Computation of Transient Temperatures and Pressures in Oil Filled Cables

A calculation method has been developed for the transient temperatures and pressures in oil filled cables. The method models the thermal and pressure fields as two coupled resistance-capacitance electrical networks. This conceptually simple analog is extended to include the effects of cable-sheath elasticity, oil compressibility and sheath thermal expansion. The variation of surrounding temperature along the route and changes of oil viscosity and copper resistance with temperature are considered. The method has been implemented as a computer program and applied to the analysis of an 18 km HVdc cable system in a deep tunnel.