Sensor devices and methods for use in sensing current through a conductor

• US 8,829,888 B2
• Filed: 09/09/2011
• Issued: 09/09/2014
• Est. Priority Date: 09/09/2011
• Status: Active Grant

• Current Assignee: Aclara Meters LLC (Hubbell, Inc.)
• Original Assignee: General Electric Company
• Inventors: Chamarti, Subramanyam Satyasurya, Bietz, Steven Lee
• Primary Examiner(s): Koval, Melissa
• Assistant Examiner(s): Miller, Daniel
• Application Number:
  US13/229,038
• Publication Number:
  US 20130063125A1
• Time in Patent Office: 1,096 Days
• Field of Search: None
• US Class Current: 324/76.11
• CPC Class Codes: G01R 1/18 Screening arrangements against electric or magnetic fields, e.g. against earth's field
• CPC Class Codes: G01R 11/24 Arrangements for avoiding or indicating fraudulent use
• CPC Class Codes: G01R 15/181 using coils without a magnetic core, e.g. Rogowski coils

Abstract

Sensor devices and related methods disclosed. One example sensor device includes a non-magnetic substrate, a coil comprising a plurality of turns wound about the substrate, the coil defining an aperture structured to receive a conductor therein; and a dielectric material positioned adjacent to the coil and at least partially within the aperture such that the dielectric material is between the coil and a conductor positioned in the aperture.

Claims

1. A utility meter for use in transmitting electrical energy from a power source to a user;

said utility meter comprising;

a sensor device positionable at least partially around a conductor to sense a current flowing through said conductor and to output a signal representative of said sensed current, said sensor device comprising;

a non-magnetic substrate;

a coil comprising a plurality of turns wound about said substrate, said coil defining an aperture through which said conductor is to be received; and

a dielectric material having a dielectric constant and positioned adjacent to said coil and at least partially within said aperture such that said dielectric material is disposed between said coil and said conductor when said conductor is received through said aperture; and

a meter control board in communication with said sensor device to receive said signal representative of said sensed current from said sensor device and to determine an amount of electricity transmitted through said conductor from said power source to said user over time;

wherein said dielectric constant of said dielectric material is selected to reduce a capacitive coupling between said coil and said conductor and to consequently reduce a sensitivity of said sensor device such that said meter control board comprises only one calibration coefficient for calibrating said sensor device over a voltage range and current range;

wherein said voltage range is about 60V to about 600V; and

wherein said current range is about 0.1A to about 200A.

2. The utility meter of claim 1, wherein said dielectric material encloses at least a portion of said coil and at least a portion of said substrate.

3. The utility meter of claim 2, wherein the sensor device comprises a mount forming a friction fit with said conductor, wherein said mount defines at least one air-gap between said sensor device and said conductor, and wherein the mount comprises at least a portion of said dielectric material.

4. The utility meter of claim 3, wherein said sensor device is configured to sense current through said conductor within about ±

0.2% of an actual current through said conductor in a current range between of about 2.0 Amps to about 200 Amps at a voltage of about 240V.

5. The utility meter of claim 3, wherein said substrate comprises a plurality of bobbins, wherein at least one of said plurality of turns is disposed about each of said plurality of bobbins and wherein each of said plurality of bobbins comprise a thermoplastic material.

6. The utility meter of claim 5, wherein said conductor includes one of a bus bar and a multi-strand conductor.

7. The utility meter of claim 1, wherein said dielectric material comprises at least one of a thermoplastic material and a thermoset material.

8. The utility meter of claim 7, wherein said dielectric material comprises at least one of a polyethylene terephthalate (PET) material and a polybutylene terephthalate (PBT) thermoplastic material.

9. The utility meter of claim 1, wherein said substrate comprises a plurality of bobbins, at least one of said plurality of turns is wound about each of said plurality of bobbins.

10. The utility meter of claim 1, further comprising a mount positioned at least partially within said aperture, said mount configured to support a conductor positioned in said aperture, and wherein said mount is fabricated at least partially from said dielectric material.

11. The utility meter of claim 10, further comprising an enclosure at least partially enclosing said substrate and said coil, said enclosure comprising said mount.

12. A method of fabricating a utility meter for use in transmitting electrical energy from a power source to a user, said method comprising:

providing a sensor device positionable at least partially around a conductor to sense a current flowing through said conductor and to output a signal representative of said sensed current, wherein providing said sensor device comprises;

forming a coil comprising a plurality of tums wound about a non-magnetic substrate, said coil defining an aperture through which said conductor is to be received, and

positioning a dielectric adjacent to said coil and at least partially within said aperture such that said dielectric material is disposed between said coil and said conductor when said conductor is received through said aperture; and

connecting a meter control board with said sensor device to receive said signal representative of said sensed current from said sensor device and to determine an amount of electricity transmitted through said conductor from said power source to said user over time;

selecting said dielectric material such that a dielectric constant of said dielectric material reduces a capacitive coupling between said coil and said conductor and consequently reduces a sensitivity of said sensor device such that said meter control board comprises only one calibration coefficient for calibrating said sensor device over a voltage range and current range;

wherein said voltage range is about 60V to about 600V; and

wherein said current range is about 0.1A to about 200A.

13. The method of claim 12, wherein positioning the dielectric material adjacent to the coil includes at least partially enclosing the coil within an enclosure, said enclosure comprising the dielectric material.

14. The method of claim 12, wherein forming the coil includes winding at least one turn of the coil on each of a plurality of bobbins of the substrate.