VOUM- $ka mmmii FFATURES EXTRACTION USING MATLAB

Transcription

1 VOUM- $ka mmmii FFATURES EXTRACTION USING MATLAB I'ARiDAH HANI!*! BINT! MOHD NOH U^iVi-RSIT! TOM HUSSEIN OWN MALAYSIA

2 PERPUSTAKAAN UTHM * * a/no 153

3 UNIVERSITI TUN HUSSEIN ONN MALAYSIA BORANG PENGESAHAN STATUS TESIS 4 JUDUL : VOLTAGE SAG WAVEFORM FEATURES EXTRACTION USING MATLAB SESI PENGAJIAN: 2007 / 2008 Saya F ARID AH HANIM BINTIMOHD 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 TIDAK TERHAD Disahkan oleh Alamat Tetap : ( TANDATANGAN PENULIS ) G AN PENYELIA ) No 14, Jin 32/10 Taman Koperasi Polis Fasa 2, Batu Caves, K.L. 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 TERHAD, sila lampirkan sural daripada pihak berkuasa/organisasi berkenaan dengan menyatakan sekali sebab dan tempoh tesis ini perlu dikelaskan sebagai SULIT atau TERHAD. Tesis dimaksudkan sebagai tesis Ijazah Doktor Falsafah dan Saijana secara penyelidikan, atau disertasi bagi pengajian secara kerja kursus dan penyelidikan, atau Laporan projek Sarjana Muda (PSM).

4 "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 Prof. Madya Dr. Zainal Alam Bin Haron Date

5 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 APRIL 2008

6 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 Date : 24 APRIL 2008

7 iii To my beloved husband, Muhamad Faizal bin Yaakub and to my dearest daughter, NurAmnah Fasiliah

8 iv ACKNOWLEDGEMENT First of all r 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. My sincere appreciation also goes to everyone whom I may not have mentioned above who have helped directly or indirectly in the completion of my project.

9 XV ABSTRACT In this project a software tool to extract characteristic parameters from a voltage sag waveform has been successfully developed and tested. The real recorded voltage sag waveform was acquired from IEEE Working Group PI Power Quality Event Characterisation webpage. The development of this software tool was done using Matlab environment. Theories and methods on voltage sag characterization was studied and analyzed. The characteristic parameters extraction is done on two conditions of sag, which are voltage sag in single phase condition and voltage in for three phase condition. Two signal processing methods have been applied in order to extract the characteristic of voltage sag in these two conditions. The applied methods are the rms sequence and Discrete Fourier Transform. The extracted parameters or indices of voltage sag in this project are the sag's magnitude, duration, phase angle jump, energy, and severity, type of sag, PN factor and the characteristic voltage. These parameters are the indices which characterize the voltage sag in single phase and three phase condition. The values of these parameters are displayed in the Graphical User Interface of the software tool that has been developed. These values has been compared with the results obtain from the manual calculation and from the simulation results on the Matlab rms and Discrete Fourier block set.

10 vi ABSTRAK Satu perisian khas untuk mengekstrak parameter ciri-ciri lendut voltan daripada bentuk gelombang lendut voltan telah berjaya dibina dan diuji di dalam projek ini. Rakaman data bentuk gelombang lendut voltan sebenar telah diambil dari laman web Kumpulan Pencirian Gangguan Kualiti Kuasa IEEE Pembangunan perisian ini dibuat dalam persekitaran Matlab. Teori-teori dan kaedah untuk pencirian lendut voltan telah dikaji dan dianalisis. Parameter ciri-ciri lendut voltan diekstrak dalam dua keadaan, iaitu parameter lendut voltan satu fasa dan parameter lendut voltan tiga fasa. Dua kaedah pemprosesan signal digunakan untuk pengektrakan parameterparameter ini. Kaedah pemprosesan yang digunakan ialah jujukan rms dan jelmaan Fourier diskret. Parameter atau indeks lendut voltan yang diekstrak di dalam projek ini adalah magnitud, tempoh, anjakan sudut fasa, tenaga, keterukan, jenis lendut voltan, faktor PN dan voltan ciri. Kesemua parameter ini adalah indeks yang mencirikan lendut voltan satu fasa dan lendut voltan tiga fasa. Nilai kesemua parameter ini dipaparkan pada perantara pengguna grafik bagi perisian yang telah dibina dalam projek ini. Kesemua nilai ini kemudiannya dibandingkan dengan nilai yang diperolehi melalui pengiraan manual dan melalui simulasi set blok rms dan diskret Fourier Matlab.

11 vii TABLE OF CONTENTS CHAPTER TITLE PAGE DECLARATION DEDICATION ACKNOWLEDGEMENT ABSTRACT ABSTRAK TABLE OF CONTENTS LIST OF TABLES LIST OF FIGURES LIST OF ABBREVIATIONS LIST OF SYMBOLS LIST OF APPENDICES ii iii iv v vi vii xi xiii xvi xvii xviii 1 INTRODUCTION Proj ect Background Problem Statement Objectives Scope of the Project Significance of the Study 6 2 LITERATURE REVIEW Definition of Power Quality Power Quality Monitoring Signal Processing and Power 10

12 viii Quality 2.2 Voltage Sag - A Brief Definition Sources of Sag If Voltage Sag in Power Quality 12 Classification IEEE Standard Classification 15 for Voltage sag 2.3 Voltage Sag Detection Triggering Changes in rms or 19 Waveforms Segmentation Segmentation Based on 22 Time Dependent rms Sequences 2.4 Voltage Sag Characterization Available Standards IEEE Standard for 25 Voltage Sag IEC Standard for 25 Voltage Sag Industry standards SEMI Magnitude versus Time Phase Angle versus Time Energy and Severity Voltage Sag Energy Voltage Sag Severity Three-Phase Characteristics versus 34 Time The Symmetrical 35 Component Classification 2.5 The Previous Research 40 3 METHODOLOGY Proj ect Methodology 42

13 ix 3.2 Software Design and Development Program Code Development L Magnitude -RMS Voltage 45 Sequence Duration-Triggering using 46 RMS Voltage Sequence Phase Angle Jump Using 47 Discrete Fourier Transform Energy and Severity Segmentation- Time 49 dependent RMS sequence Three Phase Unbalanced Sag 49 Classification Graphical User Interface Design 50 and Development 3.3 Analysis on Validity of the Results 52 4 RESULT AND ANALYSIS Result Result on Single Phase Analysis Part Magnitude and Duration Phase Angle Jump of 60 Voltage Sag Energy and Severity Results on Three Phase Analysis Part Segmentation Using Fundamental 65 or rms Sequence Result for Type of Voltage Sag, 67 PN Factor and Characteristic Voltage 4.2 Analysis on Result Single Phase Analysis Part Magnitude Phase Angle Jump Energy and Severity 82

14 XV 4.2.2Three Phase Analysis Part 86 5 CONCLUSIONS Conclusions Further Work: 89 REFERENCES 90 Appendices A - B 94

15 xi 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 Methods in triggering 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 4.3 Magnitude and duration of voltage sag and swell 59

16 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 Severity of voltage sag 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 4.21 Comparison between the measured and calculated 85

17 xiii LIST OF FIGURES FIGURE NO. TITLE PAGE 2.1 General scheme of power quality measurements 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 Voltage dip due to single-phase faults The rms sequence and the predicted 20 underlying time events 2.8 Segmentation on sequence data Required Semiconductor equipment 26 voltage-sag ride through capability curve 2.10 Rms voltage sequences for one cycle window Phase angle of complex voltage in stationary 31 frame and rotating frame 2.12 Balanced voltage sag Unbalanced three phase voltage sag Four types of three-phase unbalanced voltage 36 sag in phasor- diagram form.

18 xiv 2.12 Balanced voltage sag Unbalanced three phase voltage sag Four types of three-phase unbalanced voltage 36 sag in phasor- diagram form. 3.1 Project operational framework Software development General flowchart of voltage sag features 44 extraction software 3.5 Sag's and swell's duration time Main window for Voltage Sag Features 51 Extraction Software 3.5 Layout of the GUIs for sub-window Block diagram for rms voltage simulation Block diagram for fundamental component 53 voltage simulation 4.1 Rms voltage for each phases in wavel.xls Rms voltage for each phases in wave4.xls Rms voltage for each phases in wave5.xls 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 The segmentation area for lower threshold value The result for three phase unbalance sag The three phase rms voltage for sample 71 file wavel.xls 4.13 Rms voltage for each phase in sampled 72

19 XV 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 4.20 Phase angle jump at phase ab, phase be 81 and phase ca for wave5.xls

20 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 FFT - Fast Fourier Transform DFT - Discrete Fourier Transform GUI - Graphical User Interface

21 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 f s. Sampling frequency f system - Frequency of power system e - Exponential cp - Phase angle Vj - Positive sequence voltage V 2 - Negative sequence voltage V 0 - Zero sequence voltage F - PN factor V - Characteristic voltage

22 xviii LIST OF APPENDICES APPENDIX TITLE PAGE A. The Layout of the Graphical User Interface 94 B. The Results of Three Phase Analysis 99

23 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]. Recent years, utilities have been faced with rising numbers of complaints about voltage sags [2]. This is because more loads are sensitive to voltage sag today rather than they were just a few years ago. Many

24 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. Many researchers are characterizing and detecting voltage sags by using the latest signal processing algorithm such as [6], [7] had proposed