In order to obtain the electric heating characteristics of three-core fiber composite ground faults

the finite element model of single phase ground fault is established by the electro-thermal coupling finite element method.We first establish a through copper conductors and lead alloy sheathed cable breakdown resistance in the insulating layer to simulate the occur of grounding fault.Then we use the finite element software SOLID69

SOLID90 to simulate the submarine cable conductor layer unit and nonconductor layer.We also combine the intelligence division and sweep division methods to mesh cable model.The temperature distribution of fault current distribution and cable body are obtained through simulation.Results show that the cable in the ground fault occurs with increasing temperature of copper conductor.Due to the ground fault

the fiber unit’s temperature within the layer also increases.We can find the fault location according to the highest point of light unit temperature.Our proposed method provides a theoretical basis for the electrical fault monitoring when using the distributed optical fiber sensing technology.