Dispersed generation in MV networks: Performance of anti-islanding protections

The growing development of Dispersed Generation drives to a novel management of distribution networks in order to take advantages of this new form of generation. In particular the DG determines different power flows along distribution feeders modifying voltage profiles and fault levels and introducing new issues in protection systems. This paper addresses the issues of islanding of a portion of the medium voltage system in different operating conditions. The aim is to evaluate the most used passive methods performances, in particular with respect to the Italian anti-islanding protection systems. On the basis of the results new schemes will be proposed to reduce anti-islanding protection bad operation.