Optimal Configuration and Sensitivity Analysis of Distributed Generations in a Grid-connected Micro-grid

In this paper a grid-connected micro-grid system is established and simulated in an attempt to find out the optimal configuration of distributed generations (DGs) in the system. A typical micro-grid structure comprising of wind generator, photovoltaic array, micro gas turbine and storage battery is presented; and the output model of DGs is built. The proposed grid-connected micro-grid with thermal load is developed in hybrid optimization models for energy resources (HOMER) software. Emission penalties of the micro-grid, cost parameters of all DGs and fuel consumption are addressed in the HOMER software. The simulation result shows that the total net present cost (NPC) of the case under study reaches its minimum when the photovoltaic capacitor is 500kW, the wind capacity is 1000kW, the micro gas turbine capacity is 500kW, the inverter is 500kW and the purchased power is 200kW. It will be shown that the optimal configuration of DGs is meeting the demand of the loads in this system. A sensitivity analysis of the natural gas price and the electricity price is studied to find out the impacts of various parameters to the micro-grid system, and the results show that in this case the natural gas price fluctuation has the most pronounced effects on NPC.