Accurate Performance Predictions of Large PV Systems with Shading using Submodule Mismatch Calculation

Abstract

Accurate performance prediction of large PV systems with shading is challenging because computational complexity increases with system size. Solar Farmer is a new PV performance model with 3-D shading. Comparing predictions with measurements from the NIST PV test bed we observed a decrease in the annual difference of 17% between module and submodule shading. By varying the resolution of shading from module to cell level, we also determined that 5 points persubmodule, resulting in a 0.5% annual difference, was sufficient to accurately predict performance of shaded systems. Therefore, a balance of accuracy and computational expense was achieved allowing performance predictions of large PV systems with shade.