Analysis and Modeling of Physical Evolution Mechanism for High-Resistance to Low-Resistance Grounding Faults in 10 kV Cable Joints

Currently, the lack of analysis and applicable circuit models for the evolution of cable joint faults is responsible for explosions or fire accidents in the distribution network system. In this paper, the modeling of high-resistance to low-resistance grounding faults for 10 kV cable joints is investigated. Firstly, the physical evolution from high-resistance to low-resistance grounding faults in 10 kV cable joints is analyzed. Secondly, the common discharge characteristics under different evolution stages are extracted by simulation experiments and fault-recording data. Thirdly, an interface breakdown circuit model and a radial breakdown circuit model are established to quantitatively describe the high-resistance to low-resistance grounding faults of cable joints. Fourthly, the corresponding arc resistance models are proposed, and the controlled parameter values of the models under different evolution stages are given. Finally, the fault identification control model is implemented for relay protection. This paper provides theoretical and modeling support for the fault identification of 10 kV cable joints, filling the knowledge gap of this critical fault type in relay protection.