For the purpose of finding out the relationship between the fault（overheating fault or even breakdown fault）and the copper shielding layer winding type

an ignition fault occurred at the 35 kV ice melting tube bus in a 500 kV substation AC side has been introduced as an example in this paper. By analyzing the infrared thermal images and grounding current under AC withstand voltage experiments

a copper shielding layer winding circuit model has been established

which is used to analyze the principle of the overheating fault. In the further step

a three dimensional finite element model of 35 kV single core cable is established to study the effect of the copper shielding layer space which may affect the distribution of the cable temperature. The result shows that current flowing through the outer semi-conductive layer is a major cause of cable surface temperature rising

furthermore the interval winding of the copper shielding layer will lead to the current rising at the contact position of the edge and outer semi-conductive layer and the current rising will cause the overheating fault. This type of overheating fault has a close relationship with amplitude and frequency of the applied voltage and the winding space of the copper shielding layer.