Smart grid is the new tendency for the Electric Public Utilities. The Smart Grid concept means the total automation for all processes of the EPU. For implement Smart Grid in an EPU are necessary to define enterprise architecture. The enterprise architecture to meet Smart Grid requirements for management systems for EPU in México is presented in this paper. The architecture shows layers of abstraction in the main process: generation, transmission, distribution and energy control and includes automation and control systems at all levels, from plants and substations control systems to corporative intelligent centre, including the operating centre and the energy trading system. Some results and experiences are discussed.