PV module measurements

PV modules properties depend on cell type and ambient conditions. To compare modules of different types or from different producers the modules have to be tested under standardized conditions. Usually Standard test conditions (STC) and Nominal operating conditions (NOC) are used.

The electrical properties of PV modules are measured in a laboratory environment or under real test conditions, usually at one of the PV test sites LPVO-A and LPVO-B, which are located on the roof of the faculty building.


Standard test conditions

Nominal operating conditions

  • AM1.5 spectrum
  • irradiance: 1000 W/m2
  • module temperature: 25°C
  • irradiance: 800 W/m2
  • module temperature: NOCT
    • NOCT - Nominal operating cell temperature
    • 800 W/m2, Tair: 20 °C, wind: 1 m/s

Sun simulator measurements

Accurate current-voltage characteristic measurements and determination of STC performance parameters is carried out using flash sun simulator. The simulator ensures constant and repeatable light flashes longer than 100 ms with homogenous intensity of spectrally adjusted irradiance. The simulator meets the A+A+A+ requirements per IEC 60904-9 Ed.3 CD standard proposal.


Spatial characterisation

Prostorska karakterizacija

Since solar cells and photovoltaic modules are large area electronic devices they are prone to various inhomogeneities across their surface. Any inhomogeneity results in reduction of conversion efficiency. Therefore we also perform detailed measurement of spatial conversion efficiency using the electroluminescence technique in various spectral ranges, and additionally with the UV fluorescence technique. Using these methods, we discover most of hidden defects the a PV module that may detrimentally influence temporal stability and energy yield of PV system.


Measurements per IEC 61215 standard

The measurements in our laboratory follow IEC 61215 standard.

IEC 61215/61646 test currently covered in our laboratory:

  • 10.1 Visual inspection
  • 10.2 Maximum power determination
  • 10.3 Insulation test
  • 10.4 Measurement of temperature coefficients
  • 10.5 Measurement of nominal operating cell temperature (NOCT)
  • 10.6 Performance at STC and NOCT
  • 10.7 Performance at low irradiance
  • 10.8 Outdoor exposure test
  • 10.10 UV preconditioning test
  • 10.11 Thermal cycling test
  • 10.12 Humidity-freeze test
  • 10.13 Damp-heat test
  • 10.15 Wet leakage current test
  • 10.18 Bypass diode thermal test


For additional information please contact:

  • Matevž Bokalič, E-mail: Matevz.Bokalic[at]fe.uni-lj.si, Phone: +386 1 4768 276
  • Kristijan Brecl, E-mail: Kristijan.Brecl[at]fe.uni-lj.si, Phone: +386 1 4768 848


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