METHOD, DEVICE, AND SYSTEM FOR MONITORING CURRENT PROVIDED TO A LOAD

• US 20130271886A1
• Filed: 04/13/2012
• Published: 10/17/2013
• Est. Priority Date: 04/13/2012
• Status: Active Grant

• Current Assignee: ABB SPA (ABB Limited)
• Original Assignee: General Electric Company
• Inventors: Cull, Zachary Herman, Williams, Craig Benjamin
• Granted Patent: US 9,030,793 B2
• Time in Patent Office: Days
• US Class Current: 361/87
• CPC Class Codes: H02H 1/06 Arrangements for supplying operative power power supply arrangements in general G05F, H02M
• CPC Class Codes: H02H 3/08 responsive to excess current responsive to abnormal temperature caused by excess current H02H5/04

Abstract

A circuit protection device for monitoring a current flowing from an electrical distribution line through a trip mechanism to a load includes an input conductor configured to receive a current signal from a sensor. At least one resistor is arranged to receive the current signal from the input conductor, and provides a voltage signal proportional to the current signal. The circuit protection device includes a control circuit coupled in parallel with the resistor and a power supply that receives the current signal from the resistor and supplies power to the control circuit based on the current signal. The control circuit is configured to receive the voltage signal and determine an amplitude of the current flowing through the trip mechanism based on the voltage signal. The control circuit is also configured to determine whether a predetermined current threshold is exceeded and to generate a control signal to activate the trip mechanism.

Claims

1. A circuit protection device for use in monitoring a current flowing from an electrical distribution line through a trip mechanism to a load, said circuit protection device comprising:

an input conductor configured to receive a current signal from a sensor;

at least one resistor coupled to said input conductor, said at least one resistor arranged to receive the current signal and configured to provide a voltage signal proportional to the current signal;

a control circuit coupled in parallel with said at least one resistor and configured to;

receive the voltage signal;

determine an amplitude of the current flowing through the trip mechanism based on the voltage signal;

determine whether a predetermined current threshold is exceeded; and

generate a control signal to activate the trip mechanism; and

a power supply coupled to said at least one resistor and configured to;

receive the current signal from said at least one resistor; and

supply power to said control circuit based on the current signal.

2. A circuit protection device in accordance with claim 1, wherein said control circuit is configured to generate the control signal when the amplitude of the current flowing through the trip mechanism exceeds the predetermined current threshold.

3. A circuit protection device in accordance with claim 1, wherein the current signal is an alternating current (AC) signal, wherein said power supply is configured to convert the current signal to direct current (DC) and supply DC power to said control circuit using the converted current signal.

4. A circuit protection device in accordance with claim 1, wherein the current signal is an alternating current (AC) signal, said at least one resistor provides an AC signal to said control circuit as the voltage signal.

5. A circuit protection device in accordance with claim 4, wherein said control circuit comprises an analog to digital converter (ADC) configured to convert the voltage signal into data for use in determining the amplitude of the current flowing through the trip mechanism.

6. A circuit protection device in accordance with claim 5, wherein said control circuit comprises a gain circuit coupled to said ADC and configured to adjust an amplitude of the voltage signal for use with said ADC.

7. A circuit protection device in accordance with claim 5, wherein said control circuit comprises a processor coupled to said ADC, wherein said processor receives the data and uses the data to determine the amplitude of the current flowing through the trip mechanism.

8. A circuit protection system for use in monitoring current provided to a load from an electrical distribution line, said circuit protection system comprising:

a trip mechanism configured to be coupled the electrical distribution line and to the load to enable a current received from the electrical distribution line to flow through said trip mechanism to the load, said trip mechanism further configured to be activated to interrupt the current flowing to the load;

a sensor configured to measure the current flowing through said trip mechanism and to generate a current signal representative of the measured current; and

a circuit protection device coupled to said sensor and comprising;

an input conductor configured to receive the current signal from said sensor;

at least one resistor coupled to said input conductor, said at least one resistor arranged to receive the current signal and configured to provide a voltage signal proportional to the current signal;

a control circuit coupled in parallel with said at least one resistor and configured to;

receive the voltage signal;

determine an amplitude of the current flowing through said trip mechanism to the load based on the voltage signal;

determine whether a predetermined current threshold is exceeded; and

generate a control signal to activate said trip mechanism; and

a power supply coupled to said at least one resistor and configured to;

receive the current signal from said at least one resistor; and

supply power to said control circuit based on the current signal.

9. A circuit protection system in accordance with claim 8, wherein said control circuit is configured to generate the control signal when the amplitude of the current flowing through said trip mechanism exceeds the predetermined current threshold.

10. A circuit protection system in accordance with claim 8, wherein the current signal is an alternating current (AC) signal, wherein said power supply is configured to convert the current signal to direct current (DC) and supply DC power to said control circuit using the converted current signal.

11. A circuit protection system in accordance with claim 10, wherein the current signal is an alternating current (AC) signal, said at least one resistor provides an AC signal to said control circuit as the voltage signal.

12. A circuit protection system in accordance with claim 11, wherein said control circuit comprises an analog to digital converter (ADC) configured to convert the voltage signal into data for use in determining the amplitude of the current flowing through said trip mechanism.

13. A circuit protection system in accordance with claim 12, wherein said control circuit comprises a gain circuit coupled to said ADC and configured to adjust an amplitude of the voltage signal for use with said ADC.

14. A circuit protection system in accordance with claim 12, wherein said control circuit comprises a processor coupled to said ADC, wherein said processor receives the data and uses the data to determine the amplitude of the current flowing through said trip mechanism.

15. A circuit protection system in accordance with claim 8, further comprising a flux shifter coupled to said control circuit, wherein said flux shifter is configured to receive the control signal and activate said trip mechanism in response to the control signal.

16. A method of monitoring current provided to a load using a circuit protection device, said method comprising:

receiving a current signal representative of an amount of current flowing through a trip mechanism to the load;

transmitting the current signal through at least one resistor to provide a voltage signal proportional to the current signal;

determining an amplitude of the current flowing through the trip mechanism to the load based on the voltage signal;

determining whether a predetermined current threshold is exceeded; and

generating a control signal to activate the trip mechanism to prevent current from being provided to the load.

17. A method in accordance with claim 16, wherein the current signal is an alternating current (AC) signal, said method further comprising:

receiving the current signal from the at least one resistor;

converting the current signal to direct current (DC); and

supplying DC power to at least one component of the circuit protection device using the converted current signal.

18. A method in accordance with claim 16, further comprising generating a magnetic field in response to the control signal, wherein the magnetic field causes the trip mechanism to be activated.

19. A method in accordance with claim 16, further comprising conditioning the voltage signal before said determining an amplitude of the current flowing through the trip mechanism.

20. A method in accordance with claim 16, further comprising generating the control signal when the amplitude of the current flowing through the trip mechanism exceeds the predetermined current threshold.