Abstract:
In recent years, micro grid system has received more and more attention internationally. As the most effective form of distributed generations, micro grid system has found wide applications in many areas. Micro grids are low voltage (LV) distribution networks comprising various distributed generators (DGs), storage devices, and controllable loads that can operate either interconnected or isolated from the main distribution grid as a controlled entity. This paper describes the operation of a central controller for micro grids. Different control methods of micro grid system and their advantages and shortcomings are carried out and analyzed. The controller aims to optimize the operation of the micro grid during interconnected operation, that is, maximize its value by optimizing the production of the local DGs and power exchanges with the main distribution grid. Two market policies are assumed including demand side bidding options for controllable loads. The developed optimization of a typical LV case study network operating under various market policies and assuming realistic spot market prices and DG bids reflecting realistic operational costs. A laboratory scale micro grid system is proposed as an example to verify the micro grid control strategy. The operation experimental results show that the laboratory scale micro grid system can operate in grid-connected or islanded mode, with a seamless transfer from one mode to the other, and hence increase the reliability of energy supplies.
