Multi-physical Field Simulation of Permanent Arc Grounding Fault in 110 kV High Voltage Cable

In 110 kV cable systems, most faults are arc grounding faults. Due to the solid grounding of neutral point, short circuit currents can reach tens of thousands of amperes. Arcs of high short circuit currents can cause extremely high energy release into the surrounding environment. This is quite likely to result in a large number of accidents. In the majority of existing studies, the black box model is used to describe the behavior of the permanent arc grounding fault in cable. However, it cannot solve for internal characteristics. In order to solve the ablve problem, the magneto hydro dynamic (MHD) model was used to study permanent arc grounding faults of high voltage cables. The model was also modified to account for the structure inside the cable. The simulation results show that the maximum temperature inside the arc column can reach 2.2 × 10⁴ K at a short circuit current of 1 kA RMS. When the current is respectively positive and negative peak, the arc voltage can reach 167 V and −155 V. The arc average power is 131 kW. This research paper provides a theoretical basis for the characterization of permanent arc grounding faults and the formulation of relay protection strategies.