Voltage sag waveform features extraction using matlab

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FFATURES EXTRACTION USING MATLAB

I

'ARiDAH

HANI!*! BINT! MOHD NOH

P E R P U S T A K A A N U T H M

UNIVERSITI TUN HUSSEIN ONN MALAYSIA

BORANG PENGESAHAN STATUS TESIS

JUDUL : VOLTAGE SAG WAVEFORM FEATURES EXTRACTION USING

MATLAB

SESI PENGAJIAN: 2007 / 2008

Saya F ARID AH HANIM B I N T I M O H D NOH

( HURUF BESAR )

mengaku membenarkan tesis ( PSM / Sarjana / Doktor falsafah )* ini disimpan di Perpustakaan dengan syarat-syarat kegunaan seperti berikut:

1. Tesis ini hakmilik Kolej Universiti Teknologi Tun Hussein Onn. 2. Perpustakaan dibenarkan membuat salinan untuk tujuan pengajian sahaja

3. Perpustakaan dibenarkan membuat salinan tesis ini sebagai bahan pertukaran antara institusi pengajian tinggi.

4. ** Sila tandakan ( V )

SULIT

TERHAD

( Mengandungi maklumat yang berdaijah keselamatan atau kepentingan Malaysia yang termaktub di dalam AKTA RAHSIA RASMI 1972 )

( Mengandungi maklumat TERHAD yang telah ditentukan oleh organisasi / badan dimana penyelidikan dijalankan

V

( TANDATANGAN PENULIS )

Alamat Tetap :

No 14, Jin 32/10

Taman Koperasi Polis Fasa 2,

Batu Caves, K.L.

Disahkan oleh

G|AN PENYELIA )

PROF. MADYA. DR. ZAINAL ALAM BIN HARON

Nama Penyelia

Tarikh : 24 APRIL 2008 Tarikh: 24 APRIL 2008

CAT AT AN : * Potong yang tidak berkenaan.

** Jika tesis ini SULIT atau T E R H A D , sila lampirkan sural daripada pihak berkuasa/organisasi berkenaan dengan menyatakan sekali sebab dan tempoh tesis ini perlu dikelaskan sebagai SULIT atau TERHAD.

"I hereby acknowledge that I have read this report and I find that its contents meet the requirements in terms of scope and quality for the award of Master of Electrical

Engineering with Honours."

Signature of Supervisor

Name of Supervisor

Date

VOLTAGE SAG WAVEFORM FEATURES EXTRACTION USING MATLAB

t ARID AH HANIM BINTI MOHD NOH

A project report submitted in partial fulfillment of the Requirements for the award of Master of Electritkl feilgitieferiHg

Faculty of Electrical and Electronic Engineering

Universiti Tun Hussein Onn Malaysia

I dcclare that this report on "Voltage Sag Waveform Features Extraction Using Matlab" is the result of my own research except for works which have been cited in the references. The report lias not been accepted any degree and not concurrently submitted

in candidature ofany other degree.

Signature

Name of Author : FAR1DAH HAN1M B1NT1 MOHD NOH

iii

iv

ACKNOWLEDGEMENT

First of allr thanks to "Allah" for the continuous blessing and for giving me

the strength and chances in completing this project.

I wish to express my deepest gratitude to my project supervisor, Associate Prof. Dr. Zainal Alam Bin Haron, for his guidance, support and helpful comments in doing this project.

My family deserves special mention for their constant support during the project. Special thanks go to my dearest husband and daughter for being the driving force towards the success of my project.

To all of my friends who always helping me when is needed, thanks for everything.

XV

ABSTRACT

v i

ABSTRAK

vii

TABLE OF CONTENTS

CHAPTER TITLE PAGE

DECLARATION ii

DEDICATION iii

ACKNOWLEDGEMENT iv

ABSTRACT v

ABSTRAK vi

TABLE OF CONTENTS vii

LIST OF TABLES xi

LIST OF FIGURES xiii

LIST OF ABBREVIATIONS xvi

LIST OF SYMBOLS xvii

LIST OF APPENDICES xviii

1 INTRODUCTION 1

1.1 Proj ect Background 1 1.2 Problem Statement 4

1.3 Objectives 4 1.4 Scope of the Project 5

1.5 Significance of the Study 6

2 LITERATURE REVIEW 7

viii

Quality

2.2 Voltage Sag - A Brief Definition 11

2.2.1 Sources of Sag If 2.2.2 Voltage Sag in Power Quality 12

Classification

2.2.3 IEEE Standard Classification 15 for Voltage sag

2.3 Voltage Sag Detection 17 2.3.1 Triggering 17

2.3.1.1 Changes in rms or 19 Waveforms

2.3.2 Segmentation 20 2.3.2.1 Segmentation Based on 22

Time Dependent rms Sequences

2.4 Voltage Sag Characterization 24 2.4.1 Available Standards 24

2.4.1.1 IEEE Standard for 25 Voltage Sag

2.4.1.2IEC Standard for 25 Voltage Sag

2.4.1.3 Industry standards SEMI 25

2.4.2 Magnitude versus Time 27 2.4.3Phase Angle versus Time 30

2.4.4 Energy and Severity 32 2.4.4.1 Voltage Sag Energy 32

2.4.4.2 Voltage Sag Severity 33 2.4.5 Three-Phase Characteristics versus 34 Time

2.4.5.1 The Symmetrical 35 Component Classification

2.5 The Previous Research 40

3 METHODOLOGY 42

ix

3.2 Software Design and Development 43 3.2.1 Program Code Development 44

3.2.1.L Magnitude -RMS Voltage 45 Sequence

3.2.1.2 Duration-Triggering using 46 RMS Voltage Sequence

3.2.1.3 Phase Angle Jump Using 47 Discrete Fourier Transform

3.2.1.4 Energy and Severity 48 3.2.1.5 Segmentation- Time 49 dependent RMS sequence

3.2.1.6 Three Phase Unbalanced Sag 49 Classification

3.2.2 Graphical User Interface Design 50 and Development

3.3 Analysis on Validity of the Results 52

4 RESULT AND ANALYSIS 54

4.1 Result 54 4.1.1 Result on Single Phase Analysis Part 55

4.1.1.1 Magnitude and Duration 55 4.1.1.2 Phase Angle Jump of 60 Voltage Sag

4.1.1.3 Energy and Severity 63 4.1.2 Results on Three Phase Analysis Part 64

4.1.2.1 Segmentation Using Fundamental 65 or rms Sequence

4.1.2.2 Result for Type of Voltage Sag, 67 PN Factor and Characteristic Voltage

4.2 Analysis on Result 70 4.2.1 Single Phase Analysis Part 70

XV

4.2.2Three Phase Analysis Part 86

5 CONCLUSIONS 87

5.1 Conclusions 87

52 Further Work: 89

REFERENCES 90

x i

LIST OF TABLES

TABLE NO. TITLE PAGE

2.1 Different between power quality events 13 and variations

2.2 Categories and Characteristics of Power 13 System Electromagnetic Phenomena

2.3 Power quality events and variations 14

2.4 Methods in triggering 18 2.5 Complex voltages for three phase 38

unbalanced sag

2.6 The symmetrical component for three phase 39 unbalanced sags

3.1 Characteristic parameters and methods used 45 in the project

4.1 Magnitude and duration of voltage sag and 57 swell for wavel .xls

4.2 Magnitude and duration of voltage sag and swell 58 for wave4.xls

Xll

for wave5.xls

4.4 Phase angle jump of voltage sag and voltage 60 swell for wavel.xls

4.5 Phase angle jump of voltage sag and voltage 61 swell for wave4.xls

4.6 Phase angle jump of voltage sag and voltage 62 swell for wave5.xls

4.7 Energy for voltage sag or voltage swell 63

4.8 Severity of voltage sag 63 4.9 Type of voltage sag, characteristic voltage 69

and PN factor

4.10 Magnitude from the software and rms block set 73 simulation for wavel .xls

4.11 Magnitude from the software and rms block set 75 simulation for wave4.xls

4.12 Magnitude from the software and rms block 77 set simulation for wave5.xls

4.13 Phase angle jump from software and block set 79 simulation for wave4.xls

4.14 Phase angle jumps from software and block set 80 simulation for wavel .xls

4.15 Phase angle jumps from software and block set 82 simulation for wave5.xls

4.16 Manual calculation for energy and severity from 83 file wavel.xls

4.17 Comparison between the measured and calculated 83 value of sag energy and severity for wavel .xls

4.18 Manual calculation for energy and severity from 84 file wave4.xls

4.19 Comparison between the measured and calculated 84 value of sag energy and severity for wave4.xls

4.20 Manual calculation for energy and severity 85 from file wave5.xls

xiii

LIST OF FIGURES

FIGURE NO. TITLE PAGE

2.1 General scheme of power quality measurements 9 2.2 Role of signal processing in extraction of 10

information from power quality data

2.3 Voltage sag phenomenon due to short 12 circuit fault

2.4 IEEE 1159 subdivision of magnitude-duration 15 plane for classification of event

2.5 Instantaneous Voltage Sag 16 2.6 Voltage dip due to single-phase faults 18

2.7 The rms sequence and the predicted 20 underlying time events

2.8 Segmentation on sequence data 21 2.9 Required Semiconductor equipment 26

voltage-sag ride through capability curve

2.10 Rms voltage sequences for one cycle window 28 2.11 Phase angle of complex voltage in stationary 31

frame and rotating frame

2.12 Balanced voltage sag 34 2.13 Unbalanced three phase voltage sag 34

xiv

2.12 Balanced voltage sag 34 2.13 Unbalanced three phase voltage sag 34

2.14 Four types of three-phase unbalanced voltage 36 sag in phasor- diagram form.

3.1 Project operational framework 42 3.2 Software development 43 3.3 General flowchart of voltage sag features 44

extraction software

3.5 Sag's and swell's duration time 47 3.4 Main window for Voltage Sag Features 51

Extraction Software

3.5 Layout of the GUIs for sub-window 52 3.6 Block diagram for rms voltage simulation 53 3.7 Block diagram for fundamental component 53

voltage simulation

4.1 Rms voltage for each phases in wavel .xls 56 4.2 Rms voltage for each phases in wave4.xls 57 4.3 Rms voltage for each phases in wave5.xls 58 4.4 The phase angle shift in rotating frame 60

for wavel .xls

4 J The phase angle shift in rotating frame 61 for wave4.xls

4.6 The phase angle shift in rotating frame 62 for wave5.xls

4.7 Measures of changes in phase A, phase B 65 and phase C

4.8 The overall measures of changes in the 66 rms voltages

4.9 The segmentation area 66 4.10 The segmentation area for lower threshold value 67

4.11 The result for three phase unbalance sag 68 4.12 The three phase rms voltage for sample 71

file wavel .xls

X V

waveform file wavel .xls

4.14 The three phase rms voltage for sampled 73 waveform file wave4.xls

4.15 Rms voltage for each phase in sampled 74 waveform files wavel.xls

4.16 The three phase rms voltage for sampled 75 waveform file wave5.xls

4.17 Rms voltage for each phase in sampled 76 waveform files wave5.xls

4.18 Phase angle jump at phase ab, phase be 78 and phase ca for wave4.xls

4.19 Phase angle jump at phase a, phase b 79 and phase c for wavel.xls

xvi

LIST OF ABBREVIATIONS

PN - Positive Negative

TEEE - Institutes of Electrical and Electronics Engineers GUIDE - Graphical user interface development environment IEC - International Electrotechnical Comission

rms - Root mean square

CBEMA - Computer Business Equipment Manufacturers Association

SEMI - Semiconductor Equipment and Materials International THD - Total Harmonic Distortion

xvii

LIST OF SYMBOLS

V(t) - Voltage or current sample N - Size of sliding window U rms - rms Voltage

U fund - Fundamental voltage component V fund - Fundamental voltage component E dip - Energy

U nom - Nominal Voltage

f o - Power system frequency T - Duration

V - Residual voltage of sag S e - Severity

fs . Sampling frequency

f system - Frequency of power system

e - Exponential cp - Phase angle

Vj - Positive sequence voltage

V2 - Negative sequence voltage V0 - Zero sequence voltage

F - PN factor

xviii

LIST OF APPENDICES

APPENDIX TITLE PAGE

1

CHAPTER 1

INTRODUCTION

1.1 Project Background

Power quality is a term which broadly refers to maintaining near sinusoidal waveform of power distribution bus voltage at rated voltage and frequency [1], or in other words, providing a clean sinusoidal waveform without any power disturbances. Power quality problems or disturbances generally appear in the form of voltage sags, swells, harmonics, flickers and voltage imbalance. Since a large portion of power supply systems experiences a voltage sag whenever a fault occurs, voltage sags are much more common than actual interruptions in the power system network, but yet they are least avoidable power quality problem faced by utilities all over the world [2], Voltage sag can be defined as the reduction of the rms voltage to a value below a given threshold for duration between 0.5 cycles to 1 minute [3] [4].

2

applications utilize the sensitive electronics circuitry and microprocessors. The industries are now relying more and more on the automated equipment. Voltage sag may reset controllers and the controlled process may take significant time to restart again. In semiconductor device fabrication, a reset in the process will cause a significant loss in terms of productivity, time and material [2], For many other industrial users, a single voltage sag can cause losses equal to that caused by a power supply interruption [3]. Ironically, research carried out by [5] shows that the number of severe sags per year is higher than the number of interruptions per year. Due to this fact, voltage sag has become a major concern to industries worldwide.

Many engineering efforts [27] [28], researches [1] [23] and studies [26] [5], have been done on voltage sags. Basically, the study on voltage sags can be classified into the following categories:

1. Characterization and detection of voltage sag. 2. Equipment immunity.

3. Stochastic assessment. 4. Mitigation.

These four categories of studies are quite dependent on each other. But most of the times, all these studies are needed to solve a specific voltage sag problem [25]. The basic platform of other voltage sag studies is the characterization of the voltage sag. This study aim at acquiring knowledge of the voltage sags characteristics. Both fault propagation studies and measured data are being used for this. Voltage sag is normally characterized by its magnitude and duration. But some researches have shown that other parameters such as phase angle jump, point on wave, waveform distortion and phase imbalance could also affect the performance of some sensitive equipments.