Power Quality Monitoring Analysis and Enhancement Part 1 potx

Used under license from Shutterstock.com First published August, 2011 Printed in Croatia A free online edition of this book is available at www.intechopen.com Additional hard copies can

POWER QUALITY – MONITORING, ANALYSIS

AND ENHANCEMENT

Edited by Ahmed Faheem Zobaa,

Mario Mañana Canteli and Ramesh Bansal

Power Quality – Monitoring, Analysis and Enhancement

Edited by Ahmed Faheem Zobaa, Mario Mañana Canteli and Ramesh Bansal

Published by InTech

Janeza Trdine 9, 51000 Rijeka, Croatia

Copyright © 2011 InTech

All chapters are Open Access articles distributed under the Creative Commons

Non Commercial Share Alike Attribution 3.0 license, which permits to copy,

distribute, transmit, and adapt the work in any medium, so long as the original

work is properly cited After this work has been published by InTech, authors

have the right to republish it, in whole or part, in any publication of which they

are the author, and to make other personal use of the work Any republication,

referencing or personal use of the work must explicitly identify the original source Statements and opinions expressed in the chapters are these of the individual contributors and not necessarily those of the editors or publisher No responsibility is accepted for the accuracy of information contained in the published articles The publisher assumes no responsibility for any damage or injury to persons or property arising out

of the use of any materials, instructions, methods or ideas contained in the book

Publishing Process Manager Sandra Bakić

Technical Editor Teodora Smiljanic

Cover Designer Jan Hyrat

Image Copyright Sergej Razvodovskij, 2010 Used under license from Shutterstock.com

First published August, 2011

Printed in Croatia

A free online edition of this book is available at www.intechopen.com

Additional hard copies can be obtained from orders@intechweb.org

Power Quality – Monitoring, Analysis and Enhancement,

Edited by Ahmed Faheem Zobaa, Mario Mañana Canteli and Ramesh Bansal

p cm

ISBN 978-953-307-330-9

Contents

Preface IX

Part 1 Power Quality Monitoring, Classification,

Measurements, and Analysis 1

Chapter 1 Power Quality Monitoring 3

Kazem Mazlumi Chapter 2 Wavelet and PCA to Power Quality

Disturbance Classification Applying a RBF Network 21

Giovani G Pozzebon, Ricardo Q Machado, Natanael R Gomes, Luciane N Canha and Alexandre Barin Chapter 3 Power Quality Measurement Under

Chapter 5 Application of Signal Processing in

Power Quality Monitoring 77

Zahra Moravej, Mohammad Pazoki and Ali Akbar Abdoos Chapter 6 Methodes of Power Quality Analysis 101

Gabriel Găşpăresc Chapter 7 Pre-Processing Tools and Intelligent Systems Applied to

Power Quality Analysis 119

Ricardo A S Fernandes, Ricardo A L Rabêlo, Daniel Barbosa, Mário Oleskovicz and Ivan Nunes da Silva

VI Contents

Chapter 8 Selection of Voltage Referential from the Power Quality and

Apparent Power Points of View 137

Helmo K Morales Paredes, Sigmar M Deckmann, Luis C Pereira da Silva and Fernando P Marafão Chapter 9 Single-Point Methods for Location of Distortion,

Unbalance, Voltage Fluctuation and Dips Sources

Zhengyou He and Yong Jia

Part 2 Power Quality Enhancement and Reactive

Power Compensation and Voltage Sag Mitigation of Disturbances 217

Chapter 11 Active Load Balancing in a Three-Phase Network by Reactive

Power Compensation 219 Adrian Pană

Chapter 12 Compensation of Reactive Power and Sag Voltage Using

Superconducting Magnetic Energy Storage System 255 Mohammad Reza Alizadeh Pahlavani

Chapter 13 Optimal Location and Control of Flexible Three Phase

Shunt FACTS to Enhance Power Quality in Unbalanced Electrical Network 281

Belkacem Mahdad

Chapter 14 Performance of Modification of a Three Phase Dynamic

Voltage Restorer (DVR) for Voltage Quality Improvement in Electrical Distribution System 305

R Omar, N.A Rahim and Marizan Sulaiman

Chapter 15 Voltage Sag Mitigation by Network Reconfiguration 325

Nesrallh Salman, Azah Mohamed and Hussain Shareef

Chapter 16 Intelligent Techniques and Evolutionary Algorithms

for Power Quality Enhancement in Electric Power Distribution Systems 345

S Prabhakar Karthikeyan, K Sathish Kumar,

I Jacob Raglend and D.P Kothari

Preface

Power quality has become an important issue in recent times when many utilities around the world find very difficult to meet energy demands which leads to load shedding and power quality problems This book on power quality written by experts

in their fields will be of great benefit to professionals, engineers and researchers This book comprises of 16 chapters which are arranged in two sections Section one covers power quality monitoring, classification, and analysis aspects Power quality enhancement, reactive power compensation and voltage sag mitigation of disturbances in transmission and distribution system are presented in the second section Brief discussion of each chapter is as follows

Chapter 1 presents the monitoring of voltage sags to find its origin and detect types of sags The calculations of various types of faults which may cause voltage sags have been discussed Optimal placement of voltage sag monitors has also been discussed in the chapter

Chapter 2 proposes the applications of discrete wavelet transform (DWT), principal component analysis (PCA) and artificial neural networks (ANN) in order to classify power quality disturbances The method proposes to analyse seven classes of signals, namely Sinusoidal Waveform, Capacitor Switching Transient, Flicker, Harmonics, Interruption, Notching and Sag, which is composed of four main stages: (1) signal analysis using the DWT; (2) feature extraction; (3) data reduction using PCA; (4) classification using a radial basis function network (RBF) The MRA (Multiresolution Analysis) technique of DWT is employed to extract the discriminating features of distorted signals at different resolution levels Subsequently, the PCA is used to condense information of a correlated set of variables into a few variables, and a RBF network is employed to classify the disturbance types

Chapter 3 presents a critical review of apparent power, reactive power and power factor definitions These definitions are reviewed for single phase and three phase systems and are evaluated under different conditions such as sinusoidal, non sinusoidal, one phase, and balanced and unbalanced three phase systems Then, a methodology to measure power and power quality indexes based on the instant power theory under non sinusoidal conditions is presented

X Preface

Chapter 4 deals with the application of power quality monitoring in power system network comprising of distributed energy sources (DER) The importance to integrate power quality analysis functions into protection relay has been described The voltage and current transducers for measurement of line voltage and current signals have been discussed

Chapter 5 discusses the applications of signal processing techniques for power quality monitoring This chapter also presents various classification techniques which are very useful for power system disturbances, e.g ANN, support vector machines (SVM), pattern recognition, etc Filter and Wrapper based methods used for removal of irreverent and redundant data and feature selection are discussed

Chapter 6 presents different methods for the power quality analysis A comparative analysis of Discrete Fourier Transform (DFT), Short-Time Fourier Transform (STFT), Discrete Wavelet Transform (DWT) and Discrete Stockwell Transform (DST) is presented for power quality analysis

Chapter 7 presents a review of various preprocessing (DWT, Shannon entropy, signal energy, and fractal dimension) and intelligent techniques (ANN, adaptive Neural-Fuzzy Interface Systems (ANFIS), and Neural-Genetic) used for power quality analysis This chapter also demonstrates the application of ATP (alternative transients program) software preprocessing and disturbance analysis of real distribution system Chapter 8 presents the selection of the voltage referential (reference point) which can influence the total harmonic distortion, unbalance factors, voltage sags and swells in three-phase system The definition of apparent power is reviewed using voltage referential A methodology based on Blakesley’s theorem is presented in order to allow the association of the most common voltage measurement approaches in such a way that the power quality and power components definitions are not be improperly influenced

Chapter 9 deals with problems of location of the disturbance source based on the measurements made at a single point of a network (PCC) Methodologies are presented for high harmonics, voltage fluctuations, voltage dips and unbalance that allow the determination of location of the disturbance source at the supplier side (upstream) or at the customer side (downstream) viewed from PCC

Chapter 10 discusses the theoretical background on STFT, wave transform (WT) and transform The indices which are most frequently used in international standards and four new power quality indices for transient disturbances based on S-transform are defined The performance of the new power quality indices is evaluated using mathematical and PSCAD/EMTDC simulated disturbance signals

S-Chapter 11 presents detailed analysis of active load balancing in a three phase system using reactive power compensation This chapter develops a mathematical model associated to the circuit proposed by Steinmetz which is commonly used in major

industrial applications Sizing the compensator elements on the criterion of reactive power demand from network is discussed

Chapter 12 presents a novel and optimized switching strategy and control approach for a three level two-quadrant chopper in a three-level neutral point clamped (NPC) voltage source inverter (VSI) superconducting magnetic energy storage(SMES) Using the proposed switching strategy, the voltage of the inverter capacitors in SMES can be independently controlled and minimum power and switching losses can be achieved using this same strategy In addition, this chapter proposes a new algorithm for SMES

to compensate the voltage sag in the power networks Simulation results show that the VSI SMES, when combined with the proposed algorithm, is able to compensate the voltage sag and phase voltage in less than one cycle, which is five times better than other voltage sag compensators

Chapter 13 presents optimal placement and control of FACTS devices and discusses

a methodology that coordinates the expertise of power system engineer formulated

in flexible fuzzy rules to dynamically adjust the reactive power compensation based

on three phase model of shunt FACTS controller (SVC) installed at critical buses The main target of the proposed technique is to reduce the asymmetrical voltage and

to enhance the system loadability with consideration of unbalanced electrical network

Chapter 14 presents a novel topology of the dynamic voltage restorer (DVR) with split capacitors and new installation of the capacitors filtering scheme using a three phase four wire, three phase inverter with six Insulated Gate Bipolar Transistor (IGBTs) Experimental and simulation results show the advantages of proposed DVR over traditional DVRs

Chapter 15 presents an overview on utility efforts in voltage sag mitigation employing the network reconfiguration strategy The theoretical background of the proposed method is first introduced and then the analysis and simulation tests on a practical system are described to highlight the suitability of network reconfiguration as a method for voltage sag mitigation The analyses of simulation results suggest significant findings which can assist utility engineers to take the right decision in network reconfiguration

Chapter 16 presents the applications of artificial intelligence techniques for power quality enhancement in distribution system The proposed approach is tested on a 75 bus practical system using fuzzy adaptive evolutionary computing

Editors are grateful to many people who have contributed to this book In particular Editors would like to thank all authors for their contributions Editors are indebted to all the reviewers for reviewing the book chapters which has improved the quality of the book Editors would like to thank the authorities and staff members of and The University of Queensland, University of Cantabria and Brunel University who have

XII Preface

been very generous and helpful in maintaining a cordial atmosphere and extending all the facilities required for the book Thanks are due to InTech - Open Access Publisher, especially to Ms Sandra Bakic Publishing Process Manager for making sincere efforts

in timely bringing out the book Editors would like to express thanks and sincere regards to their family members who have provided great support for completion of this book

Ahmed Faheem Zobaa

Brunel University, Uxbridge,

U.K

Mario Mañana Canteli

University of Cantabria (UC), Santander,

Spain

Ramesh Bansal

The University of Queensland,

Australia

Part 1

Power Quality Monitoring, Classification, Measurements, and Analysis

There are several reasons for monitoring power quality The most important reason is the economic damage produced by electromagnetic phenomena in critical process loads Effects

on equipment and process operations can include malfunctions, damage, process disruption, and other anomalies

It is noted that monitoring, alone, is not the solution for power quality problems In order to solve the power quality problems, some other remedies more than the installation of power quality monitors are needed In fact, monitoring provides the essential data which are needed for the improvement of power quality In many projects related to finding a solution for power quality problems, monitoring plays a decisive role, and, therefore, managing monitoring properly helps to minimize the cost of solving problems

The recorded power quality data depends on the way the instruments record the disturbance levels and how the signals are interpreted In order to have a correct interpretation of the recorded data, users need to know the specifications of the monitoring instruments such as sampling rate, accuracy, resolution, anti-aliasing filter The mis-interpretation may result in non-existent errors and recording disturbances which in turn may lead to incorrect conclusions and costly decisions

Effective monitoring programs are important for power reliability assurance for both utilities and customers It is worth pointing out that most customer power quality problems originate within the customer facility Monitoring power quality ensures optimal power system performance and effective energy management Voltage sags, harmonics, interruptions, high-frequency noise, etc., are the most important power quality problems which are seen in industrial and commercial installations Troubleshooting these problems requires measuring and analyzing power quality and that leads to the importance of monitoring instruments in order to localize the problems and find solutions Although the