Accurate Arc Modeling of Single-Phase Arc Grounding Fault in Distribution Network and Research on Dynamic Arc Energy

Aiming at the problem of energy exchange in the arc channel of single-phase arc grounding in distribution networks, this paper establishes a three-dimensional, single-phase arc grounding field-circuit coupled mathematical model based on magnetohydrodynamics. It analyzes the process of arc energy exchange, considers the competitive relationship among the input energy, dissipated energy, and the energy of arc itself under varying wind speeds, and conducts artificial single-phase arc grounding tests in actual distribution networks to validate the accuracy of the arc mathematical model. The research findings indicate that the simulation calculations begin with a voltage phase angle of 0°. At a wind speed of 1 m/s, the energy of arc itself increases in a step-like manner, and the arc burns stably. At wind speeds of 3 m/s and 5 m/s, the energy of arc itself exhibits a phenomenon of repeated fluctuations, rising to a peak before rapidly declining. At this moment, the arc does not extinguish; rather, the extinguishing occurs at the first current zero-crossing point following this peak. Higher wind speeds facilitate the extinguishing of the arc. The first extinguishing times corresponding to wind speed of 3 m/s and 5 m/s are 284 ms and 204 ms, respectively. After the arc extinguishes, a re-ignition phenomenon occurs, with higher wind speeds resulting in a longer interval between extinguishing and re-ignition.