New trends in electricity production, that involve generating power locally at the distribution voltage level by using renewable energy sources, are changing the paradigm of the distribution network, giving it an active role with the integration of Distributed Generators (DG), which leads to the concept of active distribution networks. A key element that connects the distribution system to the rest of the power system is the medium to low voltage transformer substation, which requires further research and development in order to develop active distribution networks. This document presents an overview about the components and functions that an intelligent substation automation system may have.