الفهرس 
Abstract
Aims of the Present WorkOnly 14 pages are availabe for public view
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Abstract
Use of self-excited induction generator (SEIG) is becoming popular for the
harnessing the renewable wind energy resources. A simple approach for computing
the performance characteristics of a cage induction machine operating as a SEIG in
stand-alone mode is developed. The main feature of the approach is that the
proposed SEIG model completely avoids the tedious and erroneous manual work
of segregating the real and imaginary components of the complex impedance of the
machine for deriving the specific model for each operating modes. Moreover, any
element, like the core loss component, can be included or excluded from the model
if required.
For comparison the steady state analysis of the SEIG under balanced
conditions using different conventional iterative methods (Newton-Raphson and
the Complex Impedance Matrix Method) is presented. MATLAB programming is
used to predict the steady state behaviour of SEIG. The main disadvantage of these
conventional methods is that the determination of the steady-state analysis of the
SEIG is tedious and time consuming task. Moreover, inclusion of core loss
resistance will increase the order of the equations.
Particle swarm optimization (PSO) algorithm has been applied to predict the
minimum value of the capacitance necessary for the onset self excitation of SEIG.
Also it used to predict the minimum value of capacitance necessary to maintain the
generator terminal voltage at a preset value under specific load and speed
conditions. To confirm the validity, accuracy and simplicity of the proposed
method is compared with those obtained with the conventional methods.
The use of Flexible Alternating Current Transmission Systems (FACTS)
device called Static Synchronous Compensator (STATCOM) to control the
reactive power and keep the output voltage of stand-alone SEIG at rated value
under normal and abnormal conditions such as, de-excitation due to over-loading
with balanced and unbalanced load conditions, line to ground fault, symmetrical
fault, and variation of wind turbine speed. The dynamic model of the system is
developed and a methodology to decide the ratings of STATCOM components
such as the DC bus capacitor, AC side filter and Insulated Gate Bipolar
Transistors (IGBT) is presented.
The STATCOM-controlled algorithm was realized by controlling the source
current using two control loops with Proportional Integral (PI) controller: one for
controlling the SEIG terminal voltage and the other for maintaining the DC bus
voltage. The simulated results show that by using a STATCOM based voltage
regulator the SEIG terminal voltage can be maintained constant. A comparison
between the Static VAR Compensator (SVC) and STATCOM device for reactive
power compensation is carried out and analyzed. The results show that the
STATCOM is superior above SVC in sense of STATCOM recover the terminal
voltage in less time and STATCOM injected reactive current does not affected by
terminal voltage like SVC .
The dynamic performance of grid connected induction generator driven by
wind turbine without and with STATCOM is obtained and discussed under
different operating and wind conditions. The digital results prove the effectiveness
of STATCOM in terms of fast response and fast recovery the terminal voltage.