PV Analyzer I-V Curve Tracers

* High efficiency modules have high capacitance which can cause a large in-rush current when I-V curves are measured. The PVA is designed to tolerate a certain level of in-rush current. But if it is large enough, it can trigger an over-current warning in the PVA-1000 and PVA-1500V4/T that prevents the measurement from completing. For this reason, it is recommended that strings of modules with efficiencies ≥ 19% be limited to less than 10A (or else be measured with the PVA-1500HE). The in-rush current is increased by higher efficiency, higher current strings, higher voltage strings, higher bifaciality, and higher irradiance. For example, a 1350V string of bifacial 21% efficiency modules with Isc of 18A at irradiance around 1000W/m2 will likely cause the over-current warning. Lower string voltages can allow currents higher than 10A, even with high efficiency modules, so breaking-up strings to reduce voltage and adjusting tracker orientation for lower irradiance can be an I-V measurement solution in most cases. The PVA-1500HE is designed to accommodate strings up to 30A even with module efficiencies ≥19%. For more information on high efficiency modules, see the Solmetric app note I-V Curve Tracing of High Efficiency PV Modules

** Assumes reference PV system with Voc = 1300V, Vmp = 1100V, Imp = 25A, 16 strings per combiner, 5min to move to next combiner with no measurements. No direct sunlight on I-V unit.