Effect of Temperature and Thermal Ageing of Cable Silicone Rubber Accessories on Interface Pressure of Cable Joints

Abstract

The adequate interfacial pressure of silicone rubber in cable intermediate joints is a basic condition to ensure the normal operation of cable joints, while high temperature and ageing in the operation of actual cables and accessories would affect the magnitude of interfacial pressure. The uniaxial tensile force of two different silicone rubbers for 10 kV cold-shrink joints at different temperatures and thermal ageing times was measured by experiment, and the Yeoh rubber intrinsic structure model was fitted according to the measured data. The material model was embedded into a two-dimensional axisymmetric finite element simulation model of the structure, and the relationship between the interference, temperature, thermal ageing time and interfacial pressure was investigated. The results show that the interfacial pressure increases linearly with the increase in interference. At the same interference, the interfacial pressure at the root of insulating silicone rubber and semiconducting silicone rubber increased by 9.1%, 12.3%, 6.4% and 9.2%, 16.3%, 5.6%, respectively, at 50, 75, and 100 °C compared with room temperature, and the largest interfacial pressure of cable joints was at 75 °C. Using the established ageing life prediction model based on the Arrhenius principle, the service life of the accessories was predicted to be 28.9 years at 90 °C of operating temperature and interfacial pressure greater than 55% of initial interfacial pressure.

Aging Analysis of Semiconductive Silicone Rubber for 10 kV Cold-Shrink Cable Accessories

“…The stress-strain data for the semiconductor silicone rubber at 150 • C, 170 • C, and 200 • C are shown in Figures 3-5, respectively. In order to make the figures clearer and more understandable, only the stress-strain curves for aging periods of 96 h, 360 h, and 720 h are presented in the figures [26].…”

“…The stress-strain data for the semiconductor silicone rubber at 150 °C, and 200 °C are shown in Figures 3-5, respectively. In order to make the figures clea more understandable, only the stress-strain curves for aging periods of 96 h, 360 720 h are presented in the figures [26]. We utilized the experimental data of stress-strain obtained from the tests, im the data into Origin 2022, and then fit the parameters of the Yeoh constitutive mo for thermally aged semiconductor silicon rubber, which are shown in Tables 1-Yeoh constitutive model, C10 represents the initial shear modulus at small strains, ative value of C20 reflects the material softening process during moderate deform and C30 indicates an upward curve at large deformations, representing the harden nomenon during significant strains.…”