Multiple MPPT based String Inverter effect on Annual performance: 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 3 MPPT based string inverter are investigated under real different conditions of all season and compared with 4 MPPT based String Inverter with 4-MPPT based System installed at a location with Latitude: 23.290799 N; Longitude: 72.436761E, 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 3-MPPT Inverter system power generation affect between the 0.4 % to 2.8 % compare to 4-MPPT based String inverter Solar PV system. Annual Average Daily Yield, Annual Average Monthly Yield, Annual Average PR and Annual Average CUF for 3-MPPT system and 4-MPPT system are 4.27 kWh/kWp, 132 kWh/kWp, 73.77 % and 19.22 % and.4.35 kWh/kWp, 135 kWh/kWp, 75.16% and 20 % respectively for Solar PV Power System. Due to USE OF 4 MPPT system 31 kWh/kW Energy generation increase compare to 3 MPPT based system which is 2 %.