Computer relaying for smart grid protection

In order to improve reliability and availability in upcoming smart grids, a number of effective actions based on new digital protection systems are suggested. The functions of new generation digital protections are presented and discussed, and operating solutions in designing smart grid protection plans are illustrated. As a matter of fact, smart grids are crucial, complex systems that must ensure a very high quality of the electric power delivered. In order to increase the distribution system reliability, also protection backup systems are identified and discussed. The main digital functions investigated are overcurrent code, directional overcurrent code and undervoltage code. Considerations on the selectivity plan and apparatus setting are also made. Finally, comments and suggestions are reported about the reconfiguration and restoration of the power system after a fault clearance.