A combined theoretical and experimental performance analysis of a grid-tied photovoltaic system in semi-arid climate : a case study in Ghardaia, Algeria

Both theoretical study, experimental validation, and outdoor performance assessment of a single grid-connected photovoltaic plant installed on the roof of the car parking located in Renewable Energy Applied Research Unit (URAER), Ghardaia, southern of Algeria have been carried out in this paper. The plant is made up of 16 micro-amorphous modules of 125 Wp and one SMA sunny boy inverter of 3 kW. The results presented were based on experimental data recorded after about three and a half years; from May 18, 2015 to December 31, 2018. The first part of this work, modeling, and validation by the experimental data of photovoltaic array (DC side) based on the Linear Reoriented Coordinates Method (LRCM) and grid-connected inverter (AC side) based on the model developed at Sandia National Laboratories. The results show a good agreement between measured and calculated data (current, voltage, power, and efficiency). The second part of the work is to investigate the operational performance and efficiency of the PV plant from the measured daily power generation and weather as recommended in the International Electro Technical Commission IEC 61724. The performance-computed parameters are based on monthly average daily values, including DC and AC energy generated, reference yield array yield final yield temperature losses PV, inverter and system efficiency, capacity factor performance ratio, and others as defined in IEC. The total output energy PV installation generated during the measured period was of 12944, 44 kWh and the total energy output delivered into URAER internal grid was 12292, 16 kWh. Furthermore, the average daily array yield, final yield, and reference yield varied from a minimum to a maximum value of 2.62 kWh/kWp-6.41 kWh/kWp, 2.51kWh/kWp-6.29kWh/kWp, and 2.39kWh/kWp-6.06kWh/kWp, respectively. In addition, the average daily PV module efficiency, system efficiency, and inverter efficiency varied from a minimum to a maximum value of 8.21-9.00%, 7.56-8.35%, and 94-95%, respectively. The array capture losses, system losses, capacity factor, and performance ratio varied from a minimum to a maximum value of 0.053 kWh/kWp-0.42 kWh/kWp, 0.1206 kWh/kWp-0.31kWh/kWp, 10.30%-26.10%, 79.13%-82.52%, respectively. These results highlight the relatively good performance of PV plants installed in the southern region of Algeria.