Modeling and Analysis of Equivalent Load Characteristics in Flexible Arc Suppression for Single-Phase Ground Faults

Single-phase ground faults in distribution networks can lead to severe safety hazards, such as electric shocks and forest fires. Although inverter-based flexible arc suppression devices(FASD) can effectively mitigate fault currents, their control systems must achieve stable tracking of target reference values under complex and variable fault conditions. To address this issue, this paper establishes an equivalent load circuit model for the FASD based on the principles of flexible arc suppression. The impedance characteristics and variation patterns of the equivalent load circuit under different single-phase ground fault conditions are analyzed in depth. The study reveals that the equivalent load impedance of the FASD is influenced by the combined effects of line impedance, ground capacitance, and transition resistance, exhibiting inductive, resistive, or capacitive characteristics. As the transition resistance increases, the impedance characteristic transitions from inductive to capacitive and remains constant. These findings provide theoretical support for the design of control strategies and parameter optimization of FASD.