An Overview of Issues Relevant to Protection and Restoration of PV Systems at Distribution Level

This paper discusses the protection and restoration challenges for high penetration of inverter-based resources at the distribution level, particularly with grid-connected solar photovoltaic (PV) generation. The discussion starts by providing a brief overview of three cascaded solar PV farms' interruptions in Southern California and their corresponding impact. Then, the distribution level solar PV integration architecture is discussed. The discussion is extended with the nature of inverter fault transients characteristics and available standards on evaluating transients at distribution level. Further, the difficulty of analyzing transients in less than one cycle time frame (i.e., sub-cycle transients) using existing fault analysis techniques and their limitations will be addressed. Finally, a summarized discussion of IEEE 1547 standards and available smart inverter modeling as applied to the aforementioned topic is given.