System and method for monitoring power in a utility meter

• US 20090261805A1
• Filed: 04/21/2008
• Published: 10/22/2009
• Est. Priority Date: 04/21/2008
• Status: Active Grant

• Current Assignee: Elster Electricity LLC (Honeywell International Inc.)
• Original Assignee: Elster Electricity LLC (Honeywell International Inc.)
• Inventors: Shuey, Kenneth C.
• Granted Patent: US 7,772,829 B2
• Time in Patent Office: Days
• US Class Current: 324/76.110
• CPC Class Codes: G01R 21/133 by using digital technique
• CPC Class Codes: H02H 11/006 in case of too high or too low voltage

Abstract

A power meter for measuring power consumption and detecting the presence of an unsafe line condition is disclosed. The power meter has a service disconnect switch, which is interposed between load contacts and source contacts, the disconnect switch interrupts the flow of power from the source contacts to the load contacts when the disconnect switch is in an open position. The power meter also has a processor coupled to a two input signal processing circuit. The two input signal processing circuit receives a first and second voltage signal from the load contacts. The two input signal processing circuit converts the first and second voltage signal into a first and second voltage value. The processor computes the power consumption using the first and second voltage values in combination with current values. The processor uses the first or second voltage value a to determine the presence of an unsafe line condition when either the first or second voltage value exceeds a first voltage threshold or the first or second voltage value is below a second voltage threshold when the service disconnect switch is in the open position.

Claims

1. A power meter for measuring power consumption and detecting the presence of an unsafe line condition comprising:

a service disconnect switch, the service disconnect switch interposed between load contacts and source contacts, the disconnect switch interrupting a flow of power from the source contacts to the load contacts when the disconnect switch is in an open position;

a processor coupled to;

a two input signal processing circuit, the signal processing circuit receiving a first and second voltage signal from the load contacts, the two input signal processing circuit converting the first and second voltage signals into a first and second voltage values, the processor computing power consumption using the first and second voltage values in combination with current values, the processor further using the first or second voltage values to determine the presence of unsafe line conditions when either of the first or second voltage values exceed a first voltage threshold or are below a second voltage threshold when the service disconnect switch is in the open position.

2. The power meter of claim 1 wherein the processing circuit is a digital signal processor (DSP).

3. The power meter of claim 1 wherein the first voltage threshold is about 170 VAC.

4. The power meter of claim 1 wherein the second voltage threshold is about 50 VAC.

5. The power meter of claim 1 wherein the power meter is a two wire single phase single element power meter.

6. The power meter of claim 1 wherein the two input signal processing circuit is contained within the processor.

7. A method for calculating an amount of power flowing through a power meter and detecting the presence of an unsafe line condition the method comprising:

providing the power meter having a service disconnect switch, the service disconnect switch allowing power to flow from source contacts to load contacts when the service disconnect switch is in a closed position and not allowing power to flow from source contacts to load contacts when the service disconnect switch is in an open position, the power meter further having a two input signal processing circuit, the two input signal processing circuit receiving a first and a second voltage signal from the load contacts;

converting the first and second voltage signal by the two input signal processing circuit into a first and second voltage value;

sending the first and second voltage value to a processor;

calculating the amount of power flowing through the power meter by using the first and second voltage values;

determining if either of the first or second voltage values is greater than a first voltage threshold or if either the first or second voltage values is less than a second voltage threshold when the service disconnect switch is in the open position; and

,

indicating that the unsafe line condition exists if either of the first or second voltage values is greater than the first voltage threshold or if either of the first or second voltage values is less than the second voltage threshold.

8. The method of claim 7 wherein the processing circuit is a digital signal processor (DSP).

9. The method of claim 7 wherein the first voltage threshold is about 170 VAC.

10. The method of claim 7 wherein the second voltage threshold is about 50 VAC.

11. The method of claim 7 wherein the power meter is a two wire single phase single element power meter.

12. A power meter for measuring power consumption and detecting the presence of an unsafe line condition comprising:

a service disconnect switch, the service disconnect switch interposed between load contacts and source contacts, the service disconnect switch interrupting a flow of electricity from the source contacts to the load contacts when the disconnect switch is in an open position;

a processor coupled with

a two input signal processing circuit receiving a first and second voltage signal from the load contacts, the two input signal processing circuit converting the first and second voltage signal into a first and second voltage value, the processor computing power consumption using the first and second voltage value in combination with first and second current values, the first and second voltage values further used by the processor to determine the presence of an unsafe line condition when the first or second voltage value exceeds a first voltage threshold when the service disconnect switch is in the open position.

13. The power meter of claim 12 wherein the power meter is a three wire, two phase, two element power meter.

14. The power meter of claim 12 wherein the first voltage threshold is about 70 VAC.

15. The power meter of claim 12 wherein the two input signal processing circuit is contained within the processor.

16. The power meter of claim 12 wherein the two input signal processing circuit is a digital signal processor (DSP).

17. A power meter for measuring power consumption and detecting the presence of an abnormal line condition comprising:

a service disconnect switch, the service disconnect switch interposed between a load contact and a source contact, the disconnect switch interrupting a flow of power from the source contact to the load contact when the disconnect switch is in an open position;

a processor coupled to;

a two input signal processing circuit, the two input signal processing circuit receiving a load voltage signal from the load contact and a source voltage signal from the source contact, the two input signal processing circuit converting the load and source voltage signals into a load and source voltage values, the processor computing power consumption using the load voltage values in combination with a current value, the processor further using the source voltage value to determine the presence of an abnormal line condition when the load voltage value differs from the source voltage value.

18. The power meter of claim 17 wherein the power meter is a two wire, single phase, single element power meter.

19. The power meter of claim 17 wherein the first voltage threshold is about 70 VAC.

20. The power meter of claim 17 wherein the two input signal processing circuit is contained within the processor.

21. The power meter of claim 17 wherein the two input signal processing circuit is a digital signal processor (DSP).