الفهرس 
AbstractOnly 14 pages are availabe for public view
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Abstract
Flexible Alternating Current Transmission System (FACTS) devices are used in modern power system to increase the capacity of the transmission lines and dynamic/transient stability limits. During steady state operation and fault condition, FACTS devices have a great effect on voltage and current values. These effects insert additional challenges to the protection of the power system. These challenges comprise quick changes in the line’s impedances, currents, power angles, and the transients during the faults and control act of FACTS devices. So, it is vital to study the performance of the existing protective system schemes used to protect transmission networks in the presence of FACTS devices. Distance relays are the main protection of transmission lines. It is important that distance relays work correctly regardless of any dynamic changes. The mal-operating of the distance relays lead to improper tripping. This will reduce the reliability and security of power system. Moreover, the power system can start cascaded tripping and blackouts. So, it is vital to study the performance of distance relay schemes in the presence of FACTS devices and modify these schemes for achieving grid security and integrity.
In this thesis, a complete model for distance relay using MATLAB/Simulink environment is introduced and the model performance is tested in the presence of unified power flow controller [UPFC]. A proposed distance relay scheme depends on phasor measurement units (PMUs) also introduced to overcome the mal-operation of the distance relay in the presence of the UPFC.