Sensitivity analysis of modal quantities for underground cables

An accurate mathematical model, which takes into account both earth and conductor-sheath skin effects, is utilised for the computation of the high-frequency modal-attenuation constants and phase velocities of underground cables. The sensitivities of these quantities to cable dimensions, material properties, earth resistivity, spacing between cables, cable depth and frequency are evaluated for a typical underground cable system. The sensitivity analysis makes it possible to establish the effect of each parameter on modal propagation. The method of calculating the sensitivities can easily be extended to a crossbonded cable system provided the equivalent homogeneous parameters of the major section are determined