  With the increasing rate of power consumption, many new distribution systems
need to be constructed to accommodate connecting the new consumers to the power
grid. On the other hand, the increasing penetration of renewable distributed
generation (DG) resources into the distribution systems and the necessity of
optimally place them in the network can dramatically change the problem of
distribution system planning and design. In this paper, the problem of optimal
distribution system planning including conductor sizing, DG placement,
alongside with placement and sizing of shunt capacitors is studied. A new
Binary-Selective Particle Swarm Optimization (PSO) approach which is capable of
handling all types of continuous, binary and selective variables,
simultaneously, is proposed to solve the optimization problem of distribution
system planning. The objective of the problem is to minimize the system costs.
Load growth rate, cost of energy, cost of power, and inflation rate are all
taken into account. The efficacy of the proposed method is tested on a 26-bus
distribution system.
