Thermomechanical Pressure Analysis for HVDC Cables

For some mass-impregnated (MI) paper insulated HVDC cables, unacceptably high pressures or pressure drops occur at the insulation-sheath interface under rapid loading changes, due to a strong impregnant thermal expansion or contraction. As this can degrade cables by either causing sheath plastic deformations or introducing voids into the insulation, it is important to investigate/model this thermo-mechanical phenomenon. Based on the theory of elasticity, this paper presents an analytical calculation of interfacial pressures as a function of the cable loading. Results obtained will benefit both cable operators and manufactures by provide guidelines of rating calculations and insulation designs, following a thermo-mechanical constraint.