This book describes the fundamental aspects of the new generation of electrical distribution grids, taking as its starting point the opportunities that exist for restructuring existing infrastructure. It emphasizes the incorporation of renewable energy sources into the distribution grid and the need for a technological evolution towards the implementation of smartgrids. The book is organized into two parts: the first part analyzes the integration of distributed energy sources into the distribution grid and the impact of these sources on grid operation. After a general description of the general characteristics of distribution grids and renewable energy sources, it then analyzes the economics of electrical energy distribution networks and presents the impact of these sources on grid operation. The second part of the book then analyzes the various functions which allow for safe operation of the grid and realization of the path towards real world application of smartgrids.