Impact of Surface Sand Holes on the Electro-Thermal Performance for Crimping Sleeves in 35 kV Cable Joints

Crimping sleeves serve as critical components in cable joints, ensuring both electrical and mechanical connections. The presence of surface sand holes leads to uneven current density distribution, potentially compromising transmission safety. This study investigates the impact of surface sand holes on the heating power distribution of crimping sleeves in 35 kV medium-voltage cable joints. The surface sand holes are modeled as ellipsoidal structures, with their size and location parameterized by four variables: <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$a, b, c$</tex>, and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$L$</tex>. A coupled electro-thermal finite element simulation is conducted to analyze the local maximum and average heating power. The results show that compared with the crimping sleeve without sand holes, the same size sand holes at different locations cause the maximum value of the heat loss power <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\boldsymbol{P}_{\text {max }}$</tex> to change at a rate of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$-17.53 \%$</tex> to 4.46 %, indicating that the sand holes significantly disturb the current density distribution. Based on the complete set of simulation data, a logistic regression model is proposed to assess the safety implications of sand hole size and location on the surface of crimping sleeves.