Computational Paradigm Techniques for Enhancing Electric Power Quality Computational Paradigm Techniques for Enhancing Electric Power Quality L Ashok Kumar S Albert Alexander MATLAB ® and Simulink® are trademarks of The MathWorks, Inc and are used with permission The MathWorks does not warrant the accuracy of the text or exercises in this book This book’s use or discussion of MATLAB ® and Simulink® software or related products does not constitute endorsement or sponsorship by The MathWorks of a particular pedagogical approach or particular use of the MATLAB ® and Simulink® software CRC Press Taylor & Francis Group 6000 Broken Sound Parkway NW, Suite 300 Boca Raton, FL 33487-2742 © 2019 by Taylor & Francis Group, LLC CRC Press is an imprint of Taylor & Francis Group, an Informa business No claim to original U.S Government works Printed on acid-free paper International Standard Book Number-13: 978-1-138-33699-5 (Hardback) This book contains information obtained from authentic and highly 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access www.copyright.com (http://www copyright.com/) or contact the Copyright Clearance Center, Inc (CCC), 222 Rosewood Drive, Danvers, MA 01923, 978-7508400 CCC is a not-for-profit organization that provides licenses and registration for a variety of users For organizations that have been granted a photocopy license by the CCC, a separate system of payment has been arranged Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identification and explanation without intent to infringe Library of Congress Cataloging‑in‑Publication Data Names: Kumar, L Ashok, author | Albert Alexander, S author Title: Computational paradigm techniques for enhancing electric power quality / L Ashok Kumar and S Albert Alexander Description: First edition | New York, NY : CRC Press/Taylor & Francis Group, 2019 | Includes bibliographical references and index Identifiers: LCCN 2018033182 | ISBN 9781138336995 (hardback : acid-free paper) | ISBN 9780429442711 (ebook) Subjects: LCSH: Electric power production Quality control Data processing Classification: LCC TK1010 K86 2019 | DDC 621.31/042 dc23 LC record available at https://lccn.loc.gov/2018033182 Visit the Taylor & Francis Web site at http://www.taylorandfrancis.com and the CRC Press Web site at http://www.crcpress.com Contents Preface xv Acknowledgments xvii Authors xix Abbreviations xxi Introduction 1.1 General Classes of Power Quality Problems 1.2 Types of Power Quality Problems Voltage Sags (Dips) 1.2.1 1.2.2 Voltage Swells 1.2.3 Long-Duration Overvoltages 1.2.4 Undervoltages 1.2.5 Interruptions 1.2.6 Transients 1.2.7 Voltage Unbalance 1.2.8 Voltage Fluctuations Harmonics 10 1.2.9 1.2.10 Electrical Noise .14 1.2.11 Transient Overvoltage 15 1.2.11.1 Capacitor Switching 15 1.2.11.2 Magnification of Capacitor-Switching Transients 16 1.2.11.3 Restrikes during Capacitor Deenergizing 18 1.2.12 Lightning 20 1.2.13 Ferroresonance 22 1.3 Principles of Overvoltage Protection 27 1.3.1 Devices for Overvoltage Protection 29 Surge Arresters and Transient Voltage Surge Suppressors 29 1.3.1.1 1.3.1.2 Isolation Transformers 30 Low-Pass Filters 31 1.3.1.3 1.3.1.4 Low-Impedance Power Conditioners 31 Utility Surge Arresters 32 1.3.1.5 1.3.2 Utility Capacitor-Switching Transients 34 1.3.2.1 Switching Times 34 1.3.2.2 Pre-insertion Resistors 34 1.3.2.3 Synchronous Closing 36 Capacitor Location 39 1.3.2.4 1.3.2.5 Utility System Lightning Protection 39 1.3.2.6 Shielding 40 Line Arresters 40 1.3.2.7 1.4 Origin of Short Interruptions 41 1.4.1 Terminology 41 1.4.1.1 Interruption 41 1.4.1.2 Sags (Dips) 42 1.4.1.3 Swells 44 v vi Contents 1.5 1.6 Monitoring of Short Interruptions 44 1.5.1 Sag 44 1.5.2 Swell 45 1.5.3 Influence of Equipment 45 1.5.3.1 Single Phase Tripping 45 1.5.3.2 Benefits of Single-Pole Tripping 46 1.5.3.3 Single-Pole Tripping Concerns and Solutions 46 Description of Long-Duration Power Quality Issues 53 1.6.1 Transients 53 1.6.2 Short-Duration Voltage Variations 53 1.6.3 Long-Duration Voltage Variations 53 1.6.4 Voltage Unbalance 53 1.6.5 Waveform Distortion 53 1.6.6 Voltage Fluctuations 53 1.6.7 Power Frequency Variations 54 Mitigation Techniques 55 2.1 Introduction 55 2.1.1 Series Controllers 56 2.1.2 Shunt Controllers—STATCOM 56 2.1.3 Combined Shunt and Series Controllers 57 2.1.3.1 Unified Power Flow Controller 57 2.1.3.2 Interline Power Flow Controller 57 2.2 Application of FACTS Controllers in Distribution Systems 57 2.3 Introduction to Long-Duration Voltage Variations 58 2.3.1 Observation of System Performance 58 2.3.2 Principle of Regulating Voltage 58 2.4 Devices for Voltage Regulation 59 2.4.1 Electronic Voltage Regulator 59 Zener-Controlled Transistor Voltage Regulator 59 2.4.2 2.4.3 Zener-Controlled Transistor Series Voltage Regulator 59 2.4.3.1 Operation 60 2.4.3.2 Limitations 60 2.4.4 Zener-Controlled Transistor Shunt Voltage Regulator 60 2.4.4.1 Operation 60 2.4.4.2 Limitations 61 2.4.5 Discrete Transistor Voltage Regulator 61 2.4.5.1 Limitations of Transistor Voltage Regulators 62 2.4.6 Electromechanical Regulator 63 2.4.7 Automatic Voltage Regulator 63 2.4.8 Constant Voltage Transformer 63 2.4.9 Utility Voltage Regulator Application 63 2.5 Step-Voltage Regulator Basic Operation 64 2.5.1 Voltage Regulator Applications 66 2.5.2 Voltage Regulator Sizing and Connection 66 2.5.3 Capacitor Selection Is Key to Good Voltage Regulator Design 67 2.5.4 Dealing with EMI 67 2.5.5 The L-C Output Filter 69 Seeking Guidance 70 2.5.6 2.5.7 A Critical Part of Power Supply Design 71 2.5.8 End-User Capacitor Application 71 2.5.9 Energy Storage Device 71 2.5.10 Pulsed Power and Weapons 72 Contents vii 2.5.11 Power Conditioning 72 2.5.12 Power Factor Correction 72 2.5.13 Motor Starters 72 2.5.14 Signal Processing 73 2.5.15 Tuned Circuits 73 2.5.16 Regulating Utility Voltage with Distributed Resources 73 2.5.17 Flicker 74 2.5.17.1 Standards and Regulation 75 2.6 Introduction to Voltage Sag 76 2.6.1 Voltage Sag 76 2.6.2 Voltage Sag Magnitude 77 2.6.3 Voltage Sag Duration 78 2.6.3.1 Three-Phase Unbalance 80 2.6.3.2 Phase Angle Jumps 80 2.6.3.3 Magnitude and Phase-Angle Jumps for Three-Phase Unbalanced Sags 81 2.6.3.4 Other Characteristics of Voltage Sags 83 2.6.3.5 Load Influence on Voltage Sags 83 2.6.4 Equipment Behavior 84 2.6.4.1 Voltage-Tolerance Curves 84 Voltage-Tolerance Tests 84 2.6.4.2 2.6.5 Computers and Consumer Electronics 86 Estimation of Computer Voltage Tolerance 86 2.6.5.1 2.6.6 Adjustable AC Drive System 87 2.6.7 Adjustable DC Drives 88 2.6.7.1 Other Sensitive Loads 89 2.7 Stochastic Assessment of Voltage Sag 89 Compatibility between Equipment and Supply 89 2.7.1 2.7.1.1 Presentation of Results: Voltage Sag Co-ordination Chart 91 2.8 Mitigation of Voltage Sag 93 2.8.1 From the Fault to Trip 93 2.8.2 Reducing the Number of Faults 94 Reducing the Fault-Clearing Time 95 2.8.3 2.8.4 Including Changes in Power System 96 Installing Mitigation Equipment 97 2.8.5 2.8.6 Improvising Equipment Immunity 97 2.9 Different Events and Mitigation Methods 98 2.10 Voltage Imbalance and Voltage Fluctuation 98 2.10.1 Voltage Imbalance 98 2.10.2 Voltage Fluctuation 99 2.10.2.1 Causes of Voltage Fluctuations 99 2.10.2.2 Sources of Voltage Fluctuations 100 2.10.2.3 Mitigation of Voltage Fluctuations in Power Systems 100 2.10.3 Voltage Stabilization Solutions 101 2.11 Waveform Distortion 101 2.11.1 Power Frequency Variation 102 2.11.1.1 Variation from Rated Voltage 102 2.11.1.2 Variation from Rated Frequency 102 2.11.1.3 Combined Variation of Voltage and Frequency 102 2.11.1.4 Effects of Variation of Voltage and Frequency upon the Performance of Induction Motors 103 viii Contents 2.11.1.5 Operation of General-Purpose Alternating-Current Polyphase 2-, 4-, and 8-Pole, 60 Hz Integral-Horsepower Induction Motors Operated on 50 Hz 103 2.11.1.6 Effects of Voltages over 600 V on the Performance of Low-Voltage Motors 104 2.11.2 Electrical Noise 104 2.11.2.1 Internal Noise 104 2.11.2.2 External Noise 104 2.11.2.3 Frequency Analysis of Noise 108 2.11.3 Overvoltage and Undervoltage 110 2.11.3.1 Overvoltage 110 2.11.3.2 Lightning 112 2.11.3.3 Surges Induced by Equipment .112 2.11.3.4 Effects of Overvoltages on Power System .114 2.11.3.5 Undervoltage 114 2.11.3.6 Outage 115 2.11.4 Harmonics 115 2.11.4.1 Harmonic Number (h) 115 2.11.4.2 Harmonic Signatures 116 2.11.4.3 Effect of Harmonics on Power System Devices 116 Guidelines for Harmonic Voltage and Current Limitation 119 2.11.4.4 2.11.4.5 Harmonic Current Cancellation 120 Harmonic Filters 120 2.11.4.6 2.11.4.7 Cures for Low-Frequency Disturbances 121 2.11.4.8 Isolation Transformers 122 2.11.4.9 Voltage Regulators 122 2.11.4.10 Static Uninterruptible Power Source Systems 123 2.11.4.11 Rotary Uninterruptible Power Source Units 127 2.11.4.12 Voltage Tolerance Criteria 128 2.11.5 Harmonic Distortion 129 2.11.5.1 Total Harmonic Distortion 130 2.11.5.2 The Usual Suspects 131 Importance of Mitigating THD 131 2.11.5.3 2.11.5.4 Voltage vs Current Distortion .132 Current Measurement with Harmonics 132 2.11.5.5 2.11.5.6 Voltage Measurement with Harmonics 133 2.11.5.7 Effects of Current Distortion 133 2.11.5.8 Effects of Voltage Distortion 134 2.11.5.9 Harmonics vs Transients 134 2.11.5.10 Sources of Current Harmonics 134 2.11.5.11 Voltage and Current Harmonics 135 2.11.6 Harmonic Indices 135 2.11.6.1 Single Site Indices 135 2.11.6.2 System Indices 139 Harmonic Sources from Commercial Loads 143 2.11.6.3 2.11.7 Interharmonics 154 2.11.7.1 Description of the Phenomenon 154 A Voltage-Controlled DSTATCOM for Power Quality Improvement 163 3.1 Introduction 163 3.2 DSTATCOM .163 3.3 Design of DSTATCOM 165 Contents ix 3.4 Control Circuit Design and Reference Terminal Voltage Generation 166 3.5 Simulation 166 Power Quality Issues and Solutions in Renewable Energy Systems .173 4.1 Introduction .173 4.2 Power Quality in Electrical Systems 173 4.3 Solutions to Power Quality Problems��������������������������������������������������������������������������������174 4.4 Multilevel Inverters and Their Structures�������������������������������������������������������������������������175 4.4.1 Diode-Clamped Multilevel Inverter������������������������������������������������������������������176 4.4.2 Flying Capacitor Multilevel Inverter�����������������������������������������������������������������177 4.4.3 Cascaded H Bridge Multilevel Inverter (CHBMLI)�����������������������������������������178 4.4.4 Reduced Order Multilevel Inverter�������������������������������������������������������������������179 Comparison of Multilevel Inverters����������������������������������������������������������������� 180 4.4.5 4.4.6 Applications of Multilevel Inverters����������������������������������������������������������������� 180 4.4.7 Integration of MLI with Solar PV Systems������������������������������������������������������ 180 4.5 Power Quality Improvement Techniques for a Solar-Fed CMLI��������������������������������������182 4.5.1 Intelligent Techniques���������������������������������������������������������������������������������������182 4.5.2 Problem Statement���������������������������������������������������������������������������������������������183 4.6 Literature Review��������������������������������������������������������������������������������������������������������������183 4.7 Modeling of Solar Panel��������������������������������������������������������������������������������������������������� 184 Design Specifications���������������������������������������������������������������������������������������������������������188 4.8 4.9 Experimental Setup���������������������������������������������������������������������������������������������������������� 190 4.10 Selective Harmonic Elimination�������������������������������������������������������������������������������������� 193 4.10.1 Problem Statement�������������������������������������������������������������������������������������������� 194 4.10.2 Optimal Harmonic Stepped Waveform������������������������������������������������������������ 194 4.10.3 Artificial Neural Network�������������������������������������������������������������������������������� 199 4.10.4 Data Set Collection������������������������������������������������������������������������������������������� 199 4.10.5 ANN Architecture�������������������������������������������������������������������������������������������� 200 4.11 Optimization Techniques�������������������������������������������������������������������������������������������������� 201 4.11.1 Problem Formulation���������������������������������������������������������������������������������������� 201 4.11.2 Genetic Algorithm�������������������������������������������������������������������������������������������� 203 4.11.3 Computation of Switching Angles������������������������������������������������������������������� 203 4.11.3.1 Generation of Initial Chromosomes���������������������������������������������� 203 4.11.3.2 Population�������������������������������������������������������������������������������������� 203 4.11.3.3 Fitness Function����������������������������������������������������������������������������� 203 4.11.3.4 Crossover Operation���������������������������������������������������������������������� 204 4.11.3.5 Mutation Operation������������������������������������������������������������������������ 204 4.11.3.6 Termination������������������������������������������������������������������������������������ 204 4.11.4 Particle Swarm Optimization��������������������������������������������������������������������������� 204 4.11.5 Bees Optimization�������������������������������������������������������������������������������������������� 205 4.11.6 Natural World of Bees�������������������������������������������������������������������������������������� 206 4.11.7 Computation of Switching Angles������������������������������������������������������������������� 206 4.12 Simulation Results������������������������������������������������������������������������������������������������������������ 207 4.12.1 Optimal Harmonic Stepped Waveform������������������������������������������������������������ 207 4.12.2 Artificial Neural Networks������������������������������������������������������������������������������� 209 4.12.3 Optimization Techniques����������������������������������������������������������������������������������212 4.13 Experimental Results���������������������������������������������������������������������������������������������������������215 4.14 Lower Order Harmonics Mitigation in a PV Inverter�������������������������������������������������������219 4.14.1 Methodology����������������������������������������������������������������������������������������������������� 220 4.14.2 Origin of Lower Order Harmonics and Fundamental Current Control����������� 221 4.14.3 Origin of Lower Order Harmonics������������������������������������������������������������������� 221 4.14.3.1 Odd Harmonics������������������������������������������������������������������������������ 221 4.14.4 Even Harmonics����������������������������������������������������������������������������������������������� 221 440 Computational Paradigm Techniques for Enhancing Electric Power Quality 14.7 Simulation Results of VCIMD Figure 14.8 shows the output voltage waveform of the vector-controlled induction motor drive Figure 14.9 shows the three-phase output current waveform of the VCIMD, and the value of the current is nearly 150 A 14.8 Speed Waveform Figure 14.10 shows the speed waveform of the vector-controlled induction motor drive and the output is captured FIGURE 14.8 Output voltage waveform FIGURE 14.9 Output current waveform Power-Quality Improvements in Vector-Controlled Induction Motor Drives 441 FIGURE 14.10 Speed waveform 14.9 Torque Waveform Figure 14.11 shows the torque waveform of the vector-controlled induction motor drive and the range of values at one cycle is determined 14.10 6-Pulse Converter with VCIMD Figure 14.12 represents the MATLAB Simulink model of 6-pulse AC–DC converter fed with a vectorcontrolled induction motor, and here VCIMD acts as a load The output waveforms of the converter and the FFT analysis is done for the AC input mains current and the value of THD is displayed FIGURE 14.11 Torque waveform of VCIMD 442 Computational Paradigm Techniques for Enhancing Electric Power Quality FIGURE 14.12 Simulink model of 6-pulse converter Figure 14.13 shows the input source current waveform of a 6-pulse converter Figure 14.14 shows the THD analysis waveform of a 6-pulse converter, and the value of THD is 24.89% FIGURE 14.13 Input source current waveform Power-Quality Improvements in Vector-Controlled Induction Motor Drives 443 FIGURE 14.14 THD waveform for 6-pulse converter 14.11 12-Pulse Converter Figure 14.15 represents the MATLAB Simulink model of a 12-pulse AC–DC converter fed with a vector-controlled induction motor and here VCIMD acts as a load The output waveforms of the converter and the FFT analysis is done for the AC input mains current and the value of THD is displayed Figure 14.16 shows the THD analysis waveform of the 12-pulse converter is shown above and the value of THD is 14.40% Computational Paradigm Techniques for Enhancing Electric Power Quality FIGURE 14.15 Simulink model of 12-pulse converter 444 Power-Quality Improvements in Vector-Controlled Induction Motor Drives 445 FIGURE 14.16 THD waveform for 12-pulse converter 14.12 18-Pulse Converter Figure 14.17 represents the MATLAB Simulink model of an 18-pulse AC–DC converter fed with a vector-controlled induction motor and here VCIMD acts as a load The output waveforms of the converter and the FFT analysis is done for the AC input mains current and the value of THD is displayed Figure 14.18 shows the THD analysis waveform of a 12-pulse converter and the value of THD is 12.74% Computational Paradigm Techniques for Enhancing Electric Power Quality FIGURE 14.17 Simulink model of 18-pulse converter 446 Power-Quality Improvements in Vector-Controlled Induction Motor Drives 447 FIGURE 14.18 THD waveform for 18-pulse converter 14.13 24-Pulse Converter Figure 14.19 represents the MATLAB Simulink model of a 24-pulse AC–DC converter fed with a vectorcontrolled induction motor and here VCIMD acts as a load The output waveforms of the converter and the FFT analysis is done for the AC input mains current and the value of THD is displayed Figure 14.20 shows the THD analysis waveform of a 24-pulse converter and the value of THD is 9.38% 14.14 Results and Conclusion The performance of 6-pulse, 12-pulse, 18-pulse, and 24-pulse AC–DC converters for harmonic mitigation in vector-controlled induction motor drives are presented in this project The four types of AC–DC converter modeled in SIMULINK are extensively analyzed and the performance characteristics are observed The THD analysis result of the 6-pulse converter is to be found as 24.39%, the analysis result of the 12-pulse converter is to be calculated as 14.40%, the analysis THD result of the 18-pulse converter is shown as 12.74%, and the result of the 24-pulse converter is reduced to 9.38% The various converters are shown to overcome some of the problems associated with lower pulse rectifier By increasing the number of pulses, the harmonic values can be found to be improved Thus, this technique of harmonic mitigation of various converters with vector-controlled induction motor drives is extensively analyzed and its performance is observed Computational Paradigm Techniques for Enhancing Electric Power Quality FIGURE 14.19 Simulink model of 24-pulse converter 448 Power-Quality Improvements in Vector-Controlled Induction Motor Drives FIGURE 14.20 THD waveform for 24-pulse converter 449 Index AC controllers 163 AC drives 87, 296, 347 AC filter 163 AC Motor 87, 88, 116, 117, 378, 401 activation function 199, 200, 343 active filter 120, 121, 161, 233 active power line conditioners 233, 297, 298 active power quality conditioners 233 adaptive-based theory 344 adaptive filter 221, 223, 224, 225, 226 adaptive linear neuron 324, 347 A/D converter 221 adjustable speed drives 11, 34, 53, 76, 100, 116, 145, 382, 391, 417 angle control unit 304, 305 ant colony optimization 236 arc furnace 288, 322 arc welders 113, 145, 155 artificial neural networks 182, 200, 209 automatic voltage regulator 63 avalanche breakdown 76 back propagation 200, 332, 343 back propagation-based theory 343 band-pass damping 306 bandwidth 108, 192, 223, 264, 344, 345, 348 battery 191, 220, 273, 344 battery charger 135, 143, 148, 220, 389 battery energy storage system 273, 344 bees optimization 182, 205 bipolar switching 380 Boltzmann’s constant 185 boost converter 176, 181, 222, 295 bridge rectifier 264, 298, 311 brownouts buck converter 69, 220 bus bar 269, 270, 291 bus ways 118 cables 118 capacitor banks 118 capacitor location 16, 35, 39 capacitors 120, 143, 150 capacitor switching 3, 15 capacitor-switching transients 34 capacitor voltage 86 cascaded multilevel inverter 175, 178 choppers 295 chromosomes 203 circuit breakers 95, 112 clamping devices 29, 31 commercial loads 143 compensating signals 323 compensation coefficients 345 composite observer-based theory 344 conservative power theory 345 constant voltage transformer 63 consumer electronics 86, 298 continuous conduction mode 238, 295 control systems 354 converters 371, 382 crossover operation 204 cross vector theory 340 cumulative table 91 current-based compensation 337 current control 345 current density 185 curve-fitting method 371, 372 cycloconverter 154, 155, 417 DC drives 296 DC link capacitor 273, 291, 300, 312 DC offset 53 dead time 220 diode 68 diode bridge 436 diode-clamped multilevel inverter 176 direct current control 346 discontinuous conduction mode 238 discrete transistor voltage regulator 61 distributed generation 409 distribution systems 57 double data rate 216 drop out 129 DSTATCOM 163 duration 76 dynamic saturation 304 dynamic voltage restorer 97 eddy current losses 117 efficiency 143 electrical noise 14 electric arc furnaces 401 electric fields 185 electromagnetic fields electromagnetic pulses 76 electromechanical regulator 63 elevators 100 energy 129 energy storage 71 fast Fourier transform 338 fault-clearing time 94 faults 94 fault to trip 93 feeder ferroresonance 22 filter 287 451 452 firing angle 219 fitness function 203 flicker fluorescent lighting 105 flying capacitor 176 flying capacitor multilevel inverter 177 Fourier transform 216 frequency frequency domain 338 fuel cell 178 fuses fuzzy logic controller 182 Gauss−Newton algorithm 200 genetic algorithm 203 global theory 341 grid 178 grid-interconnected systems 409 grounding 246, 263 harmonic current 291 harmonic distortion harmonic filters 120 harmonic indices 135 harmonic isolator 291 harmonic number 115 harmonics harmonic signatures 116 HVAC 143 hybrid filter 277 hysteresis band 166 impedance 11 indirect current control 346 inductive spikes 76 instantaneous reactive power compensator 394 instantaneous symmetrical component theory 343 insulated-gate bipolar transistors 258 intelligent techniques 182 interharmonics 154 interruption 279 isolation transformers 30 jump, phase angle 80 Kalman filter 333 Kalman–Bucy filter 338 K-factor transformers 156 learning vector quantization 344 least mean square 221 least-squares fitting 371 lightning 30 lightning arresters 8, 22, 112 lightning strikes linear load 101 linear quadratic regulator 345 line arresters 40 line harmonics 377 load-commutated inverter 417 Index load conformity factors 345 locked-rotor current 104 long duration variation low-pass filters 31 magnetic fields 117 magnetizing current 147, 220 magneto motive force 244 magnitude 77 MathCAD 199 MATLAB 207 mitigation techniques 55 modified sine wave 378 modified square wave 378 modified unipolar switching 381 monocrystalline 186 motor starters 72 multilevel inverter 175 multiple component 269 mutation operation 204 neutral conductor 193, 234 neutral point-clamped 163, 175 Newton−Raphson 183 no load condition 160, 273 nonlinear load notching 1, 105 odd harmonics 221 open circuit 53, 187 optimal pulse-width modulation 184 oscillatory transients outage 115 overheating 11, 14, 26 overvoltages partial shading 181, 186 particle swarm optimization 204 passive filter 234 permanent magnet synchronous generator 344 phase angle jumps 80 phase coordinates 341 phase-locked loop 224 phase-lock technique 373 phase reference currents 373 phase sequence 89 phase shift 346 phasor 80 pole shift controller 345 polycrystalline 186 population 203 power power conditioning 72 power electronics 73 power factor 15, 16, 18, 53 power factor correction 72 power frequency variations power quality power quality analyzer 216 power system 234 453 Index PQR theory 336 PQSE 44 pre-insertion resistors 34 programmable pulse generator 207 protective devices 27 pulsed power 72 pure sine wave 379 pyranometer 188 quality quantity 80, 134 quantization 304, 344 reactive power 389 reactive power compensation 371 rectifier 157 regeneration 298 regulation 59 renewable energy systems 173 resonance 289, 291, 295 resonant current controllers 349 restrikes 18 reverse saturation current 186, 188 ripple factor 59, 60, 68 sag sag density table 91 saturable devices 145 scalar control 435 scatter diagram 91 Scott transformer 245 selective harmonic elimination 193 sensors 220, 221, 273 series inductance 266, 272 service factor 104 shielding 40 short circuit 13, 267, 289, 295, 351 short duration variations short interruptions 1, 41 shunt active filter 163, 233 shunt capacitor 165 signal conditioning 323 silicon-controlled rectifier 18 single line diagram 401 single-phase power supply 143 single phase tripping 45 single-pole tripping 46 skin depth 153 sliding mode control 236, 322 solar cell 178, 182, 185 solar insolation 185, 189 solar photovoltaics 74 space-vector modulation 351 speed 440 square wave inverter 378 standard inverter 298 standards 75 standard test conditions 185 star delta transformer 244, 248 star hexagon transformer 248 static compensators 163 steady-state tolerance 128 step up transformer 181, 220 step-voltage regulator 64 stochastic assessment 89 stopping criteria 213, 214 string 181 surge arresters surges 105, 110 swell switching frequency 181, 183 synchronous closing 18, 36 synchronous current detection 371 synchronous frame-based theory 343 synchronous motor drives 417 synchronous reference frame 236 synchronous reference frame theory 292 system indices 139 t-connected transformer 244 three phase four wire system 249 three-phase unbalance 80 thyristor 55 thyristor-controlled reactors 401 time domain 323 torque 417 transformers 116 transient impulsive transient overvoltage 15 transients 53 transmission system faults 78 tuned circuits 73 unbalanced 240 undervoltages unidirectional transients unipolar switching 380 unity power factor theory 343 universal bridge 403 UPFC 57 UPQC 234 utility surge arresters 32 utility voltage regulator 63 variable frequency drive 131, 292 varistors 27, 29 vector control 435 vectorial theory 341 voltage and current-based compensation 337 voltage-based compensation 337 voltage dips voltage flicker voltage fluctuations voltage imbalance voltage magnification 17 voltage notching 30 voltage regulation 59 voltage regulator 59 voltage sag co-ordination chart 91 voltage source inverter 382 454 voltage stabilization 101 voltage-tolerance curves 84 voltage-tolerance tests 84 waveform distortion 101 waveform reconstruction 345 wavelet transform 339 welding plants 100 wind turbine 74 Index Zener-controlled transistor series voltage regulator 59 Zener-controlled transistor shunt voltage regulator 60 Zener-controlled transistor voltage regulator 59 zero sequence 3, 44, 80 zero sequence current filter 271 zero-sequence fundamental current 233 zero-sequence harmonics 233 zigzag transformer 271 .. .Computational Paradigm Techniques for Enhancing Electric Power Quality Computational Paradigm Techniques for Enhancing Electric Power Quality L Ashok Kumar S Albert... Static VAR systems Computational Paradigm Techniques for Enhancing Electric Power Quality 1.2.1 Voltage Sags (Dips) IEEE Standard P1564 gives the recommended indices and procedures for characterizing... cause of power quality problems 1.2 Types of Power Quality Problems Defining and understanding the diverse power quality problems helps to prevent and solve those problems The type of power quality