Technical performance evaluation of stand-alone photovoltaic array for outdoor field conditions of New Delhi

In this communication, an attempt has been made to investigate the performance assessment of a solar photovoltaic (PV) array system based on electrical energy output and power conversion efficiency. Simplified mathematical expressions for evaluating performance indices using experimental observations for entire PV array and its individual component subarrays on daily, monthly and annual basis have also been developed. Experiments have been carried out on two individual 1.2 kWp and 1.12 kWp component subarrays of 2.32 kWp stand-alone PV array system for climatic condition of New Delhi (latitude: 28°35′N, longitude: 77°12′E and an altitude of 216 m above mean sea level). Individual performances of both component subarrays were evaluated and its effect on the actual performance of entire PV array has been presented. Numerical computation was carried out for a typical clear day in the month of July 2010. It was found from experimental results that daily power conversion efficiency of entire PV array and its component subarrays1 and 2 were 6.24%, 9.5% and 3.9% respectively. For more effective performance assessment of PV array/subarrays, on field experimental performance results have been compared with the rated (max.) results estimated at STC and also with the maximum performance results estimated for actual climatic conditions as obtained during experimentation.

► We investigate on field technical performance of a solar PV array system.
► We develop simplified mathematical model to evaluate on field performance indices.
► Evaluate daily power conversion efficiency and electrical energy output of PV array.
► Actual PV array/subarray performance has been compared with rated performance.
► Poor performance of one subarray in turn reduces the overall PV array performance.