Soiling and Irradiance Measurement Systems with the RDE300 Series measurement and control unit collect critical  data  for evaluating PV array performance.  

The  systems can be used at operating PV power plants and pre-construction site survey locations.

Each system uses one or two attached PV reference devices to perform measurements. 

Major applications include:

  • Irradiance Measurement: Using a calibrated PV reference cell or reference module, the system  produces  accurate  irradiance  measurements  that  are  well  matched  with  the  effective irradiance perceived by the user’s PV array. Optional automated washing of the calibrated  PV  device  ensures  that the  irradiance  measurements  are  free  of soiling  artifacts.
  • Soiling  Measurement:  Using  a  pair  of  PV  devices,  one  clean  and  the  other  naturally soiled,  the  system measures  power  loss  due  to  soiling.  The  system  allows  the  user  to  choose a PV module identical to those in their PV array as their soiled reference module, ensuring that soiling measured by the system accurately represents soiling on the user’s PV array. Optional automated washing of the clean reference device minimizes technician labor.

Accurate and reliable measurements are ensured by advanced features, including:

  • I-V  Curve  Measurement:  The system  measures  both  short-circuit  current  and  output  power of PV modules from a complete I-V curve, ensuring accurate results even when soiling is spatially non-uniform. 
  • Choice  of  Hold  State:  In  between  measurements,  the system  holds  PV reference modules at the user’s choice of either open-circuit (typical for crystalline silicon modules) or short-circuit (typical for thin-film modules), minimizing PV module degradation.
  • Advanced Wash Unit: The optional automated wash units not only provide an effective way  to  ensure  clean  irradiance  measurements  without  technician  labor,  but  also  have advanced features for reliable operation, including: 
  • Built-In Analysis: The RDE’s internal software analyzes all readings performed each day and produces filtered daily average values available on separate registers, reducing the need for post-processing of the data on the user’s logging platform.

For more information, see RDE300 Series User Guide.