Electronic metering device including automatic service sensing

• US 5,631,554 A
• Filed: 07/31/1995
• Issued: 05/20/1997
• Est. Priority Date: 03/26/1993
• Status: Expired due to Term

• Current Assignee: Itron, Inc.
• Original Assignee: Schlumberger Industries Incorporated (SLB)
• Inventors: Schlarb, John M., Lowe, Coy S., Hyder, Charles C., Briese, Forrest W., Fouquet, Christophe J. A.
• Primary Examiner(s): Wieder, Kenneth A.
• Assistant Examiner(s): BOWSER, BARRY
• Application Number:
  US08/509,367
• Time in Patent Office: 659 Days
• Field of Search: 364/571, 364/483, 324/142, 324/76.77, 324/141
• US Class Current: 324/76.77
• CPC Class Codes: G01D 18/00 Testing or calibrating apparatus or arrangements provided for in groups G01D1/00 - G01D15/00
• CPC Class Codes: G01D 3/08 with provision for safeguarding the apparatus, e.g. against abnormal operation, against breakdown
• CPC Class Codes: G01D 4/002 Remote reading of utility meters
• 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 21/1335 Tariff switching circuits
• CPC Class Codes: G01R 22/00 Arrangements for measuring time integral of electric power or current, e.g. electricity meters
• CPC Class Codes: G01R 22/10 using digital techniques
• CPC Class Codes: G01R 35/04 of instruments for measuring time integral of power or current
• CPC Class Codes: G06Q 50/06 Energy or water supply
• CPC Class Codes: Y02B 90/20 Smart grids as enabling technology in buildings sector smart grids supporting the management or operation of end-user stationary applications in general, or like technologies with no associated climate change mitigation effect Y04S20/00
• CPC Class Codes: Y04S 20/30 Smart metering, e.g. specially adapted for remote reading

Abstract

An integral electronic meter system diagnostics package including a microprocessor, storage memory, pre-select series of system diagnostic tests, and recording any results which exceed predefined programmable thresholds, and display means for displaying error and/or diagnostic messages identifying selected diagnostic data and/or errors discovered in the meter tests during a predefined period. The system automatically senses the type of electrical service in which the meter is installed.

Claims

1. An electronic meter checking an electrical system diagnostics package including:

a microprocessor;

storage memory suitably connected to the microprocessor;

logic for automatically periodically performing a preselected test of meter checks and recording any errors detected therefrom;

logic for automatically periodically performing a preselected series of system diagnostics tests and recording any results which exceed predefined thresholds;

display means for displaying error messages identifying one or more errors discovered as a result of the meter checks performed during a predefined period; and

display means for displaying diagnostic messages identifying any errors discovered as a result of the system diagnostics tests performed during a predefined period.

2. The system of claim 1 further including logic for automatically determining the type of electrical service in which the meter is installed.

3. The system of claim 2 wherein the logic for automatically determining the type of electrical service in which the meter is installed performs such determination during initialization of the meter upon installation of the meter.

4. The system of claim 3 wherein the logic for automatically determining the electrical service in which the meter is installed performs such determination upon reconfiguration of the meter.

5. The system of claim 2 wherein the logic for determining the electrical service in which the meter is installed automatically periodically performs such determination during normal operation of the meter.

6. An electronic meter system checking and troubleshooting package for ascertaining voltage information from a polyphase electrical system metered thereby, including:

(a) a microprocessor;

(b) storage memory suitably connected to said microprocessor and

(c) logic for automatically determining the type of polyphase electrical system in which a meter including the system checking and troubleshooting package is installed.

7. The system of claim 6, further including logic for ascertaining voltage information from the polyphase electrical system metered thereby.

8. The system of claim 7, wherein said logic for ascertaining voltage information from the polyphase electrical system metered thereby includes logic for determining the phase angle of at least one voltage phasor of the polyphase electrical system metered thereby relative to a selected base voltage phasor, and wherein the logic for automatically determining the type of polyphase electrical system in which the meter including the system checking and troubleshooting package is installed includes logic for comparing the voltage phase angle of the at least one phasor relative to the selected base phasor to a set of preselected voltage phasor angles for different possible types of electrical services, and determining the type of electrical service, if any, as a function of the voltage phasor angle.

9. The system of claim 8 wherein the logic for determining the type of electrical service makes such determination on the basis of the angle between the C phase voltage phasor, V_c, and the A phase voltage phasor, V_a, as well as the predefined form factor of the meter.

10. The system of claim 9 wherein the logic for determining the phase angle of at least one phasor relative to a selected base phasor includes logic for storing accumulated digital values corresponding to the instantaneous voltage measured for the base phasor X_B, storing the accumulated digital values corresponding to the instantaneous value measured for another selected phasor, X_N, determining, for a predefined period, the RMS values for X_B and X_N, denoted X_B(RMS) and X_N(RMS), respectively, determining the product, P, of X_B(RMS) and X_N(RMS), determining the average value, Q, of the product of the two sine waves corresponding to X_B and X_N, and determining the average value, Y, of the product of the two sine waves corresponding to a shifted version of X_B, denoted X_B(-90).

11. The system of claim 10 wherein the logic further includes logic for determining the magnitude of the phase angle of one phasor relative to the selected base phasor, θ

, equal to arccos (Q/P).

12. The system of claim 11 wherein the base phasor, X_B, is the A phase voltage phasor, and wherein the other selected phasor, X_N, is the C phase voltage phasor.