Thesis (M.Sc.) - Cairo University -Faculty of Engineering - Department of Electrical Power and Machines

The power plants feed loads by power through transmission lines and distribution systems due to large distance between power plants and loads. Nowadays, load demand increases rapidly, this increase requires new plants, transmission lines and distribution systems, which are more expensive. Therefore, distributed generation is used to solve this problem. The installation of inverter based Distributed Generation (DG) has been increasing rapidly in recent years, especially photovoltaic (PV) systems. Such increased penetration will result in decreased short circuit ratio (SCR) which could decrease on the allowable limit that determined by inverter manufacturer. SCR is very important factor for inverter as inverter control depends on this value (SCR must be {u2265} specific number) which is determined by inverter manufacturer, if this value becomes (SCR< this specific number): DG will make voltage fluctuations, DG will inject harmonics to power grid and system will become unstable. In this thesis, the maximum DG penetration level is determined taking into consideration (SCR). This study is considered as a Mixed Integer non linear programming (MINLP) problem where SCR is determined using short circuit calculations .The maximum DG penetration level based on optimal location and DG size is determined using particle swarm optimization (PSO) algorithm and Newton Raphson is applied as a load flow technique. The proposed formulation is tested on IEEE 30 bus system. The results show that the higher penetration levels would be achieved by using the DG decentralized technique

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