is calculated based on the voltage sensed across the fuse element and a non-thermal equilibrium characterization of the fuse element.

13. The electrical current sensing system of claim 12 , wherein the processor is contained in the fuse housing.

14. The electrical current sensing system of claim 12 , further comprising a fuse holder, and the processor provided on the fuse holder.

15. The electrical current sensing system of claim 12 , further comprising a disconnect switch, and the processor provided on the disconnect switch.

16. The electrical current sensing system of claim 12 , the electrical fuse including at least one of a bar code and an RFID tag, the system further comprising a reader device configured to communicate with the at least one of the bar code and the RFID tag to obtain information to make the current calculation.

17. The electrical current sensing system of claim 16 , further comprising a label associated with the electrical fuse, the reader device configured to read the label and utilize information from the label to determine the applicable thermal equilibrium characterization and non-thermal equilibrium characterization.

18. A method of sensing current in a conductor having a non-linear resistance in an electrical power system, the method implemented with a processor-based device, and the method comprising:
sensing a voltage across the conductor when connected to the electrical power system; and
iteratively calculating, by the processor-based device, the current flowing through the conductor based on at least a first detected state of the sensed voltage and a thermal equilibrium characterization of the conductor.

19. The method of claim 18 , wherein sensing a voltage across the conductor when connected to the electrical power system comprises sensing a voltage across a fuse element in an electrical fuse.

20. The method of claim 19 , wherein the electrical fuse includes a fuse housing, and wherein sensing a voltage across the fuse element comprises sensing the voltage at a location inside the fuse housing.

Assignees

• Eaton Intelligent Power Ltd

Inventors

• Kothekar Milind Suresh
• Sharma Santosh Kumar
• Douglass Robert Stephen

Classifications

• H01H2085/0266

  Structural association with a measurement device, e.g. a shunt · CPC title

• G01R31/74

  Testing of fuses · CPC title

• G11C29/027

  in fuses · CPC title

• G11C17/18

  Auxiliary circuits, e.g. for writing into memory · CPC title

• H02H3/046

  Signalling the blowing of a fuse (detecting non functioning of a lamp H05B47/20) · CPC title