الفهرس 
Robust LFC Based on Standard H -OptimizationOnly 14 pages are availabe for public view
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Abstract
There has been continuing interest in designing load-frequency
controllers with better performance during the past 3 decades. The usual
design theory to develop control laws on the basis of the linearised
mathematical model is used. In the application of optimal control
techniques, the controller design is normally based on fixed-parameters.
However, as the system parameters can not be completely known (or can
be changed), controller design based on a fixed parameter model may not
ensure the stability of the overall system if the real plant model differs
from the assumed plant model.
In this research two techniques are applied to design a
supplementary load frequency controller (LFC) for power systems. The
mathematical model used for LFC studies in this thesis considers
parametric uncertainties represented by parameter deviations up to ±50 %
from their nominal values. Moreover, a generation rate constraint for
generating units is considered in the LFC model. The first controller
developed in this research is a robust, fixed parameter controller designed
using the standard Hco optimal regulator. The controller uses the
frequency deviation of the system as a single feedback control signal.
The second controller design is based on the Fuzzy logic concept. The
controller inputs are the frequency deviation and its rate of change. The
Fuzzy rules are deduced so as to simulate the Heo controller dynamic
behaviour. Afterwards, some tuning is introduced to enhance the
dynamic behaviour of the Fuzzy controller. The reliability of the
proposed controllers is proved through a comparison of their responses to
that of a Riccati-equation based robust controller.the design procedures for the two controllers are used to propose
new strategies for the LFC of the Egyptian power system. To
implement the Hco and Fuzzy controllers designed in this thesis, the
program developed by the national energy control center (NECC) of the
Egyptian Electricity Authority to design the load shedding scheme for the
Egyptian power system is used. The Egyptian power system model was
rebuilt using Matlab/Simulink without the load shedding modeL Since
the NECC program considers only the effect of primary reserve concepts,
a secondary loop based on a frequency signal is added to the Simulink
program enable utilizing the effect of secondary reserve concepts. Case
studies are carried out to evaluate the effect of the secondary control loop
on the behaviour of the system frequency. The procedures applied for
designing the Hco and the Fuzzy controllers are used. The two controllers
are added one at a time to the Simulink model with the secondary
controller. The obtained results prove better system performance with the
added controllers.
Finally, the two controllers (Heo & Fuzzy) are applied to a multiarea
system obtained by interconnecting two hypothetical power systems
with the Egyptian power system. The obtained results proved that the
controllers exhibit an excellent performance.