Analyses and monitoring of photovoltaic systems

Although photovoltaic installations are built to be long lasting, the system power specified by the manufacturer is not always the same as that effectively generated. These differences in performance can result from manufacturing defects, damage, design errors, the impact of bad weather and climatic conditions, and other unintentional factors.

For final users, however, it is not easy to identify the cause of these system performance differences, because their knowhow and means are limited, and they cannot obtain accurate inverter performance measurements.

For this purpose the photovoltaic systems Quality team offers a detailed measurement service that can identify and/or confirm any malfunctions, also providing analysis tools for preventive system maintenance operations. The analysis activities conducted by the Group include:

  • characteristic I-V measurement of the PV field and extrapolation to STC (Standard Test Condition)
  • detailed visual inspection of the photovoltaic installation 
  • thermographic analysis
  • measurement of the instantaneous yield of the system 
  • general check of the PV systems

It should also be borne in mind that energy production varies over the course of the year, also in accordance with the module typology and the assembly configuration utilised. PV system operation analysis can be conducted correctly only by means of an analytical control conducted utilising a precision data logger (DL) and measuring the irradiance by means of pyranometers and calibrated reference cells. Panel temperatures should also be kept under observation, and, in this case, precision RTD can be utilised. The ISAAC solar energy team offers a medium-long term analytical measuring service for autonomous, grid-connected photovoltaic systems.

The parameters analysed include:

  • Final Yield calculation (Yf): Final Yield [kWh/kW]
  • Performance Ratio calculation (PR): Performance Ratio [-]
  • low irradiance performance analysis
  • any electricity losses recorded by the system

PV system reconditioning

The lifespan of a photovoltaic system is usually calculated based on the lifespan of its modules. However, the most delicate element of a grid-connected system is not the module itself, but the electronic and power parts, together with the excess voltage protection elements.

Halfway through the lifespan of a system it is often necessary to replace the inverter, carry out refurbishment work, or modify various electronic parts. 

The Institute for Applied sustainability to the built environment also offers consulting services for reconditioning photovoltaic systems. Analyses conducted can specify the optimal reconfiguration of the installation, and all the maintenance operations to carry out in order to ensure that the system has a lasting and effective lifespan.