Quantitative field performance analysis of a photovoltaic array

Abstract

A quantitative analysis of the long-term field performance of a photovoltaic (PV) array has been made considering such field variables as solar insolation, temperature and long-term degradation of a solar cell. It deals with (i) the numerical analysis of two degradation factors of a single crystal solar cell, namely, increased lumped series resistance R_s and decreased short circuit current I_sc (ii) the field condition V_m - I_m relation, and (iii) the ratio of I_m and I_sc for a PV array. The value of Im has been computed from the solution of a transcendental equation using Newton-Raphson approximation technique. This approach has been verified by field data obtained in Delhi, India, over a period of four years for the single crystal silicon PV modules (manufactured by CEL, India). It can be used for the study of the long-term field performance of a polycrystalline and amorphous silicon PV module.