الفهرس 
IntroductionOnly 14 pages are availabe for public view
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Abstract
As the yearly electric energy demand grows, there is a significant increase in the distributed generation (DG) penetration level to fulfill this increase in demand. Interconnecting DG to an existing distribution system provides various benefits to several entities as for example the owner, utility and the final user. DGs provide an enhanced power quality and more reliable of the distribution system. However, the integration of DG into existing networks has associated with several technical, economical and regulatory questions. Penetration of DG into an existing distribution system has many impacts on the system, with the power system protection being one of the major issues. The distribution system protection has traditionally been designed assuming the system to be radial. DG causes the system to lose its radial power flow, besides the increased fault level of the system caused by the interconnection of the DG, which means that the coordination might not be held. In this thesis, an electric Distribution system connected to DG is modeled and simulated using Matlab program. Moreover, the protective devices used to protect the distribution system are designed and built using the Matlab/Simulink. This model is used to examine the effect of different locations and penetrations of the DG sources on the coordination of the directional overcurrent relay (DOCR). A novel method based on clonal selection algorithm of artificial immune system (AIS) is proposed for optimal coordination of overcurrent relays in distribution system connected to DGs. This method is used to find (TDS) and (Ip). The proposed AIS algorithm is implemented using Matlab program. The obtained settings have been set for the relays in the distribution system and it will be tested with different conditions such as different DG penetrations, different DG locations and different fault types. The objective of the proposed algorithm is to obtain the optimal setting of DOCRs and make it adaptive with any DG penetration level and location. The coordination of DOCRs by this algorithm is implemented on a 5- buses distribution system and compared with simplex method and differential evaluation coordination method. Finally to test the accuracy of the proposed method, the proposed algorithm is implemented on a large distribution system (11- bus system) to obtain the minimum operating time according to any system changes.