This paper proposes an automation system logic for distribution networks (DNs) with the aims of improving reliability indices through the implementation of selective fault detection, fast network reconfiguration ad automatic back-feeding. A hierarchical approach of smart substations is presented base on IEC 61850 standard, electronic instruments, optical fiber communication network, etc. The protection and control system includes three main blocks: primary substation protection, secondary substation protection and the logic selectivity. These three blocks contribute to create the smart automation system which can improve protection performance, in order to transform the majority of the faults to transitory interruptions lasting less than one second, and control capability of the system. The main issues and challenges of the automation system logic are presented with a detailed description of primary and secondary substations protection system and relays as well as the logic selectivity. Moreover, a case study on a real DN is reported to demonstrate the effectiveness of the proposed approach.

distribution system,system reliability,protection system,Substation Automation; CAN bus; Network Controller; Communication Protocol