EMS of hybrid AC/DC micro grid
Date of Issue2016-08-22
School of Electrical and Electronic Engineering
As modern techniques for power system utility have grown more mature and developed, traditional power systems are no longer the best electricity market for both the consumers and suppliers. The issues coming along with traditional power system can be terrible for the environments, such as large use of fossil fuels, coal; long distance of transmission lines also will cause the cost of money and fuels for the electricity transmission process. Besides these, the emergence of renewable energy resources has changed the way of generating electricity from the very beginning. Large application of renewable resources like solar energy, wind power, energy storage systems has been widely utilized. The fast development of renewable resources draws much attention to the dc grid, because most electricity comes from renewables is dc. So with more and more dc electric loads, existing power grids can no longer provide the best power quality for the consumers, and the conversion stages between ac and dc will lead to the cost which is not the situation suppliers want to have. Under the need for reducing the cost of the whole process and the push of new emerging techniques, hybrid ac/dc micro grid system is brought up by researchers. Hybrid ac/dc micro grid is a power grid which has energy supply from both ac and dc side, with diesel generators, all kinds of renewable energy resources. In this way, the cost for transmission and conversion stages can be reduced so that the price of electricity can be controlled. In hybrid ac/dc micro grids, all the generation units including those mentioned above will be coordinated together to achieve best performance with least cost. In order to minimize the cost and improve efficiency, energy management system is used for load forecasting, unit commitment, economic dispatch and so on. By implementing these methods, the most economical way can be calculated. In this paper, we will focus on the load forecasting process which is very essential for energy management system. Accurate and reliable forecast models allow electric utilities to make timely decisions and carry out effective manipulations. This thesis proposes three STLF methods which are respectively ANN, SVM, and DTs. The simulation results are presented.
DRNTU::Engineering::Electrical and electronic engineering