Power Quality Harmonics Anal. and Real Measmts. Data

290 Pages·2011·10.78 MB·English

by  G. Rey

POWER QUALITY
HARMONICS ANALYSIS
AND REAL
MEASUREMENTS DATA

Edited by Gregorio Romero Rey
and Luisa Martinez Muneta
Power Quality Harmonics Analysis and Real Measurements Data
Edited by Gregorio Romero Rey and Luisa Martinez Muneta

Published by InTech
Janeza Trdine 9, 51000 Rijeka, Croatia

Copyright © 2011 InTech
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First published November, 2011
Printed in Croatia

A free online edition of this book is available at www.intechopen.com
Additional hard copies can be obtained from [email protected]

Power Quality Harmonics Analysis and Real Measurements Data, Edited by Gregorio
Romero Rey and Luisa Martinez Muneta
p. cm.
ISBN 978-953-307-335-4
free online editions of InTech
Books and Journals can be found at
www.intechopen.com

Contents

Preface IX
Part 1 Measurements 1
Chapter 1 Electric Power Systems Harmonics
- Identification and Measurements 3
Soliman Abdelhady Soliman
and Ahmad Mohammad Alkandari
Chapter 2 On the Reliability of Real Measurement Data
for Assessing Power Quality Disturbances 69
Alexandre Brandao Nassif
Chapter 3 Voltage Harmonics Measuring Issues
in Medium Voltage Systems 89
Jarosław Łuszcz
Part 2 Converters 109
Chapter 4 Study of LCC Resonant Transistor DC / DC
Converter with Capacitive Output Filter 111
Nikolay Bankov, Aleksandar Vuchev and Georgi Terziyski
Chapter 5 Thermal Analysis of Power
Semiconductor Converters 131
Adrian Plesca
Part 3 Harmonic Distortion 151
Chapter 6 Improve Power Quality with High Power UPQC 153
Qing Fu, Guilong Ma and Shuhua Chen
Chapter 7 Characterization of Harmonic Resonances
in the Presence of the Steinmetz Circuit
in Power Systems 171
Luis Sainz, Eduardo Caro and Sara Riera
VI Contents

Chapter 8 Stochastic Analysis of the Effect
of Using Harmonic Generators in Power Systems 195
Mohsen Abbas Pour Seyyedi and Amir Hossein Jahanikia
Part 4 Industrial Environments 209
Chapter 9 Harmonics Effect in Industrial
and University Environments 211
M.H. Shwehdi
Chapter 10 Power Quality Problems Generated by Line
Frequency Coreless Induction Furnaces 235
Angela Iagăr
Chapter 11 Harmonic Distortion in Renewable Energy Systems:
Capacitive Couplings 261
Miguel García-Gracia, Nabil El Halabi,
Adrián Alonso and M.Paz Comech

Preface

Nowadays, the rapid growth of power electronics in industry and the presence of
products based on electronic components in enterprises, institutions, shops, small
businesses, residences, etc. and transport systems has been welcomed by the people
who already use it due to its increased productivity within all areas. The problem of
this increasing use of power electronics equipment is the important distortions
originated; the perfect AC power systems are a pure sinusoidal wave, both voltage
and current, but the ever-increasing existence of non-linear loads modify the
characteristics of voltage and current from the ideal sinusoidal wave. This deviation
from the ideal wave is reflected by the harmonics and, although its effects vary
depending on the type of load, it affects the efficiency of an electrical system and can
cause considerable damage to the systems and infrastructures. Logic and electronic
control circuits, among others, may be affected if the supply voltage has distortions,
leading to, for example, damage in the consumer equipment, and noise in the different
installations or unsafe working conditions. In other cases the harmonic current passes
through transmission lines and causes harmonic voltage on the loads connected at the
end of the line, but this will be dealt with in another book.
Ensuring optimal power quality after a good design and devices means productivity,
efficiency, competitiveness and profitability. Nevertheless, nobody can assure the
optimal power quality when there is a good design if the correct testing and working
process from the obtained data is not properly assured at every instant; this entails
processing the real data correctly. To ensure a precise measurement of the electrical
power quantities, different processing techniques are necessary. The possibilities range
from the design of the overall system to the testing and training of devices, checking
the influence of the final design and behaviour laws in a virtual environment similar to
the real one. One properly designed simulator would allow for checking the technical
specifications in order to find contradictions that may be introduced during the design
of the system, and their subsequent correction.
In the following chapters the reader will be introduced to the harmonics analysis from
the real measurement data and to the study of different industrial environments and
electronic devices. The book is divided into four sections: measurements, converters,
harmonic distortion, and industrial environments; a brief discussion of each chapter is
as follows.
X Preface

Chapter 1 discusses the sources of harmonics and the problems caused to the power
systems, and also model the voltage and current signal to account for the harmonics
components when the signal is a non-sinusoidal signal. Additionally, it estimates the
parameters of this signal in order to suppress the harmonics or eliminate some of
them, and identifies and measures the sub-harmonics. Finally, it models the harmonic
signals as fuzzy signals, identifying the parameters by using static and dynamic
algorithms. Chapter 2 encompasses the poor reliability of the real measured data used
for several applications dealing with power quality disturbances, and proposes a set of
reliability criteria to determine the data quality, which can be directly applied to
recorded data and used to determine which data are to be used for further processing,
and which data should be discarded. Chapter 3 presents the problems of voltage
transformers and voltage harmonic transfer accuracy, which are usually used for
power quality monitoring in medium and high voltage grids. Additionally, a
simplified lumped parameters circuit model of the voltage transformer is proposed
and verified by simulation and experimental research.
In Chapter 4 a transistor LCC resonant DC/DC converter of electrical energy is
studied, working at frequencies higher than the resonant one. It is analyzed due to the
possible operating modes of the converter with accounting the influence of the
damping capacitors and the parameters of the matching transformer, drawing the
boundary curves between the different operating modes of the converter in the plane
of the output characteristics, as well as outlining the area of natural commutation of
the controllable switches. Finally, a laboratory prototype of the converter under
consideration is built after suggesting a methodology for designing it. Chapter 5
investigates the thermal behaviour of the power semiconductor as a component part of
the power converter (rectifier or inverter), and not as an isolated part, from different
structures of power rectifiers. To do this, the parametric simulations for the transient
thermal conditions of some typical power rectifiers are presented and the 3D thermal
modelling and simulations of a power device as main component of power converters
are described too.
Chapter 6 discusses the principle and control method of a Unified Power Quality
Conditioner (UPQC), mainly used in low-voltage low-capacity applications and effective
in reducing both harmonic voltage and harmonic current, but applied in this case to high
power nonlinear loads. In this UPQC, a shunt Active Power Filter (APF) is connected to
a series LC resonance circuit in grid fundamental frequency so as to make a shunt APF in
lower voltage and lower power, and uses a hybrid APF which includes a Passive Power
Filter (PPF). Chapter 7 summarizes the research of parallel and series resonances and
unifies the study providing a similar expression to the series resonance case, but
substantially improved for the parallel resonance case, and unique to their location. It is
completed with the analysis of the impact of the Steinmetz circuit inductor resistance on
the resonance and a sensitivity analysis of all variables involved in the location of the
parallel and series resonance. Finally, the chapter ends with several experimental tests to
validate the proposed expression and several examples of its application. Chapter 8