CRITERIA FOR THE INSTALLATION OF SECONDARY SUBSTATION CIRCUIT BREAKERS, PROTECTION SYSTEM SET-UP AND OPERATION OF THE NETWORKS WHEREIN THEY HAVE BEEN INSTALLED

The paper describes the use of circuit breakers along MV feeders to select quickly the part affected by short circuit and improve the continuity of supply on distribution network. The document is organized in two parts: the first one deals with the HV/MV transformer, MV feeder and secondary substation circuit breakers protection systems coordination. The second part of the paper considers the first operation data results. We took into account 2008, 2009 and 2010 interruptions data recorded by Enel Distribuzione SCADA system and in particular the number of interruptions on MV feeders before and after secondary substation circuit breakers installation.