A nominal 5 kW mono-crystalline silicon photovoltaic array is to be grid connected via an isolated inverter located 10 m from the array. The array is composed of 60 modules where each photovoltaic module has a rating at STC of: . Power = 85 W Voc = 22 V Isc = 5 A Vmp = 18 V Imp = 4.72 A 1(maximum overcurrent protection) = 14 A The normal range of operating conditions at the site will mean a range of open circuit voltages (Voc) from 18.76 V to 23.74 V is expected and a range of Vmp voltages between 15.35 V and 19.44 V is expected. The inverter is rated at 4.8 kW continuous at 50 C with the voltage and current ratings shown below: Vmax = 285 V with a maximum power point tracking range of 130 V to 255 V Ilimit = 29 A (current limited), Imax connected array = 40 A. The array has some shading that occurs in winter on the right-hand side column of modules of the array late in the afternoon as shown on the figure 1 (below). A central array junction box is available as shown in the diagram and a main photovoltaic cable is used to connect this main junction box to the inverter. (i) (ii) How many strings and how many modules per string would you select and why? Sketch the wiring configuration for one string of the array, using figure 1 as a template. The wiring should be arranged to minimize losses of cable to junction box and take into account shading of the array. O O O O O O O O O O 0 O O O o o O O o o O O O O O O 0 O O O 0 O O 0 0 O 0 o 0 O o o O o O O O o o O O O o O o O o O O O O o O O O O O O O O 0 o o 0 o O O O O O O o ollo O Shaded PV Double pole break switch Double Inverter pole break Pv array junction box switch Pyarray cable Figure 1: PV array grid system A nominal 5 kW mono-crystalline silicon photovoltaic array is to be grid connected via an isolated inverter located 10 m from the array. The array is composed of 60 modules where each photovoltaic module has a rating at STC of: . Power = 85 W Voc = 22 V Isc = 5 A Vmp = 18 V Imp = 4.72 A 1(maximum overcurrent protection) = 14 A The normal range of operating conditions at the site will mean a range of open circuit voltages (Voc) from 18.76 V to 23.74 V is expected and a range of Vmp voltages between 15.35 V and 19.44 V is expected. The inverter is rated at 4.8 kW continuous at 50 C with the voltage and current ratings shown below: Vmax = 285 V with a maximum power point tracking range of 130 V to 255 V Ilimit = 29 A (current limited), Imax connected array = 40 A. The array has some shading that occurs in winter on the right-hand side column of modules of the array late in the afternoon as shown on the figure 1 (below). A central array junction box is available as shown in the diagram and a main photovoltaic cable is used to connect this main junction box to the inverter. (i) (ii) How many strings and how many modules per string would you select and why? Sketch the wiring configuration for one string of the array, using figure 1 as a template. The wiring should be arranged to minimize losses of cable to junction box and take into account shading of the array. O O O O O O O O O O 0 O O O o o O O o o O O O O O O 0 O O O 0 O O 0 0 O 0 o 0 O o o O o O O O o o O O O o O o O o O O O O o O O O O O O O O 0 o o 0 o O O O O O O o ollo O Shaded PV Double pole break switch Double Inverter pole break Pv array junction box switch Pyarray cable Figure 1: PV array grid system