الفهرس 
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Abstract
In recent years, more efforts have been made on the integration of PV systems into the grid in order to meet the imperative demand of a clean and reliable electricity generation. Electric power generation through solar energy process is one of the more methods available at the moment, during the operation of solar energy systems there is no gases that lead to greenhouse effect on the environment. The aims of the thesis are: •To develop the general model of a grid connected PV using EMTDC/PSCAD software, depending on the standard parameters of the PV module which provided by the manufacturers. And to develop the PV grid tied to improve power factor of the grid system with induction load at point of common coupling. •To determine the requirements of the Power System Operators (PSO) and the grid owners on the PV system. And to build PV control system to improve the low voltage ride through of the PV system according to the grid code, in addition to coordination between the control system and protection system of the PV. Most of the loads in distribution network tend to inductive loads such as induction motors. Those loads need two types of power; active power for the purpose work performing such as motion and reactive power for providing a magnetic field. Those loads absorb the reactive power from the network, reduce the power factor of the network and cause many losses. In order to overcome this problem, a proposed control strategy of PV systems is introduced for the purpose of power factor correction to prevent the instability of the grid voltage at the point of common coupling (PCC). On the other hand the low voltage ride through capability (LVRT) is a special focus in the grid codes requirements on the PV systems, which addressed primarily the design of the PV controller in such that PV is able to remain connected to the network during abnormal operation condition as well as contribute to voltage support during and after the abnormal conditions. In other words the LVRT capability of PV can be defined as the PV system should stay connected to the grid in the event of grid failures and injects reactive power to prevent grid voltage instability during the grid fault. In this thesis, the LVRT capability of a grid connected PV is improved by developing the control system of the PV to keep the DC link voltage constant without using any hardware protection circuits. The models are implemented using PSCAD/ EMTDC transient simulation package.