The effect of extreme ambient temperatures on interface pressure of different interfaces in cable accessories under thermal cycling

Climate change introduces formidable challenges to power system infrastructure. Extreme weather and temperature changes are increasing the risk of limiting the withstanding capability of transmission and distribution equipment to stresses. This study employs a 2D thermomechanical model for a 110 kV cable joint, investigating the impact of extreme ambient temperatures on thermally induced stresses at solid-solid interfaces. The model incorporates temperature-dependent thermal expansion and elastic modulus. The changes in radial and hoop stresses are calculated for four types of interfaces; cross-linked polyethylene-silicone rubber (XLPE-SiR), XLPEEPR Ethylene Propylene Rubber, (XLPE-XLPE), and (SiR-SiR). It is found that at extremely low ambient temperatures, the risk of a drop in radial pressure is higher. Moreover, the change in hoop stress at extremely low ambient temperatures elevates the initial tensile stresses at the interface. SiR-SiR interfaces experienced the lowest variations in pressure while XLPE-XLPE interfaces demonstrated the highest variations. A sensitivity analysis is performed to highlight the significant influence of material properties and ambient temperature. The ambient temperature has a positive impact on radial thermal stress and a negative influence on thermal hoop stress. The model proposed in this research can be used to explain pressure fluctuations that could lead to failures at extreme ambient temperatures. This research offers critical insights into the performance of cable joint materials under extreme conditions, contributing to the design of more resilient power infrastructure.