International Review of Automatic Control (I.RE.A.CO.), Vol. 5, N. 2
ISSN 1974-6059 March 2012
Manuscript received and revised February 2012, accepted March 2012 Copyright © 2012 Praise Worthy Prize S.r.l. - All rights reserved
179
Frequency Control of Isolated Network with Wind and Diesel
Generators by Using Adaptive Artificial Neural Network Controller
Syed Q. Ali
1
, Hany M. Hasanien
2
Abstract – Due to increasing interest in renewable energy applications, wind energy conversion
systems have gained a lot of significance worldwide. Wind generators produce unpredictable
output fluctuations which result in variations of the network frequency thereby affecting the power
system. This results in a degraded power quality and restricts the penetration of wind energy,
especially for microgrid or island network applications. This problem needs to be addressed to
ensure the expansion of the wind energy component in the overall world energy mix. This paper
addresses the aforementioned problem by the application of an adaptive artificial neural network
(ANN) controller for controlling the frequency of an islanded network with a high penetration no
storage wind diesel (HPNSWD) system. The proposed controller is validated by computer
simulation analysis using MATLAB-Simulink. The effectiveness of the proposed controller is then
compared with a PID controller. Copyright © 2012 Praise Worthy Prize S.r.l. - All rights
reserved.
Keywords: Adaptive Artificial Neural Network (ANN) Controller, Wind Turbine, Isolated
Network, Network Frequency, High Penetration No Storage Wind Diesel (HPNSWD)
System
Nomenclature
ANN Artificial Neural Network
CAN Controller Area Network
GTO Gate Turn Off
PID Proportional, Integral and Derivative
PLL Phase Locked Loop
A Area covered by the rotor in meter squared (m
2
)
C Capacitance in Farad(F)
C
p
Power coefficient
K
p
Proportional gain
K
i
Integral gain
K
d
Derivative gain
L Inductance in Henry (H)
M Magnetizing inductance in Henry (H)
P Power in Watts (W)
T Electromagnetic torque in Newton meters (Nm)
e(t) Error
f Frequency in Hz
f
i
Activation function of the ANN controller
i Instantaneous current in Ampers (A)
m(t) Controller output signal
r Resistance in Ohms ( )
u Wind speed in meter per second (m/s)
v Instantaneous voltage in Volts (V)
w
ij
Weighting factor of the ANN neurons
x
j
Input signal for each neuron of the ANN
controller
Step change in error for the ANN controller
Wind turbine blade pitch angle in degrees (
o
)
Tip speed ratio
Air density in Kilogram per meter cubed
(kg/m
3
)
Flux linkage in Weber (Wb)
Electrical rotor speed in radians per second
(rad/s)
I. Introduction
As a result of conventional energy sources
consumption and increasing environmental concern,
efforts have been made to generate electricity from
renewable sources, such as wind, solar, biomass etc.
Institutional support for wind energy sources, together
with the wind energy potential and improvement of wind
energy conversion technologies, has led to a fast
development of wind power generation in recent years
[1]-[3]. However, the frequency variation of power
system due to wind generator output fluctuations is a
serious problem. If installations of wind farms continue
to increase, frequency control of power system by the
main sources, that is, hydraulic and thermal power
stations will be difficult in the near future, especially in
an isolated network like a small island which has weak
capability of power regulation. In such a case, the
installation may be restricted even though it is a small
wind farm. Though there is such a difficulty, an
introduction of the wind energy utilization is much
effective in an isolated power system, because main