Study on Pressure Variation Characteristics of Cable Accessories Interface under Temperature Cycling

Interfacial pressure is one of the key factors that determine the insulation strength of cable accessories. However, the cable accessories will relax due to the temperature cycling during operation. Therefore, it is worth to study the change regulation of the interfacial pressure of the cable accessories with the temperature. In this study, an interfacial pressure acquisition device is designed by the built-in pressure sensor. The interfacial pressure of 10 kV cold shrinkable cable joint is measured by the device at 25°C and 130 °C respectively. Meanwhile, the joint thickness and inner diameter is recorded to compare the changes of joint geometry before and after aging. Then, the cable joint is built by the finite element simulation software, and the simulation results are compared with the measured data to verify the validity of the data. With the increase of the temperature cycle time, the interfacial pressure of the cable joint at room temperature decreased by 15.9%, while the interfacial pressure at high temperature increased by 11%. Experimental results proved that after the temperature cycle of the cable joint, the geometric dimensions of the cable joint changes, and the stress relaxation increases. When the cable joint work at high temperatures, the interfacial pressure of the cable accessories increases, while the cable accessories work at room temperature, the interfacial pressure decreases, resulting in a decrease in the electric field strength of the cable accessories.