Distribution substation optimization at primary distribution network planning and visualization of the results

In a primary distribution network planning problem, determination of total number and size (i.e., additional total capacity) and siting of new distribution substations (DS) are among the first important tasks of planners who are responsible from supplying the loads securely, keeping the medium voltage level in defined limits and thereby minimizing losses. This paper presents a methodology to optimize total capacity and siting of new DSs based on spatial load forecast (SLF) results. Objective function minimizes total loss of the primary network while considering security constraints of the network. Given the proportionality between voltage drop and losses, the minimization of losses inherently takes into account minimization of voltage drops as well. First, a grid (250×250 m2) based distribution system is constructed on Microsoft Office (MS) Excel ™ and based on a 10 year SLF assumption which takes into account different growth characteristics of the grids, all the loads are assumed to be supplied by the existing DSs along the planning horizon. Then, the proposed algorithm relaxes the overloaded DSs by placing pre-defined alternative DSs in an optimum manner while satisfying the network security constraints.