Study on Evolution Mechanism of Single-Phase-to-Ground Fault Characteristics in Multi-Mode Neutral Grounding Mode of Large Generators

This study develops fault analysis models for three generator neutral grounding configurations: arc suppression coil, high-resistance, and ungrounded systems. The models establish fault current distribution principles and grounding parameter criteria. Using MATLAB simulations, we quantify characteristic evolution patterns of zero-sequence voltage and neutral current under varying transition resistances, elucidating grounding-mode-dependent fault characteristics. Multi-scenario comparisons demonstrate distinct amplitude and phase characteristics of fault signals across various grounding configurations. Finally, through the actual action case on site, the correctness of the simulation results is serious, which provides theoretical support for the grounding protection configuration and fault diagnosis of generator stator winding.