Design of Grid Connected Rooftop Solar PV System (Case Study: Dire Dawa Industry Zone)

Abstract

Dire Dawa is one of the industry center in Ethiopia. Due to expansion of industry in Dire Dawa and around the city electric demand is increasing. Distribution Generation have advan tage over central generation by minimizing transmission line loss. Solar photo-voltaic(PV) system is becoming a promising energy sources because of its advantages. But the solar in stallation need large area to install the panel and other components which, is not available near load center because of its cost. When looking for land far from the load center it costs transmission line and line losses which is unwanted. Dire Dawa industry zone have many industries in it. Each factories have big buildings with large roof area which can used to install solar PV system. The other problem is when grid is connected with solar PV system it should be in the standard. The purpose of this research is to design a grid connected roof top solar PV system for Dire Dawa industry zone. To address the objective, data gathering were done in Dire Dawa industry zone and by using the collected data the grid connected solar PV system were designed in PVsyst software. Secondly, the research was focused on designing the component of grid connected rooftop PV system, such as solar PV, DC-DC converter, NPC inverter, filter and their controllers. Finally, the signal analysis were done by Matlab/Simulink. In addition to that, the rooftop mounted and ground mounted PV system were compared by the investment cost and transmission line cost. The result shows, the performance ratio is 84.2% and the total investment cost for Dire Dawa industry zone is 320 million ETB to generate 8545 KW peak power generated on the rooftop of the site by the levelized cost of energy(LCOE) it become 0.99 ET B KWh for this design. The simulation result of Matlab/Simulink also shows that the inverter output active power follows the trend of PV DC power, which depend on the value of solar irradiance and temperature values. When it come to the reactive power it is not dependent on irradiance and temperature value, so the value of inverter reactive power can control at any desired value and at any time of day or night. The harmonic analysis also done and the quality of the grid is not disturbed. When there were a power interruption, the stand-alone solar PV system take the load and supply it. The comparative study shows rooftop solar PV system have more advantage than ground mounted solar PV system by transmission line loss and installation cost reduction in case of Dire Dawa industry zone.