The SIUC solar power system consists of 176x BP Solar 3160 photovoltaic (PV) modules, each rated at 160 Watts. The array is divided into 2 subarrays, each consisting of 8 parallel strings of 11 modules in series. At the maximum power point, the array produces 28.16 kW at 386 Volts and 72.8 Amps.
The arrays are ground mounted at a fixed 30 degree tilt angle to maximize annual energy production in our climate and latitude. The DC power output of the array is routed to a single inverter which converts it to AC power at 208 Volts, delta configuration. This AC output from the inverter is routed through a 1:1 dry-type isolation transformer, which converts the power to 208 Volts, wye configuration. Then the power is routed through an AC fused disconnect and connected directly to the SIUC Campus electrical grid.
The inverter monitors the PV array output and the grid power quality continuously and controls the interface between the two. When there is solar power available and the voltage and frequency of the grid are within acceptable limits, the inverter will convert the DC array output into AC power exactly matching the grid frequency and voltage. All this solar power is used immediately on campus as it is produced, reducing the purchases of electricity from AmerenCIPS. The system was commissioned in the summer of 2004 and to date has produced over 60,000 kWh of clean solar energy.