Optimal Allocation of Distributed Generation in Distribution Systems

Abstract

The integration of distributed generation (DG) to the power grid has increased in recent years due to their techno-economic benefits for utilities and consumers. The downside of these DG units is that they introduce several challenges to the utilities. One of the critical challenges faced by the utilities from such units is their effect on the protection system settings, location, and coordination. For designing the protection system, fault analysis is carried on the system without considering any DG units. Once the DG units are installed, all previous settings must be updated, since the addition of these units affects the pickup current settings of the protection relays, coordination between the primary and the secondary relays, and even the direction of the fault current. Failing to consider the DG effect on the protection system may lead to serious equipment damage or system failure costing the utility a huge financial setback. Moreover, DG units have many economic and technical effects that must be taken into consideration such as power loss, voltage profile, and thermal overloading. This work proposes a new method for DG allocation in the distribution system through genetic algorithm. The main objective of this work is to optimally allocate DG units to minimize the overall operating costs of the system while taking into consideration its intermittency and the protection system aspects. Simulation results have been developed on a typical distribution system. The optimally allocated DG units resulted in a reduction by 10 % in the overall system costs while upgrading the protection system to withstand the new configuration over the planning horizon.