Increasing the ampacity of underground cable lines by optimising the thermal environment and design parameters for cable crossings

Abstract

The problem of optimising the thermal environment and design parameters of underground cable lines for cable crossings with the aim of increasing the ampacities of cables is considered in this paper. Particle swarm optimisation (PSO) algorithm, formulated as a continuous non-linear optimisation problem with constraints, for solving this hot spot problem is applied. It is found, using the PSO algorithm, that there are a suitable size of cable bedding and an arrangement of cables within that bedding, which can eliminate or significantly mitigate the hot spot effect without the use of any additional cooling equipment. In this manner, the ampacities of both crossing cable lines increase by about 15% on average with respect to the case of a similar crossing with installation parameters commonly used. In addition, it is shown how the cross-sectional areas of the conductors and metal screens and the metal screen bonding methods affect the optimal solution.