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

• US 9,671,434 B2
• Filed: 08/08/2014
• Issued: 06/06/2017
• Est. Priority Date: 08/08/2014
• Status: Active Grant

• Current Assignee: Aclara Meters LLC (Hubbell, Inc.)
• Original Assignee: Aclara Meters LLC (Hubbell, Inc.)
• Inventors: Bietz, Steven Lee, Chamarti, Subramanyam Satyasurya
• Primary Examiner(s): ALLGOOD, ALESA M
• Application Number:
  US14/454,861
• Publication Number:
  US 20160041204A1
• Time in Patent Office: 1,033 Days
• CPC Class Codes: G01R 15/18 using inductive devices, e.g. transformers
• CPC Class Codes: G01R 15/181 using coils without a magnetic core, e.g. Rogowski coils
• CPC Class Codes: G01R 15/186 using current transformers with a core consisting of two or more parts, e.g. clamp-on type G01R15/142 - G01R15/16 take precedence; tong testers G01R1/22
• CPC Class Codes: G01R 19/00 Arrangements for measuring currents or voltages or for indicating presence or sign thereof G01R5/00 takes precedence; for measuring bioelectric currents or voltages A61B5/24
• CPC Class Codes: G01R 19/0092 measuring current only all subgroups of G01R19/00 take precedence
• CPC Class Codes: H01F 38/28 Current transformers

Abstract

A sensor device for use in detecting current in a conductor is provided. The sensor includes a non-magnetic substrate defining an aperture structured to receive a conductor therein, a coil comprising a plurality of turns wound about at least a portion of the substrate, and a housing for enclosing the substrate and coil. The housing includes a dielectric material having a dielectric constant and positioned adjacent to the coil and at least partially within the aperture such that the dielectric material is disposed between the coil and the conductor when the conductor is received through the aperture and at least one spacer coupled to the aperture to facilitate maintaining a position of the coil relative to the conductor, wherein each of the spacers is positioned offset from the dielectric material such that each of the spacers does not radially extend between the coil and the conductor.

Claims

1. A sensor device for use in detecting current in a conductor, said sensor device comprising:

a non-magnetic substrate defining an aperture through which a conductor is received;

a coil comprising a plurality of turns wound about at least a portion of said substrate; and

a housing enclosing said substrate and said coil, said housing including the aperture formed by said non-magnetic substrate and comprising;

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

an offset ring fitting within said aperture with an outer end of the offset ring projecting perpendicular to an outer face of said housing for said ring to be offset from said housing, said offset ring including at least one spacer extending between said offset ring and said conductor so to maintain a position of said coil relative to said conductor, said spacer extending into said aperture from said outer end of said offset ring so to be offset from said aperture, said offset ring ensuring that said sensor device is spaced a distance away from any object in a meter with which said sensor device is used.

2. The sensor device of claim 1, wherein said housing is installed in a meter housing and the sensor device includes at least one rotational positioner positioned so as to prevent the sensor device from rotating around said conductor.

3. The sensor device of claim 1, wherein said non-magnetic substrate comprises a plurality of bobbins, said plurality of bobbins defining said aperture, and said coil comprises a plurality of coil turns wound about each of said plurality of bobbins.

4. The sensor device of claim 1, wherein said dielectric material comprises a first side and a second side, said first side defining said aperture disposed between said conductor and said coil and comprising a first thickness, wherein said second side extends perpendicular to said first side and comprises a second thickness which is less than said first thickness, said second side attaching to said first side along an edge which is beveled in relation to said first side, and said second side and said edge resulting in an edge thickness which varies between said first thickness and said second thickness.

5. The sensor device of claim 1, wherein the housing further comprises an epoxy which is positioned between said dielectric material and said coil, for said epoxy to attach said coil to said dielectric material.

6. The sensor device of claim 5, wherein said epoxy cures at room temperature.

7. The sensor device of claim 1, wherein said offset ring includes three spacers circumferentially spaced around said offset ring and extending between said offset ring and said conductor so to maintain the position of said coil relative to said conductor, each said spacer extending into said aperture from said outer end of said offset ring so to be offset from said aperture.

8. The sensor device of claim 7, wherein said housing further comprises a first portion and a second portion, said second portion coupling to said first portion so to enclose said coil within the housing, said first portion and said second portion overlapping each other.

9. The sensor device of claim 8, wherein said second portion comprises at least one clip and said first portion comprises at least one retaining portion, wherein said at least one clip couples to said at least one retaining portion to couple said first portion to said second portion, and wherein when said first portion is coupled to said second portion said at least one clip is flush with the first portion.

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

said utility meter comprising;

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

a non-magnetic substrate defining an aperture structured to receive said first conductor therein;

a coil comprising a plurality of turns wound about at least a portion of said substrate; and

a housing enclosing said substrate and said coil, said housing comprising;

a dielectric material having a dielectric constant and positioned adjacent to said coil and at least partially within said aperture defined by said non-magnetic substrate for said dielectric material to be disposed between said coil and said first conductor when said first conductor is received through said aperture;

an offset ring fitting within said aperture with an outer end of the offset ring projecting perpendicular to an outer face of said housing for said ring to be offset from said housing, said offset ring including at least one spacer extending between said offset ring and said first conductor to maintain a position of said coil relative to said first conductor, said spacer extending into said aperture from said outer end of said of said offset ring so to be offset from said aperture, said offset ring ensuring that said sensor device is spaced a distance away from any object in a meter with which said sensor device is used; and

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

wherein said first sensor device is positioned relative to said first conductor to reduce a sensitivity of said first sensor device such that said meter control board requires only one calibration coefficient for calibrating said first sensor device over a current range which extends from approximately 0.2 A to approximately 25,000 A.

11. The utility meter of claim 10, wherein the housing further comprises an epoxy positioned between said dielectric material and said coil, said epoxy attaching said coil to said dielectric material.

12. The utility meter of claim 10, wherein the housing includes at least one rotational positioner positioned to prevent the sensor device from rotating around said first conductor.

13. The utility meter of claim 10, wherein said non-magnetic substrate comprises a plurality of bobbins defining said aperture and said coil comprises a plurality of coil turns wound about each of said plurality of bobbins.

14. The utility meter of claim 10, wherein said dielectric material comprises a first side and a second side, said first side defining said aperture and being disposed between said conductor and said coil and having a first thickness, wherein said second side extends perpendicular to said first side and comprises a second thickness which is less than said first thickness, said second side attaching to said first side along an edge which is beveled in relation to said first side, and said second side and said edge resulting in an edge thickness which varies between said first thickness and said second thickness.

15. The utility meter of claim 10, further comprising a second sensor device also in communication with said meter control board, wherein said second sensor device is positioned at least partially around a second conductor, wherein said first sensor device is positioned relative to said second sensor device so to reduce the sensitivity of said first sensor device and a sensitivity of said second sensor device whereby said meter control board requires only one calibration coefficient for calibrating each of said first and second sensor devices over said current range.

16. The utility meter of claim 15, further comprising a third sensor device also in communication with said meter control board, wherein said third sensor device is positioned at least partially around a third conductor, wherein said first sensor device is positioned relative to said second sensor device and said third sensor device so to reduce the sensitivities of said first sensor device, said second sensor device, and said third sensor device whereby said meter control board requires only one calibration coefficient for calibrating each of said first, second, and third sensor devices over said current range.

17. The utility meter of claim 10, wherein said offset ring includes three spacers circumferentially spaced about said offset ring and extending between said offset ring and said conductor so to maintain the position of said coil relative to said conductor, each said spacer extending into said aperture from said outer end of said offset ring so to be offset from said aperture.

18. The utility meter of claim 17, wherein said housing further comprises a first portion and a second portion, said second portion coupling to said first portion so to enclose said coil within the housing, said first portion and said second portion overlapping each other.

19. The utility meter of claim 18, wherein said second portion comprises at least one clip and said first portion comprises at least one retaining portion, wherein said at least one clip couples to said at least one retaining portion to couple said first portion to said second portion, and wherein when said first portion is coupled to said second portion said at least one clip is flush with the first portion.

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

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

forming a coil comprising a plurality of turns wound about a non-magnetic substrate, said coil defining an aperture through which said first conductor is received, and enclosing in a housing said coil and said non-magnetic substrate, wherein enclosing in said housing comprises;

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

positioning an offset ring within said aperture with an outer end of said offset ring projecting perpendicular to an outer face of said housing for said ring to be offset from said housing, said offset ring including at least one spacer extending between said offset ring and said first conductor so to maintain a position of said coil relative to said first conductor, said spacer extending into said aperture from said outer end of said offset ring so to be offset from said aperture, said offset ring ensuring that said sensor device is spaced a distance away from any object in a meter with which said sensor device is used;

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

positioning said first sensor device relative to said first conductor to reduce a sensitivity of said sensor device whereby said meter control board requires only one calibration coefficient for calibrating said sensor device over a current range extending between approximately 0.2 A and approximately 25,000 A.

21. The method of claim 20, further comprising positioning said first device relative to a second sensor device, wherein said second sensor device is positioned at least partially around a second conductor and said second sensor device is connected to said meter control board, wherein said first sensor device is positioned relative to said second sensor device to reduce the sensitivity of said first sensor device and a sensitivity of said second sensor device whereby said meter control board requires only one calibration coefficient for calibrating each of said first and second sensor devices over said current range.

22. The method of claim 21, further comprising positioning said first sensor device relative to said second sensor device and further relative to a third sensor device, wherein said third sensor device is positioned at least partially around a third conductor and said third sensor device is connected to said meter control board, wherein said first sensor device is positioned relative to said second sensor device and said third sensor device to reduce the sensitivity of said first sensor device, the sensitivity of said second sensor device, and a sensitivity of said third sensor device whereby said meter control board requires only one calibration coefficient for calibrating each of said first, second and third sensor devices over said current range.

23. A sensor device for use in detecting current in a conductor, said sensor device comprising:

a non-magnetic substrate defining an aperture through which a conductor is received;

a coil comprising a plurality of turns wound about at least a portion of said substrate; and

a housing enclosing said substrate and said coil, said housing including the aperture formed by said non-magnetic substrate and comprising;

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

an offset ring fitting within said aperture with an outer end of the offset ring projecting perpendicular to an outer face of said housing for said ring to be offset from said housing, said offset ring including three spacers circumferentially spaced around said offset ring and extending between said offset ring and said conductor so to maintain the position of said coil relative to said conductor, each said spacer extending into said aperture from said outer end of said offset ring so to be offset from said aperture, and each spacer being shaped as a crushed rib with a curved point.