Whole structure contactless power consumption sensing

• US 8,930,152 B2
• Filed: 09/25/2009
• Issued: 01/06/2015
• Est. Priority Date: 09/25/2009
• Status: Active Grant

• Current Assignee: University of Washington
• Original Assignee: University of Washington
• Inventors: Patel, Shwetak, Reynolds, Matthew S.
• Primary Examiner(s): Breene, John
• Assistant Examiner(s): HWANG, TIMOTHY
• Application Number:
  US12/567,561
• Publication Number:
  US 20110074382A1
• Time in Patent Office: 1,929 Days
• Field of Search: 702/62
• US Class Current: 702/62
• CPC Class Codes: G01R 15/207 Constructional details independent of the type of device used
• CPC Class Codes: G01R 21/001 Measuring real or reactive component; Measuring apparent energy G01R21/01, G01R21/02, G01R21/08, G01R21/10 and G01R21/127 take precedence
• CPC Class Codes: G01R 21/06 by measuring current and voltage G01R21/08 - G01R21/133 take precedence
• CPC Class Codes: G01R 22/063 related to remote communication
• CPC Class Codes: G01R 35/005 Calibrating; Standards or reference devices, e.g. voltage or resistance standards, "golden" references G01R33/0035, G01R35/002 take precedence

Abstract

A contactless current and power consumption sensor can be safely mounted on a circuit breaker box of a structure, so as to sense the current flow and/or power consumed in the structure. Because the sensor can be mounted on a surface of the circuit breaker box without the need to access energized conductors inside the box, an unskilled person can readily install the sensor to monitor total instantaneous current flow and thus, determine the power consumed by energized devices in the structure on a continuing basis. The output from the sensor can be supplied to a readout or can be conveyed by a wired or wireless link to a computing device disposed at a remote location, where the data can be stored or viewed on a display. By integrating the power consumed over time, the energy usage by the energized devices in a structure can also be determined.

Claims

1. A method for sensing electrical power being provided to a structure, the structure comprises (a) two or more branch circuit breakers, (b) two or more branch electrical power lines that supply at least a portion of the electrical power to a first load in the structure, (c) one or more main electrical power lines that supply the electrical power to the two or more branch electrical power lines and receive the electrical power from a power source external to the structure, the two or more branch electrical power lines are electrically coupled to the one or more main electrical power lines at the two or more branch circuit breakers, and (d) a panel located over at least part of the one or more main electrical power lines and at least part of the two or more branch electrical power lines, the first load comprises a total load of all of two or more electrical devices in the structure that are electrically coupled to the two or more branch electrical power lines, the method comprising:

calibrating an array of current sensors by detecting a change in a magnitude of an electrical current in the one or more main electrical power lines after at least one known load of the two or more electrical devices has been electrically coupled to the one or more main electrical power lines, wherein calibrating the array of current sensors comprises accounting for non-linearities in magnetic fields at the panel, calibrating the array of current sensors comprises;

determining a calibration factor using the change in the magnitude of the electrical current in the one or more main electrical power lines;

using the array of current sensors to sense the electrical current flowing in the one or more main electrical power lines;

producing an output signal indicative of the electrical current in the one or more main electrical power lines;

processing the output signal to determine the electrical current flowing in the one or more main electrical power lines, wherein processing the output signal comprises using the calibration factor;

sensing a voltage on at least one of the one or more main electrical power lines; and

computing the electrical power being provided to the structure using the voltage and the electrical current flowing in the one or more main electrical power lines,

wherein;

the array of current sensors is affixed at a region of a surface of the panel that is located over or near the at least the part of the one or more main electrical power lines wherein the array of current sensors is devoid of being located over the two or more branch electrical power lines under the panel and is devoid of being located over the two or more branch circuit breakers;

the array of current sensors are separated from the one or more main electrical power lines by at least the surface of the panel when the array of current sensors is affixed at the region of the surface of the panel; and

the array of current sensors are not electrically coupled or physically coupled to the one or more main electrical power lines or the two or more branch electrical power lines at the panel when the array of current sensors is affixed at the region of the surface of the panel.

2. The method of claim 1, wherein:

calibrating the array of current sensors further comprises;

electrically coupling the at least one known load of the two or more electrical devices to the one or more main electrical power lines; and

the method further comprises;

after calibrating the array of current sensors, uncoupling the at least one known load of the two or more electrical devices from the one or more main electrical power lines; and

keeping the at least one known load of the two or more electrical devices uncoupled from the one or more main electrical power lines while using the array of current sensors, producing the output signal, processing the output signal, sensing the voltage, and computing the electrical power.

3. The method of claim 1, further comprising:

displaying at least one of a magnitude or a representation of the magnitude of the electrical current flowing in the one or more main electrical power lines,

wherein;

processing the output signal comprises;

processing the output signal to determine the magnitude of the electrical current flowing in the one or more main electrical power lines.

4. The method of claim 1, further comprising:

conveying the output signal to a location that is spaced apart from the array of current sensors and the panel.

5. The method of claim 4, wherein:

conveying the output signal to the location uses at least one of;

a wire conductor;

or

a wireless transmitter.

6. The method of claim 1, further comprising:

computing a reactive power for a portion of the electrical current that flows through the first load,

wherein;

the first load is not purely resistive; and

computing the reactive power comprises using a power level to compute the reactive power.

7. The method of claim 6, further comprising:

determining a phase difference between the portion of the electrical current and the voltage.

8. The method of claim 1, further comprising:

displaying the electrical power being provided to the structure,

wherein;

displaying the electrical power being provided to the structure comprises;

displaying at least one of a true power being consumed by the first load, a reactive power being consumed by the first load, or an apparent power being consumed by the first load.

9. The method of claim 8, further comprising:

determining a total amount of energy consumed by the first load during at least one time interval.

10. The method of claim 9, further comprising:

storing at least one of a value or a representation of the value of the total amount of energy consumed during the at least one time interval; and

conveying at least one of the value or the representation of the value of the total amount of energy consumed during the at least one time interval to an entity that determines a payment due for the electrical power provided to the structure.

11. The method of claim 1, wherein:

the array of current sensors comprises;

two or more sensing elements; and

each sensing element of the two or more sensing elements is proximate to a different one of the one or more main electrical power lines.

12. The method of claim 1, wherein:

the array of current sensors comprises at least one of;

a magnetoresistive current sensor;

a Hall effect current sensor;

a fluxgate sensor;

or

an induction coil.

13. The method of claim 1, further comprising:

affixing the array of current sensors to the region on the surface of the panel that is located over the at least the part of the one or more main electrical power lines, wherein the array of current sensors is devoid of being located over the two or more branch electrical power lines under the panel and is being located over the two or more branch circuit breakers,

wherein;

the array of current sensors senses the electrical current flowing in the one or more main electrical power lines using a contactless sensing technique.

14. The method of claim 13, wherein:

the surface of the panel comprises a surface of an electrical circuit breaker panel; and

affixing the array of current sensors to the region on the surface of the panel comprises;

removably attaching the array of current sensors to the region of the surface of the electrical circuit breaker panel.

15. A system for monitoring electrical power usage of a structure, the structure having (a) two or more branch circuit breakers, (b) two or more branch electrical power lines that supply at least a portion of the electrical power to a first load in the structure (c) and one or more main electrical power lines that supply the electrical power to the two or more branch electrical power lines and receive the electrical power from an external power source and the structure further having a panel that overlies at least part of the one or more main electrical power lines and at least part of the two or more branch electrical power lines, the two or more branch electrical power lines are electrically coupled to the one or more main electrical power lines at the two or more branch circuit breakers, the system comprising:

an electrical current sensor that is configured to be attached to a surface of the panel without removing the panel to expose the at least the part of the one or more main electrical power lines or the at least the part of the two or more branch electrical power lines that are covered by the panel, the electrical current sensor also configured to sense an electrical current flowing through the one or more main electrical power lines and further configured to produce an output signal that is indicative of the electrical current flowing through the one or more main electrical power lines;

a processing circuit configured to receive the output signal from the electrical current sensor; and

a calibration circuit configured to be coupled to at least one electrical line of the one or more main electrical power lines,

wherein;

the processing circuit is further configured to calibrate the electrical current sensor by monitoring a magnitude of the electrical current in the one or more main electrical power lines while the calibration circuit is coupled to the at least one electrical line of the one or more main electrical power lines;

the electrical current sensor is configured to be attached to a region of the surface of the panel that is proximate to the at least the part of the one or more main electrical power lines, and that is not at or adjacent to the at least the part of the two or more branch electrical power lines, and that is not at or adjacent to the two or more branch circuit breakers;

the electrical current sensor is not directly physically coupled to the one or more main electrical power lines or the two or more branch electrical power lines at the panel when the electrical current sensor is attached to the region of the surface of the panel;

the electrical current sensor is spaced apart from the one or more main electrical power lines by at least the surface of the panel when the electrical current sensor is attached to the region of the surface of the panel; and

the processing circuit is further configured to process the output signal to determine one or more parameters related to the electrical power usage of the structure.

16. The system of claim 15, further comprising:

a display configured to show a magnitude of at least one of the one or more parameters.

17. The system of claim 15, further comprising:

a wireless transmitter configured to convey the output signal to a location that is spaced apart from the electrical current sensor and the panel,

wherein;

the processing circuit is located at the location.

18. The system of claim 15, further comprising:

a wireless transmitter coupled to the electrical current sensor and configured to wirelessly convey the output signal to the processing circuit,

wherein;

the processing circuit is configured to wirelessly receive the output signal.

19. The system of claim 15, further comprising:

a line plug electrically coupled to the processing circuit and configured to couple the processing circuit to an electrical line socket of the structure,

wherein;

the processing circuit is further configured to detect a voltage on at least one electrical line of the one or more main electrical power lines; and

the electrical line socket is electrically coupled to at least one of the one or more main electrical power lines.

20. The system of claim 15, wherein:

the one or more parameters comprise at least one of;

a magnitude of the electrical current flowing through the one or more main electrical power lines;

or

a magnitude of the at least the portion of the electrical power consumed by the first load,

wherein;

the processing circuit is further configured to determine the magnitude of the at least the portion of the electrical power consumed by the first load.

21. The system of claim 15, wherein:

the processing circuit is further configured to determine a phase difference between at least a portion of the electrical current flowing through at least one of the one or more main electrical power lines and a voltage on the at least one of the one or more main electrical power lines.

22. The system of claim 15, wherein:

the one or more parameters comprise a reactive electrical power;

the first load is not purely resistive; and

the processing circuit is further configured to determine the reactive electrical power.

23. The system of claim 15, wherein:

the processing circuit is further configured to determine a total electrical energy supplied to the first load during a time interval.

24. The system of claim 23, further comprising:

a memory configured to store one or more values for the total electrical energy supplied to the first load during the time interval; and

a communications device for communicating the total electrical energy supplied to the first load during the time interval to at least one of;

an occupant of the structure;

an owner of the structure;

or

an electrical power company providing the at least the portion of the electrical power to the structure.

25. The system of claim 15, wherein:

the electrical current sensor comprises two or more sensing elements that are positioned in the electrical current sensor such that each sensing element of the two or more sensing elements can be proximate to a different one of the one or more main electrical power lines when the electrical current sensor is attached to the surface of the panel.

26. The system of claim 15, wherein:

the panel comprises an electrical circuit breaker panel; and

the electrical current sensor further comprises;

an adhesive backing configured to be removably attached to the surface of the electrical circuit breaker panel such that the electrical current sensor is wirelessly coupled to the one or more main electrical power lines to sense the electrical current flowing through the one or more main electrical power lines.

27. The system of claim 15, further comprising:

a display configured to show the one or more parameters; and

a switch configured to enable a user to select a first parameter of the one or more parameters to appear on the display.

28. The system of claim 15, further comprising:

a first computer comprising a processor comprising the processing circuit,

wherein;

the processing circuit comprises one or more machine instructions configured to run on the processor of the first computer; and

the one or more machine instructions include instructions to determine the one or more parameters related to the electrical power usage of the structure.

31. The system of claim 15, wherein:

the processing circuit is further configured to determine a calibration factor using the magnitude of the electrical current in the one or more main electrical power lines while the calibration circuit is coupled to the at least one electrical line of the one or more main electrical power lines; and

the processing circuit is further configured to process the output signal to determine one or more parameters related to the electrical power usage of the structure, wherein the calibration factor is used to at least partially process the output signal.

29. A system to monitor electrical power usage by one or more electrical devices, the one or more electrical devices coupled to an electrical power infrastructure of a structure, the system comprising:

a power consumption measurement device configured to be coupled to a first surface of a circuit breaker box, the circuit breaker box overlying at least part of one or more electrical supply lines of the electrical power infrastructure, the power consumption measurement device comprising multiple current sensor elements configured to wirelessly sense data related to the electrical power usage by the one or more electrical devices;

a processing module configured to run on a first processor and configured to determine a total electrical power usage by the structure by calculating the electrical power usage of the one or more electrical devices in the structure using the data obtained from the multiple current sensor elements of the power consumption measurement device; and

a calibration load configured to be coupled to at least one electrical line of the one or more electrical supply lines,

wherein;

the electrical power infrastructure comprises two or more branch circuit breakers and the at least part of the one or more electrical supply lines;

the at least part of the one or more electrical supply lines comprise two or more branch electrical power lines and one or more main electrical power lines that are electrically coupled to the two or more branch electrical power lines at the two or more branch circuit breakers;

an electrical current sensor is configured to be affixed at a portion of the first surface of the circuit breaker box that is proximate to the one or more main electrical power lines and is devoid of the two or more branch electrical power lines and devoid of the two or more branch circuit breakers;

the electrical current sensor is further configured to be affixed at the portion of the first surface of the circuit breaker box such that at least the first surface of the circuit breaker box is between the electrical current sensor and the one or more main electrical power lines;

the calibration load is configured to be uncoupled from the at least one electrical line of the one or more electrical supply lines;

each of the multiple current sensor elements comprises an induction coil;

the multiple current sensor elements are not electrically coupled or physically coupled to the one or more main electrical power lines or the two or more branch electrical power lines at the circuit breaker box when the electrical current sensor is affixed at the portion of the first surface of the circuit breaker box;

the power consumption measurement device is configured such that the multiple current sensor elements are positioned such that each of the multiple current sensor elements can be proximate to a different one of the one or more electrical supply lines when the power consumption measurement device is coupled to the first surface of the circuit breaker box;

the processing module is further configured to calibrate the multiple current sensor elements by monitoring a magnitude of an electrical current in the one or more electrical supply lines while the calibration load is coupled to the at least one electrical line of the one or more electrical supply lines;

the processing module is further configured to determine a calibration factor using the magnitude of an electrical current in the one or more electrical supply lines while the calibration load is coupled to the at least one electrical line of the one or more electrical supply lines;

the processing module is further configured to process an output signal to determine one or more parameters related to the electrical power usage of the structure using the calibration factor, the output signal indicative of the data wirelessly sensed by the multiple current sensor elements; and

the processing module is further configured to use the calibration factor to at least partially calibrate the electrical current sensor to account for non-linearities of magnetic fields at the circuit breaker box.

30. A method for sensing electrical power being provided to a structure, the structure having two or more branch circuit breakers, two or more branch electrical power lines that supply at least a portion of the electrical power to a first load of two or more electrical devices in the structure and one or more main electrical power lines that supply the electrical power to the two or more branch electrical power lines and receive the electrical power from an external power generator, the structure further having a panel that overlies at least part of the one or more main electrical power lines and the two or more branch electrical power lines, the first load comprises a total load of all of the two or more electrical devices in the structure that are electrically coupled to the two or more branch electrical power lines, the method comprising:

coupling a current sensor to a region of a surface of the panel that is proximate to the one or more main electrical power lines and is devoid of the two or more branch electrical power lines and devoid of the two or more branch circuit breakers, the current sensor is not electrically coupled or physically coupled to the one or more main electrical power lines or the two or more branch electrical power lines at the panel when the current sensor is coupled to the region of the surface of the panel, the current sensor is separated from the one or more main electrical power lines by at least the surface of the panel when the current sensor is coupled to the region of the surface of the panel;

calibrating the current sensor by detecting a change in a magnitude of an electrical current in the one or more main electrical power lines after at least one known load of the two or more electrical devices has been electrically coupled to the two or more branch electrical power lines;

using the current sensor to sense the electrical current flowing in the one or more main electrical power lines after the at least one known load of the two or more electrical devices has been uncoupled from the two or more branch electrical power lines;

producing an output signal indicative of the electrical current in the one or more main electrical power lines;

processing the output signal to determine the electrical current flowing in the one or more main electrical power lines after the at least one known load of the two or more electrical devices has been uncoupled from the two or more branch electrical power lines;

sensing a voltage on at least one of the one or more main electrical power lines; and

computing the electrical power being provided to the structure using the voltage and the electrical current flowing in the one or more main electrical power lines after at least one known load of the two or more electrical devices has been uncoupled from the two or more branch electrical power lines.