How Useful is a Field-Operable I-V Curve Tracer?

Solar power is continuing its upward trend of megawatts installed per year across the board in the residential, commercial, and utility sectors. To assess the performance of PV modules onsite, field-capable I-V curve tracers have proven to be an essential tool in identifying and troubleshooting PV performance issues. Coupled with solar irradiance meters, surface temperature probes, and a PV module database, field-operable I-V curve tracers can calculate whether a particular PV module, or string of modules, is performing to manufacturer specifications. The key parameter that technicians typically want to know is the maximum power output of the PV system. However, the electrical, irradiance, and temperature measurements have measurement uncertainty associated with them, as well as technical issues that limit how accurate they can be for a given PV setup. This work looks at several different I-V curve tracers, including the Fluke SMFT-1000, to understand the differences between different technologies and how accurate an I-V curve tracer can actually be when measuring the maximum power output of different PV systems.