Group metering system for power meters

• US 20060033488A1
• Filed: 08/02/2005
• Published: 02/16/2006
• Est. Priority Date: 08/10/2004
• Status: Active Grant

• Current Assignee: Analog Devices, Inc.
• Original Assignee: Analog Devices, Inc.
• Inventors: Gandhi, Guljeet S.
• Granted Patent: US 7,236,897 B2
• Time in Patent Office: Days
• US Class Current: 324/142
• CPC Class Codes: G01R 21/133 by using digital technique
• CPC Class Codes: G01R 22/066 Arrangements for avoiding or indicating fraudulent use
• CPC Class Codes: G01R 22/10 using digital techniques

Abstract

A group metering method (and system) for monitoring electrical energy consumption by a plurality of proximate users replaces multiple individual user-meters by a single electronic meter. A single computational engine computes consumed energy values by the users and deploys a single subsection set (display, real time clock, and non-volatile memory) which can be located on a PCB. The system, usable for single or three phase, may be located out of reach from the users to make it tamper proof. Individual ADCs obtain electrical current values (through current transformers,) of power consumed by individual users and cooperate with a single DSP to compute energy consumption by individual users, readable on a common display in round robin fashion. Differences between the sum of energy values consumed by the users and a consolidated energy reading beyond a known threshold are reported as possible user-tampering. Asynchronous communication ports communicate with display units and AMR modules.

Claims

1. A method of individually monitoring electrical energy consumption by a plurality of users connected to a single main power supply source, comprising the steps of:

deriving electrical current values of power consumption by said users;

converting said electrical current values and a voltage from said main power supply into digital values;

digitally processing said digital values for each user by using a common digital signal processor (DSP) over a known number of cycles to obtain consumed energy values for each user; and

,

monitoring said consumed energy values for each user by using a subsection set that is common to all said users.

2. The method as in claim 1, wherein said subsection set selectively includes a real time clock (RTC), an LCD (liquid crystal display) and a nonvolatile memory.

3. The method as in claim 1, configured by software as a group metering system, including the step of separately measuring total energy consumption simultaneously by all said users in a single measurement.

4. The method as in claim 3, wherein the step of separately measuring total energy consumption simultaneously by all said users in a single measurement is done by using said common DSP.

5. The method as in claim 4, including the step of performing comparison of a consumed energy value from said single measurement with a summation value of consumed energy values from all said users, and accepting said monitoring if said comparison shows an error difference less than a predetermined energy value.

6. The method as in claim 5, including the step of reporting possible user-tampering if said comparison shows an error difference more than a predetermined energy value.

7. The method as in claim 1, including the step of powering said monitoring using an on-board switched power supply, wherein said common DSP and said subsections are incorporated into a common printed circuit board (PCB).

8. The method as in claim 1, including using monitored consumed energy values for display and transmission, said method including the step of calibrating said subsection set and display by using a group metering calibration software.

9. The method as in claim 8, including the step of using a programmed current and voltage source for the step of calibrating said monitoring.

10. The method as in claim 1, including the step of using a communication port to connect a common display unit selectively to a summation meter and multiple sub-meters.

11. An electronic metering arrangement for individually monitoring electrical energy consumption by a plurality of proximate users connected to a common main power supply source, said metering arrangement being common to and shared by all said users, said metering arrangement comprising:

means to derive separate electrical phase current values of power consumption by said users;

analog/digital converter means (ADCs) for converting said separate electrical phase current values to digital current values;

a common digital signal processor (DSP) configured for deriving values of electrical energy consumed by each user from said digital current values and a voltage of said main power supply source over a desired time period, said arrangement including a single subsection set that is common to all said users.

12. A metering arrangement as in claim 11, wherein said main power supply source is single phase and wherein said single subsection set selectively includes a real time clock (RTC), an LCD (liquid crystal display) and a nonvolatile memory, said metering arrangement being disposed out of reach by said users.

13. The metering arrangement as in claim 11, including a display unit for selectively showing energy consumption values at any desired time.

14. The metering arrangement as in claim 13, wherein said display comprises an LCD/LED display which can display a combined total energy consumption of all said users, as well as individual users as desired.

15. The metering arrangement of claim 11, including means for performing a comparison of a single combined value of consumed energy for all users with a summation of values of consumed energy for different users, and accepting said monitoring if said comparison shows an error difference less than a predetermined energy value.

16. The metering arrangement of claim 15, including means for reporting possible user-tampering if said comparison shows an error difference more than a predetermined energy value.

17. The metering arrangement of claim 11, including an on-board switched power supply connected for powering said monitoring, wherein said common DSP and said subsections are incorporated into a common printed circuit board (PCB), wherein the PCB includes a chip-set which is a combination of said DSP and six channels simultaneously sampling sigma-delta analog to digital converters.

18. The metering arrangement of claim 13 configured for accepting selective calibration of said subsection set and said display.

19. The metering arrangement of claim 18, including means for transmitting metered information to a remote site for selective processing.

20. The metering arrangement of claim 13, including synchronous communication ports configured to communicate with said display unit or other automatic meter reading module (AMR).

21. The metering arrangement of claim 18, wherein said means to derive separate electrical current values includes current transformers (CTs), said metering arrangement including means using software for compensating phase shift and nonlinearity in said CTs.

22. The metering arrangement of claim 17, wherein the ADCs are daisy chained and connected to said DSP.

23. The metering arrangement of claim 22, wherein the ADCs are disposed in a daisy-chain configuration and connected to said DSP.

24. The metering arrangement of claim 12, wherein a maximum power demand along with a corresponding date and time acquired from said RTC is stored in an EEPROM (electrically erasable programmable read only memory).

25. The metering arrangement of claim 17, including a main summation meter and multiple sub-meters on a common PCB.

26. The metering arrangement as in claim 20, including means to connect a single AMR to a GSM modem, PLC or RF to communicate data from multiple meters without need for an additional concentrator.

27. The metering arrangement as in claim 25, including a communication port to connect a common display unit selectively to be connected to said summation meter and said multiple sub-meters.

39. The metering arrangement as in claim 11, including a display unit for selectively showing energy consumption values at any time, wherein said main power supply source is three phase.

28. An article comprising a storage medium having instructions thereon which when executed by a computing platform result in execution of a method for individually monitoring electrical energy consumption by a plurality of users connected to a single main power supply source, comprising the steps of:

deriving electrical current values of power consumption by said users;

converting said electrical current values and a voltage from said main power supply into digital values;

digitally processing said digital values for each user by using a common digital signal processor (DSP) over a known number of cycles to obtain consumed energy values for each user; and

,

monitoring said consumed energy values for each user by using a subsection set that is common to all said users.

29. A method of individually monitoring electrical energy consumption by a plurality of proximate users all connected to a common single main power supply source, comprising the steps of:

deriving individual electrical current values of power consumption by each of said users;

converting said electrical current values and a voltage value of said main power supply source into digital values for each user by using separate analog to digital converters (ADCs);

digitally processing said digital values for each user over a known time period to obtain consumed energy values for each user by using a common digital signal processor (DSP); and

,

simultaneously monitoring said consumed energy values for each user by using a single subsection set that is common to all said users.

30. The method as in claim 29, wherein said subsection set selectively includes a real time clock (RTC), an LCD (liquid crystal display) and a nonvolatile memory.

31. The method as in claim 29, configured by software as a group metering system, including the step of separately measuring total energy consumption simultaneously by all said users in a single measurement.

32. The method as in claim 31, including the step of performing comparison of a consumed energy value from said single measurement with a summation value of consumed energy values from all said users, and accepting said monitoring if said comparison shows an error difference less than a predetermined energy value.

33. The method as in claim 32, including the step of reporting possible user-tampering if said comparison shows an error difference more than a predetermined energy value.

34. The method as in claim 29, including the step of powering said monitoring using an on-board switched power supply, wherein said common DSP and said single subsection set are incorporated into a common printed circuit board (PCB).

35. The method as in claim 29, including using monitored consumed energy values for display and transmission, said method including the step of calibrating said subsection set and display by using a group metering calibration software.

36. The method as in claim 35, including the step of using a programmed current and voltage source for the step of calibrating said monitoring.

37. The method as in claim 29, including the step of using a communication port to connect a common display unit selectively to a summation meter and multiple sub-meters.

38. An article comprising a storage medium having instructions thereon which when executed by a computing platform result in execution of a method for individually monitoring electrical energy consumption by a plurality of proximate users all connected to a common single main power supply source, comprising the steps of:

deriving individual electrical current values of power consumption by each of said users;

converting said electrical current values and a voltage value of said main power supply source into digital values for each user by using separate analog to digital converters (ADCs);

digitally processing said digital values for each user over a known time period to obtain consumed energy values for each user by using a common digital signal processor (DSP); and

,

simultaneously monitoring said consumed energy values for each user by using a single subsection set that is common to all said users.