PV systems can be quickly and easily checked for hotspots with

PV systems can be quickly and easily checked for hotspots with

IR-multicopter drone:
Inspection of PV systems
Partners:
13th National Photovoltaic Conference, March 2015, Basel
Prof. Urs Muntwyler, Manuel Lanz
The drone system
The drone is composed of a
multicopter with flight control and
camera equipment from a thermal
imaging camera and a compact
camera. The cameras are stabilized
and aligned with a gimbal, which is
adjusted by remote control.
The video signal is sent to a monitor
on the remote control so that the
pilot knows what the cameras are
recording. Image 1 shows the
complete drone, ready for takeoff.
Image 2: IR-camera system Source: OPTRIS
3
30
2.5
25
2
20
1.5
15
1
10
0.5
Another advantage is the price. The
entire drone system including
accessories costs about the same as
a comparable stand-alone thermal
imaging camera.
5
0
0
0
5
10
15
20
25
Voltage [V]
Siemens
M55M55
Referenzmodul
SIEMENS
reference
module
Siemens
M55
Referenzmodul
SIEMENS
M55
reference(Leistung)
module
(power)
defektes
M55SIEMENS
Modul
Defective
M55 module
defektes
M55SIEMENS
Modul (Leistung)
Defective
M55 module
(power)
Image 4: Characteristic of a defective
module ooooiiiiiiii
Application
For the measurements best weather
conditions are required not only for
the operation of the drone, but also
for thermal imaging inspection of a
PV system. In the infrared imaging,
temperature irregularities are immediately visible and distinguishable
(Image 3, bright spots).
Several flaws can be recognized:
• Strings that are not in operation
• Substrings bridged by bypass
diodes
• Individual cells with various
defects (which could cause a fire)
• Smaller areas than the cell size
Remarkable is the amount of time it
takes to IR-map solar power plants.
For a facility the size of 560kW a
flying time of about 15 minutes is
required.
Especially
for
large
systems, the time difference to
manual checking is wide. For
systems difficult to access, the
advantage of the drone is its
flexibility. It must be made no
further
efforts
to
reach
a
photovoltaic
roof
system,
for
example.
Future Efforts
The drone system will be used for
checking the Facilities of Berne
University of Applied Sciences and
tested at further PV technologies
under various conditions. Together
with Gebäudeversicherung Bern GVB
we will train installers and users.
This helps to improve solar power
production and avoids fire hazard.
In 2015, flights on special terms are
feasible.
Image 1: BFH’s IR-multicopter drone
The special feature of the system is
the thermography camera that
records a full-radiometric infrared
video at 30 frames per second.
A video instead of a picture
facilitates the evaluation of the data.
Reflections and other irregularities
can be immediately recognized that
way.
The IR camera consists of a
miniature lightweight PC and an IR
sensor. The
used
camera
is
manufactured by OPTRIS, a German
company, and weighs 380 grams.
A Module with a cell fracture and a
faulty soldering – these are the most
frequent defects in PV modules –
was measured and it has a power
loss of about 20% (Image 4).
Power [W]
Image 2 shows the OPTRIS PI400
LightWeight IR-camera system.
Current [A]
PV systems can be quickly and
easily checked for hotspots with
thermal imaging.
However, for large and inaccessible facilities even this technique
is
time-consuming.
Using
a
remote-controlled drone for aerial
thermography the measurement is
flexible and efficient.
Image 3: Damaged solar power system
BFH PVLab sponsored by:
Cell fractures can be seen as bright
spots in image 3. This facility was
victim of vandalism.
▶
▶
Engineering and Information Technology
Photovoltaic Laboratory
Prof. Urs Muntwyler
Jlcoweg 1 | 3400 Burgdorf | Switzerland
www.pvtest.ch | iem.bfh.ch/photovoltaik | [email protected]