Evaluation of a large PV installation inFalun

Abstract: The study summarizes the performance of a large PV system, a 150 kWp plant, during 14th February and 16th April in Falun, Sweden. It has been in operation since the end of January 2008. It feed the generated energy into the grid and is used by the building. The system consists of 4 photovoltaic arrays 861 modules of 175 Wp with 26 inverters which are connected to each string array. The strings array configuration has 7 different configurations. The 4 main arrays are installed on the roof of the building in two orientations. The performance parameters are calculated as defined in IEC 61724 and daily and monthly energy balance are investigated. The possible shading is also studied and the measured radiation is reviewed relative to the power production. A radiation measured by sensor 1 is revised as there is substantial differences are detected. This is corrected by a correlation developed with measured DC power production normalized to the module verses measured irradiance. A same system is modelled in the PVSyst program to simulate for the expected energy production and performance parameters which are then compared with the measured results on an emphasis on the module temperature as the module has a black tedlar coating. A performance evaluator in Excel is also created following the same procedure as the evaluation is done. It can be used to evaluate the performance of the system in the future. The system generated about 16.8 MWh. The average electricity generated per day is 266 kWh. It ranges from 30 kWh/day in February to 662 kWh/day in April. The final yield Yf ranged from 0.2 to 3.4 h/day and the performance ratio PR range from 0.35 to 0.98.