Volume 01 issue 03

This work presents a method for solving the problem of load flow in electric power
systems including a wind power station with asynchronous generators. For this type
of power station, the generated active power is only known and consequently the
absorbed reactive power must be determined. So we have used the circular diagram
at each iteration and by considering this node as a consuming node in the load flow
program. Since the wind speed is not constant, the generated power is neither
constant. To predict the state of the network in real time, we have used the
artificial neural networks after a stage of training using a rich base of data.

This paper presents the results of a simulation study on a 12 pulse HVDC (High
Voltage Direct Current) using a system in Matlab/Simulink. The object of the
study is to investigate the steady state and dynamic performance of the system.
First we examine response of current regulator after change in current reference in
order to see the behavior of the controllers in controlling the desired current. Next,
we present the digital simulation of a test system and show the response to a DC
fault in the line and the AC fault at inverter side. The results are evaluated to
enhance the recovery of the system from the disturbances for a full range of typical
disturbances. The presented approach benefits from Simulink’s advantages in
modeling and simulating dynamical systems.

In this paper, a linear electromagnetic actuator with moving parts is analyzed. The
movement is considered through the modification of boundary conditions only using
coupled analytical and finite element analysis. In order to evaluate the dynamic
performance of the device, the coupling between electric, magnetic and mechanical
phenomena is established. The displacement of the moving parts and the inductor
current are determined when the device is supplied by capacitor discharge voltage.

This paper is devoted to the comparative evaluation of the two modulation
strategies developed for multilevel inverters control : the harmonic elimination
technique with voltage control (OHSW) and the optimal minimization of the total
harmonic distortion method (OMTHD), which are a very important and efficient
strategies of eliminating selected harmonics from spectrum of the output voltage or
minimizing its total harmonic distortion in order to improve its quality. First, we
describe briefly the basic idea and concept of each technique. Then, we present a
study of the performances of each one by the means of a comparison between them.
Simulation has also been presented to establish the effectiveness of the proposed
analysis. Finally, we conclude with scope of further work.

An optical strain gauge is developed and characterised for an active pantograph for
high-speed electrical trains applications. Indeed, the pantograph is subjected to a
continuous impact forces when it makes contact with the 25 kV overhead ac line.
To detect load behaviour experienced, by the electrical pick-up on the pantograph,
tests were carried out. The results show that the strain gauge responded linearly to
static load over the range 0 to 80 Newton. Also, a high repeatability was achieved
and acceptable amount of hysterisis was experienced. The influence of the
electromagnetic field on the optical strain gauge was sufficiently weak to be
neglected. Beside that the optical strain gauge has proved a high resistance to time
varying forces.