Precision flexible current sensor

• US 7,847,543 B2
• Filed: 05/28/2008
• Issued: 12/07/2010
• Est. Priority Date: 11/28/2005
• Status: Expired due to Fees

• Current Assignee: Ladislav Grno
• Original Assignee: Ladislav Grno
• Inventors: Grno, Ladislav
• Primary Examiner(s): Nguyen; Ha Tran T
• Assistant Examiner(s): BENITEZ ROSARIO, JOSHUA
• Application Number:
  US12/154,921
• Publication Number:
  US 20080303511A1
• Time in Patent Office: 923 Days
• Field of Search: 324/117.H, 324126-127, 324250-253, 336173-177, 336/180, 336/182, 336/188, 336220-221, 336/229
• US Class Current: 324/253
• CPC Class Codes: G01R 15/181 using coils without a magnetic core, e.g. Rogowski coils

Abstract

A flexible current sensor including a sensing cable with a sensing coil wound on a cylindrical flexible core and electrical shielding located over said sensing coil and an outer isolation coat. The electrical shielding includes a plurality of individually isolated shielding wires arranged into groups wound in mutually opposite directions and/or the sensing coil includes a plurality of individually isolated sensing wires arranged into groups wound in mutually opposite directions.

Claims

1. A flexible current sensor including:

a sensing cable with a sensing coil wound on a single cylindrical flexible core;

electrical shielding located over said sensing coil; and

,

an outer isolation coat, wherein said electrical shielding includes a plurality of individually isolated shielding wires arranged into groups wound in mutually opposite directions.

2. The flexible current sensor of claim 1, wherein said shielding wires are mutually electrically interconnected in parallel and wherein each shielding wire has only one connection point.

3. The flexible current sensor according of claim 1, including a plurality of individually isolated sensing wires arranged into groups wound in mutually opposite directions, wherein said sensing wires, respective to voltages induced in sensing wires by magnetic field of sensed current, are electrically interconnected in series or in parallel or combination of series and parallel or some sensing wires remain idle respective to voltages induced in sensing wires by magnetic field of sensed current, wherein configuration of said sensing wires is determined by required sensitivity, impedance and frequency range of said current sensor.

4. The flexible current sensor according to claim 3, wherein said sensing wires wound in opposite directions are mutually twisted.

5. The flexible current sensor of claim 3, wherein said sensor cable is a required length portion of continuous cable pre-manufactured on a coaxial cable making machine.

6. An electronic integrator circuit for the flexible current sensor of claim 3 including a differential input stage for said sensing coil.

7. An electronic integrator circuit for the flexible current sensor of claim 3 including a matched termination of said sensing coil with impedance having value approximately equal to wave impedance of the transmission line represented by said sensing coil.

8. A method for use of the flexible current sensor of claim 3 as means for residual current measurement in large conductor groups.

9. A method for use of the flexible current sensor of claim 3 as means for surge or lightning total and/or partial current measurement in large structures.

10. A method for use of the flexible current sensor of claim 3 as current measurement means within measuring devices.

11. The flexible current sensor of claim 1, wherein said shielding wires wound in opposite directions are mutually twisted.

12. A flexible current sensor including:

a single cylindrically shaped flexible core;

a plurality of individually isolated sensing wires arranged into groups wound in mutually opposite directions about the flexible core;

a plurality of individually isolated shielding wires arranged into groups wound in mutually opposite directions about the flexible core; and

,

an outer isolation coat.

13. A flexible current sensor comprising:

a sensing cable including a single cylindrical flexible core; and

,

a plurality of coaxial sensing coil pairs forming first and second coaxial groups of individually isolated sensing wires, wherein;

each said coaxial sensing coil pair includes respective first and second individually isolated sensing wires;

said first individually isolated sensing wires are wound along said single cylindrical flexible core in a first direction; and

,

said second individually isolated sensing wires are wound along said single cylindrical flexible core in a second direction, opposite the first direction.