Effect of the diffuse solar radiation on photovoltaic inverter output

Abstract

Solar global irradiance received at a horizontal level on the earth varies significantly over short intervals due to diffuse radiation changes. Experimental data on global irradiance profiles received by fast data recording systems show that the global irradiance may be enhanced for a few minute periods by as much as 40%. The diffuse radiation is intensified by dry air mass formations, airborne nanoparticles, and cloud formations at higher atmospheric levels. Evaluation factors for photovoltaic system design (i.e. sun hours, tilt angle, module direction, soiling, module reflection, and losses due to temperature, wiring and module output differences) may also have to consider possible global irradiance surges. Power monitoring of a photovoltaic park has shown that the delivered AC output power by the inverters can be increased beyond their nominal limits due to diffuse radiation effects, thus rising component reliability issues. © 2010 IEEE.