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"With special relation to smart grids, this book provides clear and comprehensive explanation of how Digital Signal Processing (DSP) and Computational Intelligence (CI) techniques can be applied to solve problems in the power system.Its unique coverage bridges the gap between DSP, electrical power and energy engineering systems, showing many different techniques applied to typical and expected system conditions with practical power system examples.Surveying all recent advances on DSP for power systems, this book enables engineers and researchers to understand the current state of the art and to develop new tools. It presents: an overview on the power system and electric signals, with description of the basic concepts of DSP commonly found in power system problems the application of several signal processing tools to problems, looking at power signal estimation and decomposition, pattern recognition techniques, detection of the power system signal variations description of DSP in relation to measurements, power quality, monitoring, protection and control, and wide area monitoring a companion website with real signal data, several Matlab codes with examples, DSP scripts and samples of signals for further processing, understanding and analysis Practicing power systems engineers and utility engineers will find this book invaluable, as will researchers of electrical power and energy systems, postgraduate electrical engineering students, and staff at utility companies"--
List of contents
About the Authors xiii
Preface xv
AccompanyingWebsite xxi
Acknowledgments xxiii
1 Introduction 1
1.1 Introduction 1
1.2 The Future Grid 2
1.3 Motivation and Objectives 3
1.4 Signal Processing Framework 4
1.5 Conclusions 8
References 10
2 Power Systems and Signal Processing 11
2.1 Introduction 11
2.2 Dynamic Overvoltage 12
2.2.1 Sustained Overvoltage 12
2.2.2 Lightning Surge 13
2.2.3 Switching Surges 15
2.2.4 Switching of Capacitor Banks 17
2.3 Fault Current and DC Component 21
2.4 Voltage Sags and Voltage Swells 25
2.5 Voltage Fluctuations 27
2.6 Voltage and Current Imbalance 29
2.7 Harmonics and Interharmonics 29
2.8 Inrush Current in Power Transformers 42
2.9 Over-Excitation of Transformers 45
2.10 Transients in Instrument Transformers 47
2.10.1 Current Transformer (CT) Saturation (Protection Services) 47
2.10.2 Capacitive Voltage Transformer (CVT) Transients 54
2.11 Ferroresonance 55
2.12 Frequency Variation 56
2.13 Other Kinds of Phenomena and their Signals 56
2.14 Conclusions 57
References 58
3 Transducers and Acquisition Systems 59
3.1 Introduction 59
3.2 Voltage Transformers (VTs) 60
3.3 Capacitor Voltage Transformers 64
3.4 Current Transformers 67
3.5 Non-Conventional Transducers 71
3.5.1 Resistive Voltage Divider 71
3.5.2 Optical Voltage Transducer 72
3.5.3 Rogowski Coil 73
3.5.4 Optical Current Transducer 74
3.6 Analog-to-Digital Conversion Processing 75
3.6.1 Supervision and Control 78
3.6.2 Protection 79
3.6.3 Power Quality 79
3.7 Mathematical Model for Noise 80
3.8 Sampling and the Anti-Aliasing Filtering 81
3.9 Sampling Rate for Power System Application 84
3.10 Smart-Grid Context and Conclusions 84
References 85
4 Discrete Transforms 87
4.1 Introduction 87
4.2 Representation of Periodic Signals using Fourier Series 87
4.2.1 Computation of Series Coefficients 90
4.2.2 The Exponential Fourier Series 92
4.2.3 Relationship between the Exponential and Trigonometric oefficients 93
4.2.4 Harmonics in Power Systems 95
4.2.5 Proprieties of a Fourier Series 97
4.3 A Fourier Transform 98
4.3.1 Introduction and Examples 98
4.3.2 Fourier Transform Properties 103
4.4 The Sampling Theorem 104
4.5 The Discrete-Time Fourier Transform 108
4.5.1 DTFT Pairs 109
4.5.2 Properties of DTFT 110
4.6 The Discrete Fourier Transform (DFT) 110
4.6.1 Sampling the Fourier Transform 116
4.6.2 Discrete Fourier Transform Theorems 116
4.7 Recursive DFT 117
4.8 Filtering Interpretation of DFT 120
4.8.1 Frequency Response of DFT Filter 123
4.8.2 Asynchronous Sampling 124
4.9 The z-Transform 126
4.9.1 Rational z-Transforms 128
4.9.2 Stability of Rational Transfer Function 131
4.9.3 Some Common z-Transform Pairs 131
4.9.4 z-Transform Properties 133
4.10 Conclusions 133
References 133
5 Basic Power Systems Signal Processing 135
5.1 Introduction 135
5.2 Linear and Time-Invariant Systems 135
5.2.1 Frequency Response of LTI System 138
5.2.2 Linear Phase FIR Filter 140
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