Calibration methods for voltage sensing devices

Patent metadata

Field	Value
Publication number	US-9759798-B2
Application number	US-201414276253-A
Country	US
Kind code	B2
Filing date	May 13, 2014
Priority date	May 13, 2014
Publication date	Sep 12, 2017
Grant date	Sep 12, 2017

Abstract

A calibration method for enhancing a measurement accuracy of one or more voltage sensing devices in presence of a plurality of conductors is provided. The method includes operatively coupling at least one voltage sensing device of the one or more voltage sensing devices to a respective conductor of the plurality of conductors and determining a sensed voltage value of the respective conductor using the at least one voltage sensing device The method further includes determining a calibration matrix having cross-coupling factors representative of cross-coupling between an antenna of the at least one voltage sensing device and other conductors of the plurality of conductors and determining a corrected voltage value of the respective conductor by deducting at least in part contributions of the cross-coupling from the sensed voltage value of the respective conductor using the calibration matrix.

First claim

The invention claimed is:

1. A calibration method for enhancing a measurement accuracy of one or more voltage sensing devices in the presence of a plurality of conductors, the method comprising:
operatively coupling at least one voltage sensing device of the one or more voltage sensing devices to a respective conductor of the plurality of conductors;
determining a sensed voltage value relative to a voltage potential at a reference surface of the respective conductor using the at least one voltage sensing device;
determining a calibration matrix comprising cross-coupling factors representative of cross-coupling between an antenna of the at least one voltage sensing device and other conductors of the plurality of conductors, wherein the at least one voltage sensing device includes:
a first impedance element having a first impedance value, the first impedance element operatively coupled to the antenna and the respective conductor; and
a second impedance element having a second impedance value, wherein the second impedance element is formed in part by the antenna operatively coupled to the first impedance element and only one parasitic impedance element having a parasitic impedance value, and wherein the second impedance value is higher than the first impedance value by a multiple of about 50 (fifty) to about 10,000 (ten thousand); and
determining a corrected voltage value of the respective conductor by deducting at least in part contributions of the cross-coupling from the sensed voltage value of the respective conductor using the calibration matrix.

2. The calibration method of claim 1 , wherein the plurality of conductors are disposed in a determined geometry.

3. The calibration method of claim 1 , wherein the voltage sensing device is a contactless voltage sensing device, wherein the contactless voltage sensing device further includes measurement and communication circuitry coupled to the first impedance element and configured to determine the sensed voltage value of the respective conductor, and wherein the measurement accuracy is not substantially influenced by a presence of at least one object including at least one conductor object between the contactless voltage sensing device and the reference surface.

4. The calibration method of claim 3 , wherein the contactless voltage sensing device further comprises an electrically conductive element configured to provide shielding on one or more sides of the first impedance element.

5. The calibration method of claim 3 , wherein the other conductors of the plurality of conductors are operatively coupled to respective contactless voltage sensing devices, and wherein one or more respective contactless voltage sensing devices comprise an electrically conductive shield.

6. A method for determining individual voltage values of one or more power lines of multi-phase power lines relative to a voltage potential at a reference surface, said method comprising:
operatively coupling respective contactless voltage sensing devices to one or more power lines of the multi-phase power lines, wherein each of the respective contactless voltage sensing devices, comprises:
a first impedance element having a first impedance value, wherein the first impedance element is configured to be operatively coupled to a respective power line of the one or more power lines;
an antenna operatively coupled to the first impedance element;
a second impedance element having a second impedance value, wherein the second impedance element is formed in part by the antenna and only one parasitic impedance element having a parasitic impedance value, and wherein the second impedance value is higher than the first impedance value by a multiple of about 50 (fifty) to about 10,000 (ten thousand); and
measurement and control circuitry operatively coupled to the first impedance element;

determining sensed voltage values for the one or more power lines of the multi-phase power lines using the respective contactless voltage sensing devices;
determining a calibration matrix comprising cross-coupling factors, wherein the cross-coupling factors are representative of cross-coupling between a respective antenna of the respective contactless voltage sensing device and other power lines of the multi-phase power lines; and
determining the individual voltage values of the respective power lines by deducting at least in part contributions of the cross-coupling from the sensed voltage values using the calibration matrix.

7. The method of claim 6 , wherein a relation between the individual voltage values and the sensed voltage values of three power lines in a three-phase power lines is represented by:

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Assignees

• Gen Electric

Inventors

• Kolwalkar Amol Rajaram
• Vartak Sameer Dinkar
• Raghunathan Arun Kumar
• Kulkarni Abhijeet Arvind
• O'Sullivan Charles Brendan

Classifications

• G01R15/144

  Measuring arrangements for voltage not covered by other subgroups of G01R15/14 · CPC title

• G01R35/005 Primary

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

• G01R19/2503

  for measuring voltage only, e.g. digital volt meters (DVM's) (G01R19/2506 - G01R19/257 take precedence) · CPC title