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 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) O O O O O limit= 29 A (current limited), Imax connected array = 40 A. O O O O 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 O O O O O O O O O O 0 Pv array junction box O O O O O O O O O O O Double pole break switch O O O O O O O O O O O O O O O O O O O O O O O Double pole break switch O O O O O O O O O O O O O O Py array cable Figure 1: PV array grid system O O O O O O O O Inverter O O O O O O O O O OOO O O O O O O O O O O O O Shaded PV