Precision flexible current sensor

• US 20080303511A1
• Filed: 05/28/2008
• Published: 12/11/2008
• Est. Priority Date: 11/28/2005
• Status: Active Grant

• Current Assignee: Ladislav Grno
• Original Assignee: Ladislav Grno
• Inventors: Grno, Ladislav
• Granted Patent: US 7,847,543 B2
• Time in Patent Office: Days
• US Class Current: 324/117R
• 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 cylindrical flexible core; and

,

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 or said sensing coil includes a plurality of individually isolated sensing 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, 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 of claim 1, wherein said shielding wires wound in opposite directions are mutually twisted.

5. The flexible current sensor according to claim 1, wherein said sensing wires wound in opposite directions are mutually twisted.

6. The flexible current sensor of claim 1, wherein said sensor cable is a required length portion of continuous cable pre-manufactured on a coaxial cable making machine.

7. An electronic integrator circuit for the flexible current sensor of claim 1 including a differential input stage for said sensing coil.

8. An electronic integrator circuit for the flexible current sensor of claim 1 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.

9. A method for use of the flexible current sensor of claim 1 as means for residual current measurement in large conductor groups.

10. A method for use of the flexible current sensor of claim 1 as means for surge or lightning total and/or partial current measurement in large structures.

11. A method for use of the flexible current sensor of claim 1 as current measurement means within measuring devices.

12. A flexible current sensor including:

a sensing cable with a sensing coil wound on a 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 and said sensing coil includes a plurality of individually isolated sensing wires arranged into groups wound in mutually opposite directions.