Techno-Economic Issues with Increasing DG Penetration level in Sub-Transmission System

The increasing interest in utilizing Distributed Generation (DG) in transmission system is due to rise in energy demand, restriction in new transmission lines, deregulated power and utility limitations. Introduction DG into the electrical network can improve its performance technically. Both DG placement and its penetration level become critical issue for both utility and DG owners. This paper presents the extent to which DG effect the power losses depending on the type of DG, its penetration level (PL) and its optimal location. In this paper, optimal DG placement and sizing in electrical network is found by using a Directed Bee Colony (DBC) optimization algorithm. The objective is to reduce the power losses and enhance voltage profile of the electrical system. The effectiveness of the DBC had been tested on IEEE 14-bus sub-transmission system and is compared with results obtained with Particle Swarm Optimization (PSO) method. As the PL of 55-60% and 70-75% is achieved the real and reactive power losses begin to increase respectively for DGs of type-2 in the electrical system. It is also observed that the net saving cost due to DG placement is beneficial up to 65% PL of DG.