Optimal determination of the number, capacity and location of DGs to improve the coordination of overcurrent relays in distribution networks

Increasing the penetration rate of DG (Distributed Generation) units has various advantages for the network. In addition to various advantages, the use of DGs has problems, such as the emergence of protection problems in the network, which is caused by the increase in the penetration rate of DG units. To maximize the benefits of DGs, such as reducing network power losses, it is necessary to choose their location and capacity correctly. To lessen the adverse effects of DGs in the network, it is also necessary to find the optimal location and capacity of Fault Current Limiters. Then, the optimal number of DGs was determined, the number of FCLs was changed from one to five, and the effects on the results of the problem were investigated and the optimal number was determined. Finally, by knowing the number of FCLs and DGs, their optimal location and capacity were determined simultaneously. In this paper, by placing three FCLs, the protection problems caused by the presence of DGs have been solved. It can be seen that one of the most suitable locations to install these limiters is in series with distributed generation sources and at the beginning of the feeder. Finally, by adjusting the settings of three overcurrent relays and implementing appropriate values for FCL, the protection issues have been resolved.