Method and System for Measuring/Detecting Ice or Snow Atmospheric Accretion on Overhead Power Lines

• US 20170227677A1
• Filed: 02/03/2017
• Published: 08/10/2017
• Est. Priority Date: 02/04/2016
• Status: Active Grant

• Current Assignee: Ampacimon S.A.
• Original Assignee: Ampacimon S.A.
• Inventors: Godard, Bertrand
• Granted Patent: US 10,451,770 B2
• Time in Patent Office: Days
• CPC Class Codes: G01L 5/102 using sensors located at a non-interrupted part of the flexible member
• CPC Class Codes: G01L 5/107 for measuring a reaction force applied on an element disposed between two supports, e.g. on a plurality of rollers or gliders
• CPC Class Codes: G01L 5/108 for measuring a reaction force applied on a single support, e.g. a glider
• CPC Class Codes: G01N 3/28 Investigating ductility, e.g. suitability of sheet metal for deep-drawing or spinning
• CPC Class Codes: G01W 1/06 giving a combined indication of weather conditions catathermometers for measuring "cooling value" related either to weather conditions or to comfort of other human environment G01W1/17; computers per se G06
• CPC Class Codes: G01W 1/14 Rainfall or precipitation gauges measuring volume in general G01F
• CPC Class Codes: H02G 1/02 for overhead lines or cables
• CPC Class Codes: H02G 7/04 Arrangements or devices for relieving mechanical tension
• CPC Class Codes: H02G 7/16 Devices for removing snow or ice from lines or cables

Abstract

The present invention is related to a method for detecting and/or measuring atmospheric accretion on a suspended electrical cable span (2) of overhead power lines, said suspended electrical cable span (2) having a sag (D) and a local tension (H), and being submitted to wind pressure (w_wind), comprising the steps of independently:

• • measuring said sag (D), and optionally measuring the wind pressure (w_wind), over a first time range,
  • measuring the local tension (H) over a second time range,
    the results of both steps being complemented and/or combined, so that to allow atmospheric accretion detection and/or measurement.

Claims

1. A method for detecting and/or measuring atmospheric accretion on a suspended electrical cable span (2) of overhead power lines, said suspended electrical cable span (2) having a sag (D) and a local tension (H), and being submitted to wind pressure (w_wind), comprising the steps of independently:

measuring said sag (D), and optionally measuring said wind pressure (w_wind), over a first given time range,

measuring said local tension (H) over a second given time range,

the results of both steps being complemented and/or combined, so that to allow atmospheric accretion detection and/or measurement.

2. The method according to claim 1, wherein atmospheric accretion comprises ice, snow, wet snow, frost and the mixtures thereof.

3. The method according to claim 1, wherein the first given time range and the second given time range are the same.

4. The method according to claim 1, wherein the step of measuring the sag (D) of the suspended span (2) is solely obtained by the determination of the fundamental frequency of the electrical cable (1) oscillations.

5. The method according to claim 1, wherein the step of measuring the sag (D) of the suspended span (2) is obtained by an optical method, for example in which a distance to an external target or the ground is measured by a camera located in a device mounted on the suspended span (2).

6. The method according to claim 1, wherein the step of measuring the sag (D) of the suspended span (2) is obtained by an inclinometer method measuring the angle made by the suspended span (2) with the ground.

7. The method according to claim 1, wherein the accretion loading by unit length w_ice [N/m] is given by

8. The method according to claim 7, wherein, in case of negligible wind pressure, the accretion loading by unit length w_ice [N/m] is given by

9. The method according to claim 1, wherein the change of accretion load, and further the change of apparent weight of span (2) due to accretion, over time, is given by:

10. The method according to claim 4, wherein raw tension output data are fitted over the given time range to sag data determined by the method of oscillations fundamental frequency, said time range corresponding to a period with no atmospheric accretion and negligible wind, so that no further calibration is needed for converting raw tension output to actual tension.

11. A device (4) for detecting and/or measuring atmospheric accretion on a suspended electrical cable span (2) of overhead power lines, by carrying out the method according to claim 1, comprising a casing (13, 14) to be traversed by the cable (1), a three-axis accelerometer and a local and internal tension sensor device (8) imposing a deflection to the cable portion traversing the casing (13, 14), yielding a deflected cable portion (17), and providing resulting output strain gauge measurements.

12. Computer program for implementing a method according to claim 1 when executed by a data processing device (5) connected to a sensor set for sensing the motion of at least one point of said suspended cable span (2) over a time interval.

13. Memory carrier containing a computer-readable instruction set for implementing a method according to claim 1 when executed by a data processing device (5) connected to a sensor set for monitoring the motion of at least one point of said suspended cable span (2) over a time interval.