Multi-node electrical power monitoring, analysis, and related services

Patent metadata

Field	Value
Publication number	US-9354271-B2
Application number	US-201414200884-A
Country	US
Kind code	B2
Filing date	Mar 7, 2014
Priority date	May 10, 2013
Publication date	May 31, 2016
Grant date	May 31, 2016

Abstract

The operation of electrical appliances receiving electrical power from an electrical system may be indirectly monitored using monitoring units engaged with outlets on branch circuits of the electrical system. Electrical systems providing power to appliances to be monitored in accordance with the present invention may comprise split phase alternating current systems, tri-phase systems, or any other type of electrical system. Known loads may be applied to calibrate the monitoring system. The monitoring system may measure the power consumption of appliances operating on the electrical system and/or detect possible fault conditions. The application of a known load to each phase of the electrical system for calibration permits different portions of the electrical system to be isolated and, therefor, provides improved accuracy in monitoring power consumption and detection of potential fault conditions.

First claim

The invention claimed is:

1. A method for monitoring electrical appliances drawing power from a an electrical system having multiple phases, the method comprising:
engaging at least two monitoring units with different outlets of an electrical system, the different outlets being on different phases of the electrical system;
at a first monitoring unit of the at least two monitoring units, applying a first calibration load having known electrical properties in a predetermined fashion during a first time frame;
at a second monitoring unit of the at least two monitoring units, applying a second calibration load having known electrical properties in a predetermined fashion during a second time frame, the second time frame not being coincident with the first time frame;
during the first time frame, measuring the variation in voltage in response to the application of the first calibration load at both the first monitoring unit and at the second monitoring unit to provide a first set of calibration measurements;
during the second time frame, measuring the variation in the voltage in response to the application of the second calibration load at both the first monitoring unit and the second monitoring unit to provide a second set of calibration measurements;
at a first plurality of time frames not coincident with either of the first time frame and the second time frame, measuring the voltage at both the first monitoring unit and the second monitoring unit to detect changes in voltage due to an application of an electrical load other than the first calibration load and the second calibration load, the resulting variations in voltage measurements comprising at least a first set of voltage change measurements corresponding to a time when an electrical appliance engaged with an outlet of the electrical system was operational;
using the first set of calibration measurements, the second set of calibration measurements, and the first set of voltage change measurements, calculating the power consumed by the electrical appliance by excluding voltage changes occurring outside of the phases of the electrical system; and
outputting the power consumed by the electrical appliance in a perceivable form.

2. The method of claim 1 , wherein the first time frame is of a length sufficient for transients due to the application of the first calibration load to dissipate and wherein the second time frame is of a length sufficient for transients due to the application of the second calibration load to dissipate.

3. The method of claim 2 , wherein the values of the currents resulting from the application of the first calibration load and the application of the second calibration load are sufficiently different that for constant loads existing on the electrical system a sufficient number of independent equations generated to solve the equation sets for the series and constant load impedances and for the voltage at a power distribution point for the electrical system.

4. The method of claim 2 , further comprising identifying a plurality of distinct electrical appliances that draw power from the electrical system and calculating the power consumed by each electrical appliance independently.

5. The method of claim 4 , further comprising:
storing the first set of calibration measurement, the second set of calibration measurements, the first set of voltage change measurements in a digital storage medium;
accessing a database of expected voltage signatures for electrical appliances;
using the first set of calibration measurements, the second set of calibration measurements, the first set of voltage change measurements, and at least one of the expected voltage signatures from the database, identifying at least one electrical appliance drawing power from the electrical system; and
outputting the identification of an electrical appliance drawing power from the electrical system and the power consumed by the electrical appliance.

6. The method of claim 5 , further comprising:
comparing the first set of voltage change measurements and the expected voltage signatures from the database; and
if the first set of voltage change measurements differs from the expected voltage signature by a predetermined amount, issuing a fault alert in a perceivable form.

7. The method of claim 2 , further comprising receiving data describing the topology and design of the electrical system, and wherein using the first set of calibration measurements, the second set of calibration measurements, the first set of voltage change measurements, excluding voltage drops not on the branch of the electrical system with electrical appliance to calculate the power consumed by the electrical appliance further comprises also using the data describing the topology and design of the electrical system to calculate the power consumed by the electrical appliance.

8. The method of claim 2 , further comprising analyzing the first set of voltage change measurements using blind signal separation techniques to identify individual electrical appliances drawing power from the electrical system.

9. The method of claim 8 , wherein the blind signal separation technique is at least one of Singular Value Decomposition (SVD), Principle Component Analysis (PCA), and Independent Component Analysis (ICA).

10. The method of claim 2 , further comprising analyzing the first set of voltage change measurements to determine a robust result for specific electrical appliances while other electrical appliances remain undetermined by the first set of voltage change measurements.

11. The method of claim 2 , wherein the electrical system comprises a split phase electrical system.

12. The method of claim 2 , wherein the electrical system comprises a tri-phase electrical system.

13. The method of claim 1 , wherein measuring a variation in voltage to provide a first set of calibration measurements, a second set of calibration measurements, and a first set of voltage change measurements further comprises measuring the voltage in relation to the cycle of the electrical system to produce a plurality of voltage measurements.

14. The method of claim 13 , further comprising storing each of the plurality of voltage measurements in bins corresponding when in the cycle of the electrical system the measurement was made.

15. A method for monitoring electrical appliances that draw power from an alternating current electrical system having a plurality of outlets, the method comprising:
at at least one outlet of the alternating current electrical system, making a plurality of voltage measurements between a hot and neutral lines and between neutral and ground lines of the electrical system in a plurality of time windows, different voltage measurements occurring at different known stages of the alternating current cycle;
at at least one outlet of the alternating current electrical system, applying an electrical load having known properties to the alternating current electrical system;
storing information describing at least some of the plurality of voltage measurements in a digital medium with identifiers indicating the phase of the alternating current when the voltage measurement was made and whether the electrical load having known properties was applied to the alternating current electrical system when the measurement was made;
using the stored voltage measurements, calibrating a model of the alternating current electrical system, the calibration relying upon the information describing measured voltage in relation to the cycle of the alternating current both with and without the applied electrical load having known properties, the calibrati

Assignees

• Alarm Com Inc

Inventors

• Kabler Ronald Byron
• Lutes Robert Leon
• Briancon Alain Charles
• Crawford Curtis Scott
• Giacoponello Christopher Allen
• Johnson Jerald Frederic
• Jara-Olivares Victor Andres
• Epard Marc Anthony
• Goldberg Steven Jeffrey
• Lancaster John Berns

Classifications

• G01R35/005

  Calibrating; Standards or reference devices, e.g. voltage or resistance standards, "golden" references (G01R33/0035, G01R35/002 take precedence) · CPC title

• G01R31/2837

  Characterising or performance testing, e.g. of frequency response (transient response G01R27/28) · CPC title

• G01R31/2836 Primary

  Fault-finding or characterising (G01R31/2822 - G01R31/2831 take precedence) · CPC title

• G01D4/008

  Modifications to installed utility meters to enable remote reading · CPC title

• G06Q50/06

  Energy or water supply · CPC title