Annual performance of Multiple MPPT based String Inverter under Partial Shadowing: Observations at Utility scale Solar PV Plants

PV industry continues to search for opportunities to reduce the losses associated with site condition and designing of the system. String inverters can capture performance in more detail with multiple MPPT configuration; this may lead to improved performance for sites with irregular terrain and additional plant diagnostic capability. In this paper, the power losses in long string of 20 nos. series-connected 320 Wp PV modules and three strings of six series-connected PV modules connected in parallel to the 33 kW string inverter are investigated under real different partial shading conditions of all season and compared with similar with non shaded system installed at Latitude: 23.290799; Longitude: 72.436761, to determine their comparative performance characteristics in real, outdoor conditions. We interpret our observations with practical analysis based on the results of field measurement. Base on the research we can say that in partial shadow condition the power output affect between the 2 % to 18 % in 3 MPPT based String inverter Solar PV system. Annual Average Daily Yield, Annual Average Monthly Yield, Annual Average PR and Annual Average CUF for partial shading system and non shaded system are 4.1 kWh/kWp, 128 kWh/kWp, 71.3 % and 19.26 % and.4.3 kWh/kWp, 132 kWh/kWp, 73.4% and 19.91 % respectively for Solar PV Power System. Due to partial shadow 45 kWh/kW Energy loss compare to ideal system which is 3 %.