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Defect Morphological Characteristic of Cold- Shrinkable Cable Terminal and Its Partial Discharge Analysis Based On Finite Element Method

LI Nan, DENG Gang, KONG Bing

The 35 kV prefabricated silicone rubber cable terminal defect models were established and simulated in the static electric field utilizing the finite element method. Triangle and isosceles trapezoid models were established to simulate the incised defects and sunken defects where partial discharge might occur. Defects with different sizes and same length-width ratio were built to calculate the maximum field strength. The distribution of maximum field strength was drawn into curves with the least square interpolation data. The results indicate that the fracture of the copper shield is easy to cause electric field distortion and partial discharge. The electric field strength of incised defect is higher than that of the sunken one in the same place. Due to the evacuated effect of the stress cone, it is less likely to cause partial discharge in the fracture of semi-conducting layer. It may cause partial discharge in the long run if there is micro air gap in area between the fracture of copper shield and semi-conducting layer. The conclusions have certain guidance on the design, manufacture and installation of cable terminal.