UTILITY METERING

• US 20110153246A1
• Filed: 07/17/2009
• Published: 06/23/2011
• Est. Priority Date: 07/17/2008
• Status: Active Grant

• Current Assignee: Isis Innovation Limited
• Original Assignee: Isis Innovation Limited
• Inventors: Donaldson, James, McCulloch, Malcolm
• Granted Patent: US 8,843,334 B2
• Time in Patent Office: Days
• US Class Current: 702/65
• CPC Class Codes: G01D 2204/24 Identification of individual loads, e.g. by analysing current/voltage waveforms
• CPC Class Codes: G01D 4/00 Tariff metering apparatus in taximeters G07B13/00; apparatus actuated by coins, cards or the like with meter-controlled dispensing of liquid, gas, or electricity G07F15/00
• CPC Class Codes: G01R 21/133 by using digital technique
• CPC Class Codes: G01R 21/1331 Measuring real or reactive component, measuring apparent energy
• CPC Class Codes: G01R 27/02 Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant by measuring phase angle only G01R25/00
• CPC Class Codes: Y04S 20/30 Smart metering, e.g. specially adapted for remote reading

Abstract

An apparatus has an input section arranged to receive values representative of the total instantaneous supply of electrical current as a function of time from an alternating voltage supply. Current waveforms comprising sets of values representative of the cyclic waveform of the electric current supply are obtained. A delta waveform generator calculates the difference between a current waveform and an earlier current waveform. An edge detector is arranged to detect an edge or edges in the delta waveform. An analysis section is arranged to identify at least one appliance load based at least on information on the edge or edges detected by the edge detector, and to determine the electrical energy consumed by said appliance load. Another apparatus has an input section arranged to receive values representative of the current supplied to an installation, such as a house. A store contains appliance data characteristic of the use of electricity by each of a plurality of appliances. A processor is arranged to analyse the received values to detect when an appliance is switched on and determine the fractional change in resistance of a heating appliance from the when it is switched on until it reaches its operating temperature. This information is used to identify what the particular appliance is, and to determine the electrical energy consumption by that appliance. A utility meter for metering the use of at least one utility supplied to a plurality of appliances is also disclosed. An input section is arranged to receive values representative of the use of a first utility. A store contains appliance data characteristic of the use of utilities by each of a plurality of appliances. A processor is arranged to analyse the received values and to determine information on the use of a second utility by each appliance, based on the received values and appliance data.

Claims

1. A variable power load detector apparatus, for use in a non-intrusive electrical load meter for metering the use of electricity supplied to a plurality of loads, the apparatus comprising:

an input section arranged to receive values representative of the total instantaneous supply of electrical current as a function of time from an alternating voltage supply;

a monitor section arranged to determine current waveforms comprising sets of values representative of the cyclic waveform of the electric current supply;

a delta waveform generator arranged to calculate the difference between a current waveform and an earlier current waveform, by subtracting the respective sets of values determined by the monitor section, to obtain a delta waveform;

an edge detector arranged to detect an edge or edges in the delta waveform; and

an analysis section arranged to identify at least one load based at least on information on the edge or edges detected by the edge detector.

2. Apparatus according to claim 1, further comprising an event detector arranged to detect an event representing a change in the total electrical energy being supplied per cycle;

and wherein the delta waveform generator is arranged to calculate the difference between the current waveforms before and after the detected event.

3. Apparatus according to claim 1, wherein the edge detector is further arranged to determine information on the gradient of at least one of the edges.

4. Apparatus according to claim 1, wherein the edge detector is further arranged to determine information on the position of any edges in the delta waveform.

5. Apparatus according to claim 4, wherein the analysis section is further arranged to determine the nominal full power of the at least one load based on the position of at least one detected edge.

6. Apparatus according to claim 1, wherein the edge detector is further arranged to determine information on the number of edges in the delta waveform.

7. Apparatus according to claim 1, wherein the analysis section is further arranged to identify at least one load based on the presently known powers of loads known to the apparatus.

8. Apparatus according to claim 1, wherein the analysis section is arranged to determine the electrical energy consumed individually by each load.

9. Apparatus according to claim 1, wherein the edge detector is arranged to:

correlate the delta waveform with at least a subset of basis waveforms, each basis waveform having a known edge or edges;

identify the basis waveform corresponding to the highest correlation coefficient; and

detect an edge or edges in the delta waveform based on the known edge or edges in the identified basis waveform.

10. Apparatus for metering the use of electricity supplied to a plurality of appliances, the apparatus comprising:

an input section arranged to receive values representative of the total supply of electrical power as a function of time;

a transient detector arranged to detect the time at which an appliance is switched on from a change in the received values due to an increase in the electric power being supplied at that time;

an analysis section arranged to analyse the received values and to determine;

(i) a first value related to the resistance of said appliance at the time of being switched on detected by said transient detector; and

(ii) a second value related to the resistance of said appliance when operating in a steady state; and

a processing section arranged to identify said appliance based on at least said first and second values, and to determine the electrical energy consumed by said appliance.

11. Apparatus according to claim 10, wherein the received values are measurements of current or measurements of current and voltage of the electricity supply.

12. Apparatus according to claim 10, wherein each said value related to the resistance is one of:

the current;

the reciprocal of the current;

the voltage divided by the current;

the voltage multiplied by the current, and

wherein said current values represent the current supplied to said appliance given by the total supply current minus the supply current before the switch on of said appliance detected by the transient detector.

13. Apparatus according to claim 10, wherein the processing section is arranged to calculate a classification value given by:

the difference between the second value and the first value, divided by the first value.

14. Apparatus according to claim 10 wherein the analysis section is further arranged to determine the time duration from when the appliance is switched on until the electrical power being used by the appliance has reached a steady state;

and the identification of said appliance by said processing section is further based on said time duration.

15. Apparatus according to claim 14, wherein the analysis section is arranged to determine a further classification value related to:

the total electrical energy supplied to the appliance from the time of switch on until the time steady state is reached, minus the product of the steady state power and the time from switch on until steady state is reached; and

the identification of said appliance by said processing section is further based on said further classification value.

17. Apparatus according to claim 10, wherein electricity is supplied to a plurality of appliances and said processor is arranged to determine information on the electricity usage by individual ones of said appliances.

16. Apparatus for metering the use of electricity supplied to a plurality of appliances, the apparatus comprising:

an input section arranged to receive values representative of the total supply of electrical power as a function of time;

a transient detector arranged to detect the time at which an appliance is switched on from a change in the received values due to an increase in the electric power being supplied at that time;

an analysis section arranged to analyse the received values and to determine;

(i) the time when the electrical power being used by the appliance has reached a steady state; and

(ii) a classification value related to;

the total electrical energy supplied to the appliance from the time of switch on until the time steady state is reached, minus the product of the steady state power and the time from switch on until steady state is reached;

a processing section arranged to identify said appliance based on at least said classification value, and to determine the total electrical energy consumed by said appliance.

18. Apparatus for metering the use of a utility, the apparatus comprising:

an input section arranged to receive values representative of use of a first utility; and

a processor arranged to analyse the received values and to determine information on the use of a second utility based on the received values; and

an output section for outputting said information.

19. Apparatus according to claim 18, wherein said input section is further arranged to receive values representative of total use of the second utility.

20. Apparatus according to claim 19, wherein said second utility is supplied to a plurality of appliances and said processor is further arranged to determine information on the usage of said second utility by individual ones of said appliances.

21. Apparatus according to claim 20, wherein the processor is arranged to determine information on the use of the second utility by each specific appliance based on inference of the most probable appliance or combination of appliances to be operating based on the received values.

22. Apparatus according to claims 18, wherein the processor is arranged to determine information on the use of the second utility further using known characteristics of the or each appliance to which said second utility is supplied.

23. An apparatus for metering the use of a utility supplied to a plurality of appliances, the apparatus comprising:

an input section arranged to receive, from a sensor, values representative of the total utility being used as a function of time, and to receive time data on the actual time of each sensed value;

a store containing appliance data characteristic of the use of the utility by each of a plurality of appliances;

a processor arranged to analyse the received values and time data, based on the appliance data, and to determine information on the use of the utility by each appliance; and

an output section for outputting said information;

wherein the processor is arranged to determine information on the use of the utility by each appliance based on inference of the most probable appliance or combination of appliances to be operating at a particular time and the most probable magnitude of consumption of the utility by each respective appliance, based on the received values, time data and appliance data; and

wherein the inference uses an inference technique selected from Bayesian inference, neural networks and fuzzy logic.