UTILISING UAVS FOR DETECTING DEFECTS IN SOLAR PANEL ARRAYS

Abstract

A method and apparatus are provided for detecting defects in a solar panel array (20), using an unmanned aerial vehicle (UAV) (10). The UAV (10) has mounted thereon a pyranometer (12), a GPS receiver (13), a thermographic camera (14), a visual imaging camera (15) and a data logger (16). The method comprises the steps of: (i) mapping the location of panels (22) in a solar array (20); (ii) utilising mapped data collected in step (i) to generate an optimal waypoint flight path (24) for the UAV (10); (iii) transmitting the optimal waypoint flight path data (24) generated in step (ii) to the control means of the UAV (10); (iv) flying the UAV (10) over the solar array (20) using the optimal waypoint flight path (24), whilst simultaneously recording thermographic and visual imagery, and logging solar irradiance and GPS data; and (v) processing data logged in step (iv) to identify and report defective panels (22) by temperature gradient, with cross-referenced solar irradiance data, thermographic and visual imagery and GPS location data.

Claims

1. An unmanned aerial vehicle (UAV) having remotely controllable and/or programmable control means, thereby to direct said UAV's flight path, said UAV having the following components mounted thereon: a thermographic camera; a pyranometer; a global positioning system (GPS) receiver; and a data logger, adapted to log data from at least the pyranometer and the GPS receiver during flight of said UAV.

2. The unmanned aerial vehicle as claimed in claim 1, further having a visual imaging camera mounted thereon.

3. The unmanned aerial vehicle as claimed in claim 2, wherein at least one of the thermographic camera and the visual imaging camera has geo-referencing functionality.

4. The unmanned aerial vehicle as claimed in claim 2, wherein the data logger is further adapted to log data from at least one of the thermographic camera and the visual imaging camera.

5. The unmanned aerial vehicle as claimed in claim 1, wherein the pyranometer and the GPS receiver together form a geo-referencing pyranometer.

6. The unmanned aerial vehicle as claimed in claim 1, wherein the data logger is further adapted to communicate logged data to a remote device during flight.

7. The unmanned aerial vehicle as claimed in claim 6, wherein the data logger is adapted to communicate said logged data over a mobile telecommunications network via a GSM standard signal.

8. (canceled)

9. (canceled)

10. (canceled)

11. Apparatus for detecting and assessing defects in solar panel arrays, said apparatus comprising an unmanned aerial vehicle (UAV) as claimed in claim 1, and at least one remote device in communication therewith.

12. (canceled)

13. Apparatus as claimed in claim 11, comprising an unmanned aerial vehicle having a visual imaging camera mounted thereon and wherein said remote device is further adapted to receive data from at least one of said thermographic camera and said visual imaging camera.

14. Apparatus as claimed in claim 13, comprising a remote device adapted to receive data from said data logger and wherein said remote device comprises a processor adapted to process said data and to report cross-referenced thermographic data and solar irradiance data for a given GPS-referenced location in a solar panel array.

15. (canceled)

16. Apparatus as claimed in claim 14, wherein said remote device is further adapted to process and report visual imaging data for a given GPS-referenced location.

17. Apparatus as claimed in claim 14, wherein said remote device is further adapted to process recorded solar irradiance data, thereby to correct a measured irradiance (E.sub.m) collected in the horizontal plane, to a corrected irradiance (E.sub.c) to allow for the angle of tilt of solar panels in an array.

18. Apparatus as claimed in claim 17, wherein said remote device is further adapted to process recorded thermographic data, thereby to normalise a recorded measured temperature gradient (?T.sub.m) at a corrected irradiance (E.sub.c) to a normalised temperature gradient (?T.sub.n) at a standard irradiance of 1000 W/m.sup.2.

19. Apparatus as claimed in claim 11, comprising a remote device adapted to transmit pre-determined flight path data to said control means.

20. A method for detecting and assessing defects in a solar panel array, using an unmanned aerial vehicle (UAV) as claimed in claim 1, said method comprising performing the steps of: (i) mapping the location of panels in a solar array; (ii) utilising mapped data collected in step (i) to generate an optimal waypoint flight path for said UAV; (iii) transmitting the optimal waypoint flight path data generated in step (ii) to the control means of said UAV; and (iv) flying said UAV over said solar array using the optimal waypoint flight path, whilst simultaneously recording at least thermographic imaging data and logging solar irradiance and GPS data and subsequently: (v) processing data recorded and logged in step (iv), to identify and report defective panels by temperature gradient, with cross-referenced solar irradiance data, thermographic imagery and GPS location data.

21. A method as claimed in claim 20, using an unmanned aerial vehicle having a visual imaging camera mounted thereon, wherein visual imaging data is also recorded in step (iv), and wherein the data processed in step (v) includes cross-referenced visual imagery data from step (iv).

22. A method as claimed in claim 20, wherein step (v) includes processing recorded solar irradiance data, thereby to correct a measured irradiance (E.sub.m) collected in the horizontal plane, to a corrected irradiance (E.sub.c) to allow for the angle of tilt of solar panels in an array.

23. A method as claimed in 22, wherein step (v) further includes processing recorded thermographic data, thereby to normalise a recorded measured temperature gradient (?T.sub.m) at a corrected irradiance (E.sub.c) to a normalised temperature gradient (?T.sub.n) at a standard irradiance of 1000 W/m.sup.2.

24. A method as claimed in claim 20, using apparatus comprising an unmanned aerial vehicle having a visual imaging camera mounted thereon, and one or more remote devices in communication with said unmanned aerial vehicle, wherein thermographic and visual imaging data recorded in step (iv), and solar irradiance and GPS data logged in step (iv) are transmitted to said remote device.

25. (canceled)

26. A method as claimed in claim 24, wherein the generation and transmittal of the optimum waypoint flight in steps (ii) and (iii), and the processing and analysis in step (v) are performed using said remote device.

27. (canceled)

28. (canceled)

Description

[0054] In order that the present invention may be more clearly understood, a preferred embodiment thereof will now be described in detail, though only by way of example, with reference to the accompanying drawings, in which:

[0055] FIG. 1 shows a schematic representation of a preferred embodiment of an unmanned aerial vehicle (UAV) according to the first aspect of the present invention; and

[0056] FIG. 2 shows a schematic representation of the UAV of FIG. 1 in use, carrying out an inspection of a solar panel array.

[0057] Referring first to FIG. 1, there is shown an unmanned aerial vehicle (UAV) 10, according to a preferred embodiment of a first aspect of the present invention. As can be seen, the UAV 10 is of the rotary wing type, having a plurality of rotors 11. The UAV 10 has mounted thereon a number of instruments: a pyranometer 12 for measuring solar irradiance; a GPS receiver 13 for accurately tracking the location of the UAV 10; a thermographic camera 14 for recording thermographic data and images; a visual (RGB) camera 15 for recording visual images; and a data logger 16 for recording data from the pyranometer 12 and the GPS receiver 13. The pyranometer 12 and GPS receiver 13 together form a geo-referencing pyranometer. The thermographic camera 14 and the visual camera 15 also have geo-referencing functionality.

[0058] As hereinbefore discussed, in an alternative arrangement, the visual (RGB) camera 15 may instead be mounted on a second UAV (not shown).

[0059] The UAV 10 is provided with integral control means (not shown), which may be programmable, or remotely controllable, to direct the flight path of the UAV 10.

[0060] The data logger 16 is also adapted to transmit logged solar irradiance and GPS data to a remote device (not shown) during operation of the UAV 10, so that live data can be viewed during a solar array inspection. The thermographic camera 14 and visual camera 15, are adapted also to transmit live video data to a remote device for viewing during flight of the UAV 10.

[0061] The UAV 10 and the remote device together constitute apparatus for detecting defects in solar panel arrays, according to a second aspect of the present invention.

[0062] Referring now to FIG. 2, there is shown the UAV 10 as hereinbefore described with reference to FIG. 1, in use for the inspection of a solar panel array 20. The solar array 20 is made up of several banks 21 of panels, each bank 21 featuring multiple individual solar panels 22.

[0063] A method according to a third aspect of the present invention, for detecting defects in a solar panel array 20, using an unmanned aerial vehicle (UAV) 10, will now be described, with reference to FIGS. 1 and 2.

[0064] Step (i) of the method requires the location of the panels 22 and panel banks 21 in a solar array 20 to be mapped, or geo-referenced. In practice, this step may already have been carried out prior to the inspection process.

[0065] In step (ii), the mapped data collected in step (i) is used to generate an optimal waypoint flight path for the UAV 10. The waypoints 23 and the flight path 24 are illustrated figuratively in FIG. 2.

[0066] Step (iii) is to transmit the optimal waypoint flight path data 24 generated in step (ii) to the control means of the UAV 10. The flight path data 24 will also include flight height (altitude) and speed, which may need to be varied according to conditions at the time of carrying out the inspection.

[0067] The inspection process is then carried out in step (iv) by flying the UAV 10 over the solar array 20, using the optimal waypoint flight path 24. During flight, the thermographic camera 14 records thermographic imaging data for each panel 22, so that temperature gradients can be identified, which may indicate defective panels, or defective areas within a panel 22. At the same time, the pyranometer 12 measures the solar irradiance, whilst the GPS receiver 13 provides a cross-reference of the precise location (and thus the specific panel 22) at which the solar irradiance data was logged. The visual camera 15 also records images of the panels 22 during the inspection process. The data from the pyranometer 12, and the GPS receiver 13 is recorded by the data logger 16, whilst the thermographic camera 14 and visual camera 15 record their geo-referenced data to a local SD memory card.

[0068] The data logger 16 transmits the logged solar irradiance and GPS data via a GSM signal to a remote device for the data processing step (v). The thermographic camera 14 and visual camera 15 also transmit images to the UAV operator via a live video link. Post-flight, a report can be produced, showing cross-referenced thermographic imaging data and visual images, for any panel 22 in the array 20identified by GPS location dataand cross-referenced with the recorded solar irradiance data at the time the thermographic data was captured.

[0069] Any defective panels in the array 20 will present a higher surface temperature than adjacent correctly functioning panels 22, and a temperature gradient can therefore be observed across the defective panel. Depending on the nature of the defect, a temperature gradient may also be observable within a panel 22, in single or multiple cells. However, temperature gradients can also vary where there is a natural fluctuation in solar irradiance during inspection. Measuring the solar irradiance (using the pyranometer 12) at the same time and location (indicated by the GPS receiver 13) as capturing thermographic data (using the thermographic camera 14) enables such naturally occurring temperature variations to be factored into the inspection results, thus increasing the accuracy and value of the defect detection process. Similarly, the recorded visual images (using the visual imaging camera 15) will indicate where observed temperature gradients may be attributable to obstructions on the surface of a panel 22, rather than to a defect.