Optimal power flow in microgrids with renewable energy sources considering congestion

Microgrids are small power systems with diverse distributed generators with high reliability. With recent developments in the area of renewable energies and increasing concerns about environmental issues, microgrids are rising as excellent candidate to address multiple issues with current power grids and at the same time they can decrease the total cost of electricity. Because of their unique characteristics, design and operation of microgrids are different than conventional power systems. In this thesis a comprehensive method to optimize the operation management of a microgrid is presented. Various factors including fuel cost, environmental cost, maintenance cost, start-up and shut-down costs, spot price of electricity as well as the effect of congestion and ramp rate are considered. In this regard, the sum of different costs of microgrid operation is considered as an objective function. Four different scenarios are investigated to see the effect of low and high penetration level of wind unit, spot price of electricity and environmental cost on the operation of a microgrid. To demonstrate the performance of the presented method, a test system consisting of microturbine, fuel cells and wind unit is considered. Simulations are carried out using MATLAB and results of the optimal operation management are presented in each case.