Allocation planning tool for determining the optimal location and sizing of distributed generations in provincial electricity authority of Thailand

Distributed generations (DG) can be used to enhance power generation systems and improve distribution system efficiency. However, the installation of DG units at non-appropriate location and sizing can result in negative impacts such as an increasing in power losses and violations of system constraints. In this paper, a new DG allocation planning tool is developed for determining the optimal location and sizing of DG in practical distribution systems. The proposed planning tool is developed by writing DIgSILENT Programming Language (DPL) script in DIgSILENT PowerFactory software. The optimally placed optimal power flow (OPF) with DG is formulated as a minimization of energy losses function and a maximization of benefit to cost ratio, subjected to system constraints including real and reactive power generation, line and transformer loading, voltage profile, step voltage change, reverse power, energy losses, short circuit level, and DG operating limits. All possible locations and sizes of DG installations are evaluated and then the optimal solution is selected from the best objective function value obtained. Test results on the practical 9-bus and 437-bus distribution systems taken from Provincial Electricity Authority (PEA) of Thailand indicate that the proposed planning tool can be used to determine the optimal DG allocation without violation of system constraints.