Optimal placement of underground cables to maximise total ampacity considering cable lifetime

This study presents a novel algorithm for the optimum placement for underground cable in a concrete duct bank to maximise ampacity and also the lifetime of the cable and fluctuation in the input variables. Fluctuations in the operating temperature cable result from variations in factors such as the ambient temperature, the thermal resistivity of the soil and back fill, as well as the loading of the cable. Operating the cable near or above its thermal rating could have an adverse effect on the aging of the cable insulation subsequently reducing the lifetime of the cable. The algorithm reported in this study considers the factors mentioned above and computes the optimum cable placement in the duct bank by calculating simulated lifetimes for the cables. It makes use of an Arrhenius thermal model to calculate the lifetime of the cable as well as the vector immune system algorithm and interior point method to optimise the placement of the cables in the duct bank. The proposed method has been used in a test case to show how cable placement affects the lifetime of the cables in the duct bank.