Post on 18-Apr-2022
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1 Solarzentrum Stuttgart GmbH,
Rotebühlstr. 145; 70179 Stuttgart, Germany
Luminescence Imaging of PV Modules in Daylight
DaySy
Liviu Stoicescu and Michael Reuter
info@solarzentrum-stuttgart.com
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What has your PV system been through?
… looks fine does it not?
dropped module
PID
bypass diode failure
hail
broken busbar
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Outline
Why electroluminescence?
The DaySy method.
Real live examples
Measurement throughput
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Why Electroluminescence …?
Hail: 80% severely damaged modules
Not detectable in thermographic imaging
Not detectable in the output power (yet)
Electroluminescence imaging detects
- Present challanges
- Future points of failure
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DaySy vs. THE HAIL
No hotspots detected
Electroluminescence images show defects and hail impact
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The DaySy Method
Electro (EL) - and photoluminescence (PL) characterization
In full daylight Independent of surrounding light
On mounted modules and full strings
Using either the PV-plant or a DC source as power supply
From an overview to detail images!
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DaySy –EL (self-powered)
DaySy EL
DaySy Box
2 - 6 Generator-Strings
Psun > 200 W/m2
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DaySy –EL (DC powered)
DaySy EL
DaySy Box
10 kW DC power supply =
The 10 kW DC power supply enables 24h around the clock operation
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Handling
Add more cameras for higher throughput
Self powered from PV field
Cam 1
Cam 2
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Availability of outdoor imaging methods
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Whole string imaging
live live
daysy daysy
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Real live: 'Angry birds'
Damage detected in Japan near golf course at coastline
- birds drop golf balls, mussels, nuts etc.
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Real live: Do NOT "Kärcher" your PV !
Severe damage due to high-
pressure cleaning from back…
https://www.kaercher.com/de/inside-kaercher/sponsoring.html
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Real live: Do NOT drop PV modules
ONE broken module will kill the performance of
your complete string (until bypass diodes will
take effect).
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Broken bypass diodes - very common!
easily detected by DaySy, if in short-circuit
not so easy in I/V
almost no chance, if in open-circuit
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Real live: Polarization of strings (PID)
Polarization of Sunpower modules towards
high-voltage end of string.
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Real live: PID
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Real live: mono c-Si Modules
micro-cracks
broken fingers
potential induced degradation (PID)
damaged cells and cell areas
groups of broken fingers
groups of broken
fingers
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Image captured from riser lift
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Image captured from riser lift
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Real live: Hail on mono c-Si Modules
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Image captured from riser lift
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Image captured from riser lift
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Image captured from riser lift
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Image captured from riser lift
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Image captured from riser lift
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Image captured from riser lift
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Image captured from riser lift
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Image captured from riser lift
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Image captured from riser lift
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EFG Modules
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EFG Modules
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Real live: Hail on multi c-Si Modules
[320 cam]
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Hail on multi c-Si Modules
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Hail on multi c-Si Modules
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Hail on multi c-Si Modules
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Hail on multi c-Si Modules
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Hail on multi c-Si Modules
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Estimated Throughput in 24 h
Inverter
Cluster
Scenario
Field PV installation, 250Wp modules, 20 modules/string
Location of PV strings is known (good documentation) 10 min / string / operator
1 minute for a EL image; 2 minutes for a EL+PL image
2 Operators
Micro-
Cracks
Cracks
Single Fingers
Potential Induced Degradation (PID)
Broken Cells, Damaged Areas
Finger Clusters
Imag
ed
kW
p i
n 2
4h
900
750
600
450
300
150
0
1200
1050
PID
Bypass diode
Micro-cracks
Broken cells
cracks
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Throughput on Hail Crack Detection
Shaky Lift or Low Voc
12 Modules / h
Stable Lift
16 Modules / h
Rooftop
30 Modules / h
High Voc
60 Modules / h
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Real Throughput in 24 h (one camera)
Micro-
Cracks
Single Fingers
Potential Induced Degradation (PID)
Broken Cells
Finger Clusters
900
750
600
450
300
150
0
1200
1050
Imag
ed
kW
p i
n 2
4h
8000 Modules – 2000 kWp PID
High Voc
Rooftop
Shaky Lift
Hail Damage
Increase throughput
- Use two cameras
- Use high resolution camera
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640x512 320x256
Camera resolution results with one image per module
640x512 320x256
Same images but
cropped to quarter
module
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Thin Film: Some impressions…
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CIS
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CIS
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CIS
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CIS
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Photoluminescence
on module level
EL PL Defects
Series Rs ++ - - Broken Fingers
Shunt Rp - - + + PID, Low Light, Shunts
Shunts from Hail Impact
PID
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Outlook
Thank You for Your Attention