The document discusses various factors leading to reduced power output in photovoltaic systems, including installation errors, shading, and mismatched components. It outlines procedures for diagnosing issues, such as checking string voltages and AC outlets, and emphasizes the importance of proper installation and regular maintenance to optimize performance. Additionally, it highlights techniques for testing and mitigating power loss caused by stray currents and other operational faults.

1. PV Installations & Errors
Prevent Errors upfront
Andreas Iliou / Suntech
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2. Photovoltaic Systems
Energy Audits
Protection
Maximum Power Point Tracking (MPPT)
Weak light – Shading
Microcracks Production,
during Transport and Installation
Photovoltaic Systems
Energy Audits
Protection
Backfeed Current
Leakage Current
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3. 01
Photovoltaic Systems
Energy Audits
Protection
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4. Reason for less power output
 Power Plant with less kWh/kWp compared
with nearby installations
 Planning layout / Optimization
 Mismatch losses due to wrong inverter / module
combination (high losses ) resize cable diameters
 Strings not correctly installed,single modules not
Connected polarity wise – connectors without contact
 Mismatch losses can be changed regards inverter
e.g Multistring inverter agains 1 Tracker
 Shading not upfront recognised, restring or
reinstallation of different invertertype
Cleaning of inverters regularly (heat transfer /cooling!)
to hot surface temperature at cooling and/or AC side
testing procedureI-V curve testing
All Rights Reserved Source Iliou

5. Reason for less power output
 Power Plant with less kWh/kWp compared
with nearby installations
 Planninglayout/Optimizing
 Distance of inverters to close by
 Inverter cools down from right to left therefore
heating up uneccessarily second and third inverter
 Losses due to planning and/ or installation
mistakes accumulates up to 250 W losses
 Systems runs without ( Datalogger )
no stringcontrol,
 Inverter covered and overheats , built in a small room
no cooling possible,
cuts off frequently without problems
Iso faults, shortcuts etc.
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6. Reason for less power output
Inverters must be installed according manual
Source Mastervolt
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7. Reason for less power output
Alternative Solution: Board can be used to split incoming Air
All Rights Reserved Source Mastervolt

8. Reason for less power output
Different topologies involved
All Rights Reserved Source google

9. Reason for less power output
Shaded or already to less modules planned
All Rights Reserved Source Iliou

10. Reason for less power output
Shaded or already to less modules planned
All Rights Reserved Source Iliou

11. Optimising Power output
Optimum East- / Westconfiguration: 2:1 = 2 Strings right and 1 String left
3:1 = 3 Strings right and 1 String left
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12. Tests to determine less power output
Shaded or already to less modules planned
 Check of all AC outlets
 Check of all earth wires
 Polaritytest of each string
 Testing of all Stringvoltages
 Measurements of shortcut current
 Isotest of all DC strings
 Performance test and visual inspection
of all components
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13. Tests to determine less power output
Check poweroutput with the Voltage AC grid
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14. Testing procedure – less power output
Shaded or already to less modules planned
• Visual Inspection Check of all AC outlets
• Isolationtest
• Check of all deactivation figures
• Cable size and resistance check
• Values should be underneath <1 Ohm
• Feed in AC checked with AC site
All Rights Reserved Source Iliou

15. Testing procedure – less power output
Shaded or already to less modules planned
• Are modules covered with grease or dust ->
please check
• Contacts faulty , check each single string
• Bushes or trees grown up
Is it possible to increase or still decrease MPPT
from the inverter or are to less modules connected
when Shading occures with more than 1 single
module
Involved.
Temperature zone concept been used
Are more systems already been built in the
neighbourhood
All Rights Reserved Source Iliou

16. Testing procedure – less power output
No power output during daytime
Shaded or already to less modules planned
Meter doesn t turn
Still to dark outside, check later on again
 Circuit breaker turned down ?
 Switch defect ?
 Lightning protection device faulty? ->current flowing
 During winter everything worked fine , ½ year later
extremely poor output achieved
always during high peak and high temp->low output
 Power failure Main Grid
 Iso fault with no reason, check contacts involved
 Single test of each string
 Data locked at inverter -> please check
 Failure in AC Supply , please check with earth loop tester
All Rights Reserved Source Iliou

17. Less power output due to stray currents
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18. Less power output due to stray currents
All Rights Reserved Source EP

19. Less power output
cause is stray , and ground currents
PE+Neutral bound together- lot s of stray currents ,more losses
All Rights Reserved Source EP

20. Less power output
cause is stray , and ground currents
PE+Neutral seperate - NO currents ,less losses involved
All Rights Reserved Source EP

21. Thank you 1
Andreas Iliou
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