الفهرس 
Chapter One: IntroductionOnly 14 pages are availabe for public view
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Abstract
The nonlinear characteristics of various office and industrial equipments connected to the power grid could cause electrical disturbances leading to poor power quality. These electrical disturbances such as sag could destroy certain sensitive equipment connected to the grid or in some cases could cause them to malfunction. These problems are sometimes unpredictable, because they may happen any where at any time. In this thesis treatment of Voltage sag problem is discussed.
This thesis presents detailed fast control characteristics and continuous compensation capability. Modified Flexible AC Transmission System (MFACTS) devices have been modified and adopted to overcome Voltage sag problem. There are so many advantages of MFACTS device; it can increase dynamic stability, loading capability of lines, improve power quality and system security. The key role of MFACTS device is to control the power flow actively and effectively. In other words, it can transfer power flow from one line to another within its capability.
This research work presents detailed improving power system quality using the Modified Flexible AC Transmission Systems (MFACTS) controllers. There are Modified Thyristor Controlled Series Capacitors (MTCSCs), Modified Thyristor Controlled Series Reactor (MTCSR), Modified Static Var Compensator (MSVC) and Modified Static Var System (MSVS). This study focuses on the operation of the MFACTS device under generator fault that may cause any other transmission lines to be overflowed. In this thesis, decision making logic is implemented by using Recurrent Artificial Neural Network (RANN) and by using Adaptive Neuro-Fuzzy Inference System (ANFIS). Total Harmonic Distortion (THD) is studied before and after using MFACTS. The modified algorithm in this thesis is tested on the testing 9 bus system, IEEE 14 bus system, IEEE 30 bus system, IEEE 39 bus system, and IEEE 57 bus system. The obtained results are very promosing. The obtained results indicate the MTCSC is the best type of modified MFACTS.