الفهرس 
V()LT" ~ "(;E STABILITY PHIC" ~ "()ME" ~ "()" ~ " ()F A(:fI)(: P()WEROnly 14 pages are availabe for public view
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Abstract
This thesis deals with modeling, simulation, analysis, and control of the
voltage stability problem of ACfDC systems. The system under study
is assumed consisting of two similar AC systems, two star-delta
converter transformers, rectifier and inverter stations, AC filters and
shunt compensators. The system is modeled using the simulink blocks
and tools under MATLAB software package. Details of the models
used for the different system components are given in the thesis.
The system is modeled and simulated for two modes of operation;
normal mode of operation (Mode A) and abnormal mode of operation
(Mode B). The modeling and simulation technique presented in the
thesis proved to be powerful and versatile as it provides fast analysis of
the effect of different system conditions, different system parameters,
and different control schemes.
This model is used to analyze the ordinary transient performance of the ~
system under study when operated with the normal or the abnormal
control mode. The simulation results and waveforms of different
system variables such as, AC and DC voltages, AC and DC currents,
active and reactive powers, ...... etc., for both rectifier and inverter
stations are presented. These results confirm the validity of the
MATLAB models and simulink simulation of the system under study.
The voltage stability problem is investigated when the system under
study is subjected to power disturbances. The results demonstrate the
effect of some of the system parameters on the voltage instability of the
Abstract
AC/DC system. These parameters are the system reactances and the
inverter transformer tapping. The effect of the system initial operating
condition and level of power disturbances on the voltage instability
phenomenon is also investigated. The investigations are extended to •.
cover both modes of operation (modes A and B). It has been found
that mode B is more vulnerable to voltage instability than mode AFinally, the thesis presents a proposed method for curing the voltage
instability phenomenon. This method is based on limiting the de
current of the system. The results demonstrate the effectiveness of this
method for curing the voltage instability phenomenon under both
modes of operation and at different operating conditions