Optimal allocation of SPV based DG system for loss reduction and voltage improvement in radial distribution systems using approximate reasoning

Optimal siting and siting of distributed generation (DG) is a key for loss minimization and improvement of voltage profile in distribution systems. The present paper proposes a methodology for optimal siting and sizing of solar photovoltaic (SPV) based DG system in radial distribution systems, so that the electrical power losses in the system can be minimized while maintaining the voltage profile in the system within the specified limits. The SPV based DG system supplies the active power in the distribution system at the node where it installed because most of the invertors used for grid interfacing of SPV based systems are current source invertors. The losses and voltage profile in the system is evaluated using a load flow program. Voltage along with active power loss reduction index of each node is fed into fuzzy expert system (FES) whose output is DG placement suitability. DG is then placed at the node with the highest suitability provided voltage constraints are not violated. Exact loss formulae is then used to determine the size of the DG to be placed at the incoming node which was found using FES.