Universidad Politécnica de Madrid

Instituto de energía solar

Testing of PV modules and plants


1- Test of PV modules

Two different tests are carried out before the purchase of the PV modules:

Electrical performance and PID

Test of a simple of PV modules to know in detail their electrical response ( STC power, LID degradation and temperature coefficients) and their state of health through electroluminiscences and to determine if the PV modules have a propensity to PID.

Preparation of reference PV modules

Calibration of PV modules to be used as sensors of effective irradiance and operating temperature.



  • STC power and thermal coefficients measurements
  • PID susceptibility test
  • Stabilitation and further calibration of reference PV modules for using as irradiance and module temperature sensors
  • STC power test of already in-field installed PV modules, and comparison with the flash information


  • Measuring I-V curves meanwhile the PV module is heated, from about 20oC to 60oC, inside the “solarBox”
  • PID test: 168 h, 25ºC, conductive foil
  • Preparation of reference modules:
    • Outdoor I-V curve and translation to Standard Test Conditions, as soon as the PV module is received at the IES-UPM facilities
    • Electroluminescence for possible PV module defects detection
    • 25 kWh/m2 minimum Sun exposition, for allowing initial light degradation phenomena.
    • Again, I-V curve, electroluminescence and Sun exposition, until the PV module becomes fully stabilized.

  • In field test:
    • Simultaneous recording of I-V curves (of the tested and of a reference PV module) by means of a twin I-V tracer.
    • Translation to STC
    • Comparison with flash STC power values
    • Thermal analysis
2- Test of PV plants

To characterize the electrical response of a PV plant and to diagnose any possible problem affecting its performance.  


  • Energy production capacity test and comparison with contractual design criteria
  • PV generators STC power and inverter efficiency in-filed testing


Energy production capacity:
Operation conditions recording during, at least, 50 hours of routine operation.

  • Calculation of the corresponding energy production, on the same energy losses scenario than for initial energy yield estimation, and comparison with real energy production as given by the energy counters.
  • PR and PRSTC determination
  • I and V string measurements
  • Thermal analysis of the PV generator.

In field test:

  • Operation conditions and DC and AC power response during, at least, 24 h.
  • STC power determination
  • Inverter efficiency determination
  • Thermal analysis of the PV generator

Contact person: Prof. Eduardo Lorenzo 


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