Examples and References
Photovoltaic Experts
Jendra Power AG
Example project

Example Project „Technical DD“ of a Solar Power Plant in South Italy



mandate: Check the power plant on technical conformity, design, maintenance status and performance.


Main figures of the power plant:



Photovoltaic Installation





nominal powerDC


999 kW


nominal power AC


979 kW






Module supplier


Renewable Energy Corporation REC




160 REC 240 PE / 3'920 REC 245 PE


power per module


240 - 245 W


number of modules







inverter supplier






Refusol 20 K


power per inverter


 19.2 kWAC
19.6 kWDC


number of inverters








producer of structure


H. Kühling Stahl- und Metallbau GmbH


  • check of inverter dimension
  • check of cable dimension
  •  check of the design of the power plant (like stringing, shading angle, inverter dimension etc.)
  • analyze of the security system
  • check of the structural stability
  • check of the production


Ill. 1: view of the structure


executed on site works    

  • visual check of all components
  • check of the installation quality
  • check of the modules
  • check of the string currents
U-I-curve measurement on a selected number of strings

results of the analyze


The power plant has been assessed to be good, with some minor reserves


Check of the modules

The U-I-curve-analyze has shown a good result for the solar modules


ill. 2: sample of IV-curve measurement



The measured power on site was just 5% below nominal power. This result can be considered as being good, the curves had a good shape.

The main weak point of this installation was DC cabling below the modules. We made haere a reserve ans asked for improvements.

ill. 3: insufficient cabling 



ill. 4: inverters


The only reserve for the inverters was the exposition of the displays towards sun. The displays were subsequently covered by plastic sheets. We have also registered the regular failure of inverters without being able to find the reason.


The security system has been assessed as being too weak (addendum: unfortunately confirmed through a modul theft two years later).


ill. 5: camera pole

Unfortunately, our assessment of the security saytem has been approved by a theft of solar modules.

Analyze of the production

The available data have been carefully analyzed







ill. 6: comparison of the inverters



  •         The high shading angle is visible in the reduced production of the lower row during winter time.

  • Fuse failures become visible (4 strings, 1 fuse = 25%)


ill. 7: monthly performance

Forecasted yield of production : 145‘000 kWh/a


Registered yield (normalized on a average year): 150‘000 kWh/a


The power plant is productin better than expected.

We gave the advice to the investor to purchase the power plant, but requested some minor improvments.





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