Compensating apparatus for a non-contact current sensor installing variation in two wire power cable

Patent metadata

Field	Value
Publication number	US-9910070-B2
Application number	US-201314138353-A
Country	US
Kind code	B2
Filing date	Dec 23, 2013
Priority date	Dec 20, 2013
Publication date	Mar 6, 2018
Grant date	Mar 6, 2018

Abstract

A compensating apparatus for installing variation of a non-contact current sensor on a two-wire power cable includes a non-contact current sensor, a sensing element characteristic measuring unit and a non-contact current measurement module. The non-contact current sensor mounted top to the two-wire power cable further has a first current sensor, a second current sensor, and a third current sensor. The sensing element characteristic measuring unit is to construct a space characteristic measuring database for the non-contact current sensor respective to the two-wire power cable. The non-contact current measurement module is to pair the space characteristic measuring database so as to compute and further output a measured value of the current I in the two-wire power cable.

First claim

What is claimed is:

1. An apparatus for compensating installation position variation of a non-contact current sensor on a two-wire power cable, comprising:
a non-contact current sensor, having a first current sensor, a second current sensor, and a third current sensor, the non-contact current sensor being mounted at a top position of a two-wire power cable, a horizontal direction being defined as a direction collinear with a connection line of two centers of corresponding two wires of the two-wire power cable, a vertical direction being defined as a direction perpendicular to the horizontal direction, wherein the first current sensor, located in the vertical direction upper to the two-wire power cable; the second current sensor, located in the vertical direction upper to the first current sensor; the third current sensor is formed by integrating serially two independent coils located in the horizontal direction but oppositely and symmetrically with respect to a center line of the non-contact current sensor;
a sensing element characteristic measuring unit for constructing a space characteristic measuring database for the non-contact current sensor respective to the two-wire power cable, wherein the characteristic measuring database includes a 2D sensor characteristic curve formed by collected signals obtained by moving a 2D sensor structure composed of the first current sensor, the second current sensor and the third sensor via a 2D movable platform; and
a non-contact current measurement module for pairing the space characteristic measuring database so as to compute and further output a measured value of the current I in the two-wire power cable;
wherein the space characteristic measuring database further includes:
a plurality of horizontal displacement indicators, each of the horizontal displacement indicators being a normalized characteristic measuring data set defined by a pair of a horizontal displacement W and the third voltage V 3 ; and
a plurality of vertical displacement indicators, each of the vertical displacement indicators being a respective characteristic measuring data set defined by a pair of the first voltage V 1 /the second voltage

V
2

=

[

V
1

V
2

]

and a

gain
=

[

I

V
1

]

,

wherein the I is the electric current in the two-wire power cable.

2. The apparatus for compensating installation position variation of a non-contact current sensor on a two-wire power cable according to claim 1 , wherein the first current sensor is spaced to the two-wire power cable by a first distance g 1 ; the second current sensor is spaced to the first current sensor by a second distance g 2 ; and a third voltage V 3 is defined as a voltage difference between an input end of the third current sensor and an output end thereof;
wherein the first current sensor and the second current sensor are both coil-type sensors, a first voltage V 1 is defined as a voltage difference between an input end of the first current sensor and an output end thereof, and a second voltage V 2 is defined as a voltage difference between an input end of the second current sensor and an output end thereof.

3. The apparatus for compensating installation position variation of a non-contact current sensor on a two-wire power cable according to claim 2 ,
wherein the sensing element characteristic measuring unit drives the non-contact current sensor located at an upper position of the two-wire power cable to move continuously in a 2D manner along the horizontal direction and the vertical direction, and, according to the Faraday's lay of induction, the current I induced in the two-wire power cable outputs the induced voltages (including the first voltage V 1 , the second voltage V 2 and the third voltage V 3 ) through the first current sensor, the second current sensor and the third current sensor to establish the 2D space characteristic measuring database.

4. The apparatus for compensating installation position variation of a non-contact current sensor on a two-wire power cable according to claim 3 , wherein the non-contact current measurement module further includes:
a measurement counting unit;
a compensation algorithms calculating unit; and
the non-contact current sensor;
wherein the non-contact current sensor is located at an upper position above the two-wire power cable, an electric current I is induced in the two-wire power cable according to the Faraday's law of induction, and the first voltage V 1 , the second voltage V 2 and the third voltage V 3 are captured by the non-contact current sensor so as further to be output to the compensation algorithms calculating unit and further to output a measured value of the current I of the two-wire power cable through the measurement counting unit.

5. The apparatus for compensating installation position variation of a non-contact current sensor on a two-wire power cable according to claim 4 , wherein the compensation algorithms calculating unit further includes:
a first unit, featured by a first function ƒ 1 as a function to locate the first distance g 1 from a 2D variable

(

V
1

V
2

,
W

)

supplied from the 2D space characteristic measuring database, i.e.

g
1

=

f
1

⁡

(

V
1

V
2

,
W

)

⁢

⁢
…
⁢

⁢
the
⁢

⁢
first
⁢

⁢
function
⁢

Assignees

• Ind Tech Res Inst

Inventors

• Cheng Shih Hsien
• Liang Pei Fang
• Cho Lien Yi
• Hsu Wei Hung

Classifications

• G01R35/005

  Calibrating; Standards or reference devices, e.g. voltage or resistance standards, "golden" references (G01R33/0035, G01R35/002 take precedence) · CPC title

• G01R15/142 Primary

  Arrangements for simultaneous measurements of several parameters employing techniques covered by groups G01R15/14 - G01R15/26 · CPC title