Performance Analysis of a Grid-Tied Solar PV System

Abstract

A grid tied solar PV system can provide energy to the consumers without affecting the climate. Due to minimal maintenance cost and longevity of the inverters and PV panels the grid tied PV system makes itself attractive to the customer. In this work, we have presented the performance analysis of a 200kWp grid-tied photovoltaic (PV) system installed on the rooftop of the Bangladesh Bureau of Statistics Building in Agargaon, Dhaka. Real time output voltage, power, current and energy have been recorded for the month of December 2017. The input solar irradiance is calculated analytically to estimate the system efficiency. All the input and output data were collected and calculated, respectively, based on 1-hour interval. We have observed a maximum and minimum daily energy production of 471.9kWh and 94.5kWh respectively from the PV system. During that observation period, total 9670.5kWh energy is delivered by the PV system. The PV modules of this PV system have maximum 15.4% conversion efficiency and the inverters have maximum 98% inversion efficiency. In that case the maximum theoretical efficiency of the system is 15.1%. Considering clear sky irradiance to the collector without considering the shadowing effect the PV system has 4.94% of monthly average overall efficiency. When we have considered the shadowing effect and clearness index separately, the monthly average overall efficiencies are 5.12% and 7.13% respectively. After considering both the clearness index and shadowing effect the monthly average overall efficiency of the PV system is 7.50%. The PV system has 1.75h/day of average daily final yield and 4.13h/day of average peak sun hours. Capacity factor of this PV system is 6.9% where it should be close to 15%. Average performance ratio is 0.42 during the observation period, however a properly functioning PV system has a performance ratio from 0.6 to 0.8 depending on geographical location and time of the year. Practically it is possible to get a higher system efficiency from this PV system by reducing dirt loss as it exhibits maximum overall efficiency of 10.11% after two days of drizzle. After analyzing the efficiency and other parameters it can be concluded that the system performance is poor. We have found out that the lack of maintenance is one of the main reasons that reduces the efficiency of the PV system. Performance of the PV system can be improved by periodic cleaning of the PV panels and proper monitoring of the inverters and combiner boxes.