This thesis aimed to evaluate the performance of the new configuration of the array one of Högskolan Dalarna grid-connected PV system. This PV grid-connected system has been in operation since 1994. The system is composed of two arrays with a rated power of 1.62kW and two inverters of 1.2 kWp. In 2014 the new configuration of array one was composed of 4 strings of 9 modules each. This configuration had twice as much current than array two, and its voltage was halved (180V). The objective was to improve the global performance of the system, mostly under low irradiance conditions. The performance evaluation of the system was conducted according to IEC 61724 standard, and was performed in March and April 2014.
It appeared that the higher current in array one improved the turn-on power of its inverter. While the inverter of array two started operating at 126W/m² the inverter of array one started at 37W/m². It was also shown that the array yield of array one increased by 1% at low irradiance (0-200W/m²) during the two months of this thesis work. Moreover, the input voltage dependency of the inverter was clearly shown. Halved the voltage in array one increased the inverter efficiency between 1% and 2%. It was shown that the higher current of the array one did not impact the losses of the system. The system losses also decreased between 9.4% and 10.5%. Besides, this work highlighted that arrays’ DC power was probably different. It led to a better performance of array two at high irradiance compare to array one. Eventually the performance ratio of array one was greater than array two during these two months. It reached 63.2% in March and 69.4% in April.