Zero-Sequence Component Blocking for Single-Phase Ground Fault in Transformerless SOP Flexible Interconnected System

With the rapid development of flexible interconnected distribution networks, the disadvantage of large site area for transformer in flexible interconnected systems is becoming increasingly prominent in practical applications. To deal with this problem, the transformerless SOP flexible interconnection system is proposed, the characteristics of zero sequence components on the fault free side when a single-phase grounding fault occurs in this system and the universal zero sequence interlocking strategy are analyzed. Simulation based on PSCAD shows that when different types and grounding methods of converters are put into this strategy, the zero sequence components on the fault free side are reduced to an ideal state