Development of the Short-Circuit Capacities Curves for Distribution Systems Planning Using Matlab

The calculations of the short-circuit capacities (SCC´s) along a primary feeder is essential for determining the ratings of protective devices of the distribution systems, especially in the planning stage. According to the calculation results, the interruption capacities (ICs) that shall be able to withstand the mechanical and thermal stresses resulting from maximum flow of short-circuit current through them of the protection devices were evaluated. Therefore, an easy, straightforward, rapid and systematic method, the complex short-circuit MVA method was employed to estimate the SCC´s in this paper, the SCC´s along a primary feeder dependent on the related parameters and network structure were represented by simple formulas and illustrated by curves that plotted in Matlab. It is more convenient for the distribution engineers to select the ratings of protective devices and planning the distribution systems by the developed SCC´s curves