Unintentional Islanding in Distribution Networks with Large Penetration of Power Electronics and Renewable Energy Systems

The PhD thesis focus on the analysis and investigation of a crucial issue related to increasing number of distributed energy resources (DERs). This recent issue is the unintentional (i.e. uncontrolled) islanding operation in distribution network with large penetration of DERs based on power electronic converters. Particular focus has been addressed to the interaction between DERs, protection systems and new connection rules required by standard bodies. The aim of the research activity is the investigation on the causes and the influencing factors of unintentional islanding in medium and low voltage (MV and LV) distribution network. The unintentional islanding issue has interested many studies and publications over the last decades. However, the literature research is lacking of considering the lately introduced European standards and technical specifications for DERs. Therefore, during the PhD research, novel aspects of how requirements and ancillary services influence the unintentional islanding operations have been studied, highlighting novel relevant factors, such as the role of the loads characteristics, the influence of the frequency measure and the inverter regulation speed.

The PhD thesis focus on the analysis and investigation of a crucial issue related to increasing number of distributed energy resources (DERs). This recent issue is the unintentional (i.e. uncontrolled) islanding operation in distribution network with large penetration of DERs based on power electronic converters. Particular focus has been addressed to the interaction between DERs, protection systems and new connection rules required by standard bodies. The aim of the research activity is the investigation on the causes and the influencing factors of unintentional islanding in medium and low voltage (MV and LV) distribution network.