Adaptive Network Protection in MIcrogrids

Abstract

Microgrids comprise low voltage distribution systems with distributed energy re-sources (DER) and controllable loads which can operate connected to the medium voltage grid or islanded in a controlled coordinated way. This concept aims to move from " connect and forget " philosophy towards an integration of DER. Mi-crogrids are expected to provide environmental and economic benefits for end-customers, utilities and society. However, their implementation poses great techni-cal challenges, such as a protection of microgrid. Local generation in a combina-tion with a possible islanded operation can pose protection sensitivity and selectiv-ity problems in case of fault depending on the relay settings. This paper presents a novel adaptive microgrid protection system using digital relaying and advanced communication. The protection system is based on a cen-tralized architecture where relay protection settings are modified centrally with regard to a microgrid operating condition.