Transformer-rated electrical meter arrangement with isolated electrical meter power supply

• US 9,766,271 B2
• Filed: 04/07/2014
• Issued: 09/19/2017
• Est. Priority Date: 04/07/2014
• Status: Active Grant

• Current Assignee: Tstm Inc.
• Original Assignee: Tstm Inc.
• Inventors: May, Greg
• Primary Examiner(s): Koval, Melissa
• Assistant Examiner(s): MCDONNOUGH, COURTNEY G
• Application Number:
  US14/246,990
• Publication Number:
  US 20150288175A1
• Time in Patent Office: 1,261 Days
• Field of Search: 361 52
• CPC Class Codes: G01R 1/36 Overload-protection arrangements or circuits for electric measuring instruments
• CPC Class Codes: G01R 11/02 Constructional details
• CPC Class Codes: G01R 22/061 Details of electronic electricity meters

Abstract

An electrical circuit protecting an electrical utility meter used in connection with an electrical supply connection having a plurality of phases is disclosed. The circuit includes a plurality of voltage transformers, each of the plurality of voltage transformers electrically connected between one of the plurality of phases of the electrical supply connection and an input power connection of an electrical meter, and an electrical connection of the electrical meter dedicated to a power supply of the electrical meter.

Claims

1. An electrical circuit protecting an electrical utility meter used in connection with an electrical supply connection having a plurality of phases, the protection circuit comprising:

a plurality of voltage transformers, each of the plurality of voltage transformers including a power line side connection electrically connected to one of the plurality of phases of the electrical supply connection and a meter-side connection electrically connected to an input power connection of an electrical meter; and

a signal transformer electrically connected between one of the plurality of phases of the electrical supply connection and a separate electrical connection of the electrical meter dedicated to a power supply of the electrical meter, the signal transformer comprising a toroidal autotransformer.

2. The electrical circuit of claim 1, wherein the electrical connection includes a signal transformer electrically connected between one of the plurality of phases of the electrical supply connection.

3. The electrical circuit of claim 2, further comprising an electrical meter having a predetermined socket type, the electrical meter including a mapping application reassigning electrical connections based on an electrical service type to which the electrical meter is connected.

4. The electrical circuit of claim 2, wherein the signal transformer has a rating of less than about 20 volt-amperes.

5. The electrical circuit of claim 2, wherein each of the plurality of voltage transformers has a thermal burden of less than about 20 volt-amperes.

6. The electrical circuit of claim 2, wherein at least the plurality of voltage transformers are positioned within a housing mounted in proximity to the electrical meter.

7. The electrical circuit of claim 2, wherein the housing and the plurality of voltage transformers weighs less than approximately two pounds.

8. The electrical circuit of claim 2, wherein each of the plurality of voltage transformers is dedicated to connection between one of the plurality of phases of the electrical supply connection and a voltage measurement element of the electrical meter.

9. The electrical meter of claim 1, wherein the electrical connection comprises a service outlet connection from an electrical service.

10. An electrical meter arrangement installed at a location associated with an electrical service customer, the arrangement comprising:

an electrical meter monitoring power consumption of the electrical service customer, the electrical meter including a plurality of input power connections and having a plurality of voltage measurement elements configured to measure a voltage at a plurality of different phases of an electrical service;

a plurality of voltage transformers, each of the plurality of voltage transformers including a power line side connection electrically connected to one of the plurality of phases of the electrical supply connection and a meter-side connection electrically connected to a corresponding voltage measurement element;

an electrical connection of the electrical meter dedicated to a power supply of the electrical meter; and

a signal transformer electrically connected between one of the plurality of phases of the electrical supply connection and the electrical connection of the electrical meter dedicated to the power supply of the electrical meter, the signal transformer comprising a toroidal autotransformer.

11. The electrical meter arrangement of claim 10, wherein the electrical meter has a format modified to include a dedicated electrical connection between the signal transformer positioned external to the electrical meter and the power supply of the electrical meter.

12. The electrical meter arrangement of claim 10, wherein the signal transformer has a 2:

1 winding ratio.

13. The electric meter arrangement of claim 10, wherein the electric meter comprises a transformer-rated electrical meter.

14. The electrical meter arrangement of claim 10, wherein the plurality of voltage transformers and the signal transformer are positioned external to a housing of the electrical meter.

15. The electrical meter arrangement of claim 10, wherein the electrical service is selected from among a group of electrical service types consisting of:

a four-wire delta service;

a four-wire wye service;

a three-wire wye service; and

a three-wire delta service.

16. The electrical meter arrangement of claim 10, wherein the electrical meter has a format selected from among a group of formats consisting of:

a form 3 format;

a form 4 format;

a form 35 format;

a form 45 format;

a form 55 format;

a form 9 format;

a form 10 format;

a form 39 format;

a form 26 format;

a form 29 format;

a form 46 format;

a form 56 format;

a form 66 format; and

a form 76 format.

17. The electrical meter arrangement of claim 10, wherein the plurality of voltage transformers weighs less than about two pounds.

18. A method of managing electrical connections to an electrical meter associated with delivery of an electrical service to a customer premises by a user, the method comprising:

electrically connecting a different voltage transformer of a plurality of voltage transformers to each of a plurality of phases of the electrical service;

electrically connecting each of the plurality of voltage transformers to a voltage measurement element of an electrical meter;

electrically connecting a signal transformer to one of the plurality of phases of the electrical service; and

electrically connecting the signal transformer to a power supply of the electrical meter in the absence of connecting the signal transformer between a voltage transformer of the plurality of voltage transformers and the corresponding voltage measurement element;

wherein the signal transformer is electrically connected between one of the plurality of phases of the electrical service and a connection of the electrical meter associated with the corresponding voltage measurement element, the signal transformer comprising a toroidal autotransformer.

19. The method of claim 18, wherein the user comprises a service person associated with the electrical service.

20. The method of claim 19, wherein, upon electrically connecting the plurality of voltage transformers and the signal transformer, the service person does not require protective gear to perform maintenance on the electrical meter.

21. The method of claim 18, wherein electrically connecting the different voltage transformer of a plurality of voltage transformers to each of the plurality of phases of the electrical service comprises mounting a housing for the plurality of voltage transformers in proximity to the electrical meter.