Optimising the design of low-voltage cable networks

A procedure is described for selecting cables for radially-connected low-voltage distribution networks of given layout, so that the volume of conductor in the network is a minimum. This corresponds to producing a minimum-capital-cost design when the cost of cables varies linearly with their conductor cross-sectional area. The procedure, based on analytical methods for the design of distributors, includes voltage regulation and the current ratings of the cables as limiting factors in the design. It also permits other factors, such as the unbalanced loading of phases and the presence of existing branches, to be allowed for. Results are given for two networks, with given costs for cables, and compared with results from a tried procedure which seeks to minimise costs directly. The comparison indicates that the method can produce good results rapidly. It is concluded that this, coupled with the fact that programming and computation are sufficiently limited for sizeable networks to be handled on a small microcomputer, suggests that it could be a useful design procedure.