Optical Sensing in Power Transformers
Description
Optical Sensing in Power Transformers is filled with the critical information and knowledge on the optical techniques applied in power transformers, which are important and expensive components in the electric power system. Effective monitoring of systems has proven to decrease the transformer lifecycle cost and increase a high level of availability and reliability. It is commonly held that optical sensing techniques will play an increasingly significant role in online monitoring of power transformers.
In this comprehensive text, the authors--noted experts on the topic--present a scholarly review of the various cutting-edge optical principles and methodologies adopted for online monitoring of power transformers. Grounded in the authors' extensive research, the book examines optical techniques and high-voltage equipment testing and provides the foundation for further application, prototype, and manufacturing. The book explores the principles, installation, operation, condition detection, monitoring, and fault diagnosis of power transformers. This important text:
* Provides a current exploration of optical sensing application in power transformers
* Examines the critical balance and pros and cons of cost and quality of various optical condition monitoring techniques
* Presents a wide selection of techniques with appropriate technical background
* Extends the vision of condition monitoring testing and analysis
* Treats condition monitoring testing and analysis tools together in a coherent framework
Written for researchers, technical research and development personnel, manufacturers, and frontline engineers, Optical Sensing in Power Transformers offers an up-to-date review of the most recent developments of optical sensing application in power transformers.
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Persons
JUN JIANG, PHD, is Associate Professor, Department of Electrical Engineering, Nanjing University of Aeronautics and Astronautics, China.
GUOMING MA, PHD, is Professor, State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, China.
Content
Foreword ix
Preface xi
Acknowledgments xiii
About the Authors xv
Acronyms xvii
List of Figures xxi
List of Tables xxix
1 Power Transformer in a Power Grid 1
1.1 Typical Structure of a Power Transformer 2
1.2 Insulation Oil in a Power Transformer 3
1.3 Condition Monitoring of an Oil-Immersed Power Transformer 7
1.3.1 Temperature 7
1.3.2 Moisture 8
1.3.3 Dissolved Gases Analysis 9
1.3.4 Partial Discharge 10
1.3.5 Combined Online Monitoring 11
1.4 Conclusion 11
References 12
2 Temperature Detection with Optical Methods 15
2.1 Thermal Analysis in a Power Transformer 15
2.1.1 Heat Source in a Power Transformer 15
2.1.2 Heat Transfer in a Power Transformer 16
2.2 Fluorescence-Based Temperature Detection 18
2.2.1 Detection Principle 18
2.2.2 Fabrication and Application 20
2.2.3 Merits and Drawbacks 21
2.3 FBG-Based Temperature Detection 22
2.3.1 Detection Principle 22
2.3.2 Fabrication and Application 24
2.3.3 Merits and Drawbacks 25
2.4 Distribution Measurement 27
2.4.1 Quasi-Distributed Temperature Sensing 27
2.4.2 Distribute Temperature Sensing 28
2.4.2.1 Light Scattering 28
2.4.2.2 Raman Based Distributed Temperature Sensing 28
2.4.2.3 Rayleigh-Based Distributed Temperature Sensing 32
2.4.3 Merits and Drawbacks 33
2.5 Conclusion 33
References 34
3 Moisture Detection with Optical Methods 37
3.1 Online Monitoring of Moisture in a Transformer 37
3.1.1 Distribution of Moisture in the Power Transformer 38
3.1.2 Typical Moisture Detection Techniques 40
3.2 FBG-Based Moisture Detection 42
3.2.1 Detection Principle 42
3.2.2 Fabrication and Application 45
3.2.3 Merits and Drawbacks 48
3.3 Evanescent Wave-Based Moisture Detection 49
3.3.1 Detection Principle 49
3.3.2 Fabrication of MNF 53
3.3.2.1 Chemical Etching Method 53
3.3.2.2 Fused Biconical Taper Method 54
3.3.3 MNF Moisture Detection 56
3.3.4 Merits and Drawbacks 57
3.4 Fabry-Perot-Based Moisture Detection 58
3.4.1 Detection Principle 58
3.4.2 Fabrication and Application 59
3.4.3 Merits and Drawbacks 61
3.5 Conclusion 61
References 62
4 Dissolved Gases Detection with Optical Methods 65
4.1 Online Dissolved Gases Analysis 65
4.1.1 General Quantitive Requirements of Online DGA 67
4.1.2 Advantages of Optical Techniques in DGA 70
4.2 Photoacoustic Spectrum Technique 70
4.2.1 Detection Principle of PAS 70
4.2.2 Application of a PAS-Based Technique 73
4.2.3 Merits and Drawbacks 74
4.3 Fourier Transform Infrared Spectroscopy (FTIR) Technique 76
4.3.1 Detection Principle of FTIR 76
4.3.2 Application of the FTIR-Based Techniques 80
4.3.2.1 FTIR Technique 80
4.3.2.2 Online FTIR Application 85
4.3.2.3 Combination of FTIR and PAS 86
4.3.3 Merits and Drawbacks 88
4.4 TDLAS-Based Technique 89
4.4.1 Detection Principle of TDLAS 89
4.4.2 Application of the TDLAS-Based Technique 92
4.4.2.1 Optical Lasers 94
4.4.2.2 Multi-pass Gas Cell 95
4.4.2.3 Topology of Multi-gas Detection 96
4.4.2.4 Laboratory Tests 99
4.4.2.5 Field Application 103
4.4.3 Merits and Drawbacks 105
4.5 Laser Raman Spectroscopy Technique 106
4.5.1 Detection Principle of Raman Spectroscopy 106
4.5.2 Application of Laser Raman Spectroscopy 107
4.5.3 Merits and Drawbacks 109
4.6 Fiber Bragg Grating (FBG) Technique 110
4.6.1 Detection Principle of FBG 110
4.6.2 Application of the FBG Technique 110
4.6.2.1 Standard FBG Sensor 110
4.6.2.2 Etched FBG Sensor 114
4.6.2.3 Side-Polished FBG Sensor 118
4.6.3 Merits and Drawbacks 121
4.7 Discussion and Prediction 123
4.7.1 Comparison of Optical Fiber Techniques 123
4.7.2 Future Prospects of Optic-Based Diagnosis 125
4.8 Conclusions 127
References 128
5 Partial Discharge Detection with Optical Methods 137
5.1 PD Activities in Power Transformers 137
5.1.1 Online PD Detection Techniques 138
5.1.2 PD Induced Acoustic Emission 139
5.2 FBG-Based Detection 142
5.2.1 FBG PD Detection Principle 142
5.2.2 PS-FBG PD Detection 144
5.2.3 High Resolution FBG PD Detection 148
5.2.4 Merits and Drawbacks 149
5.3 FP-Based PD Detection 150
5.3.1 FP-Based Principle 150
5.3.2 Application of FP PD Detection 152
5.3.3 Sensitivity of an FP-Based Sensor 155
5.3.3.1 The Diaphragm Thickness 155
5.3.3.2 The Diaphragm Material 156
5.3.3.3 The Diaphragm Shape 156
5.3.4 Merits and Drawbacks 157
5.4 Dual-Beam Interference-Based PD Detection 158
5.4.1 Principle of Different Interference Structures 158
5.4.1.1 Mach-Zehnder Interference 158
5.4.1.2 Michelson Interference 159
5.4.1.3 Sagnac Interference 160
5.4.2 Application Cases 162
5.4.2.1 PD Detection Based on Mach-Zehnder 162
5.4.2.2 PD Detection Based on Michelson 162
5.4.2.3 PD Detection Based on Sagnac 163
5.4.3 Sensitivity of an Interference-Based Sensor 166
5.4.3.1 Sensor Parameter Variation 166
5.4.3.2 Phase Modulation and Demodulation Techniques 168
5.4.4 Merits and Drawbacks 171
5.5 Multiplexing Technology of an Optical Sensor 171
5.5.1 Multiplexing Technique with the Same Structure 171
5.5.2 Multiplexing Technique with the Different Structures 175
5.5.3 Distributed Optical Sensing Technique 176
5.6 Conclusion 179
References 182
6 Other Parameters with Optical Methods 189
6.1 Winding Deformation and Vibration Detection in Optical Techniques 189
6.1.1 Winding Deformation Detection 189
6.1.1.1 Winding Deformation in Power Transformer 189
6.1.1.2 Winding Deformation Detection with an Optical Technique 190
6.1.2 Vibration Detection 192
6.1.2.1 Vibration in Power Transformers 192
6.1.2.2 Vibration Detection with Optical Techniques 194
6.1.3 Merits and Drawbacks 197
6.2 Voltage and Current Measurement with Optical Techniques 198
6.2.1 Current Measurement with Optical Technique 199
6.2.1.1 Principle of Optical Current Transducer 199
6.2.1.2 All-Fiber Optical Current Transducer 200
6.2.2 Voltage Measurement with the Optical Technique 200
6.2.2.1 Principle of the Optical Voltage Transducer 200
6.2.2.2 All-Fiber Optical Voltage Transducer 202
6.2.3 Merits and Drawbacks 202
6.3 Electric Field Measurement 203
6.4 Conclusion 205
6.5 Outlook 207
6.5.1 Profound and Extensive Interdisciplinary Combinations 208
6.5.2 Mature Scheme and Low Cost Manufacturing 208
6.5.3 Reliable Measurement and Long-Term Stability 208
6.5.4 Pre-factory Installation and Integration into a Monitoring System 209
6.5.5 Rapid Expansion and Development 209
6.5.6 Advanced Algorithms and Novel Diagnosis 210
References 210
Index 213
Acronyms
A.U. Arbitrary unit AC Alternating current AE Acoustic emission AI Artificial intelligence ANSI American National Standards Institute AOCT All-fiber optical current transformer AOVT All-fiber type optical voltage transformer APD Avalanche photodiode ASTM American Society for Testing and Materials BDV Breakdown voltage B-OTDA Brillouin optical time-domain analysis B-OTDR Brillouin optical time-domain reflectometry BSO Bismuth silicon oxide CBM Condition-based maintenance CNT Carbon nanotube CT Current transducers CW Continuous wave DAQ Data acquisition DC Direct current DCM Differential cross-multiplication DGA Dissolved gas analysis DP Degree of polymerization DTM Duval triangle method DTS Distributed temperature sensing EFBG Etched FBG EFPI Extrinsic Fabry-Perot interferometer EM Electromagnetic EMI Electromagnetic interference ESA Electrical spectrum analyzer ESDD Equivalent salt deposit density FBG Fiber Bragg grating FDS Frequency domain dielectric spectroscopy FEA Finite element analysis FEP Fluorinated ethylene propylene FE-SEM Field emission scanning electron microscope FET Field effect transistor FIB Focused ion beam FID Flame ionization detectors FLCEAS Frequency-locking cavity enhanced absorption spectroscopy FOSs Fiber optic sensors FP Fabry-Perot FPI Fabry-Perot interferometer FRA Frequency response analysis FRM Faraday rotating mirror FTIR Fourier transform infrared spectroscopy FWHM Full width at half maximum GC Gas chromatography GIS Gas insulated switchgear GMM Gaussian mixture model HFCT High frequency current transformer HITRAN High-resolution transmission molecular absorption database HST Hottest spot temperature HVDC High voltage direct current IEC International Electrotechnical Commission IEEE Institute of Electrical and Electronic Engineers IFFT Inverse fast Fourier transform IFPI Intrinsic Fabry-Perot interferometer IR Infrared spectroscopy ISAM Ionic self-assembly monolayer KDP Potassium dihydrogen phosphate KFT Karl-Fischer titration LCSET Lowest cold start energizing temperatures LD Laser diode LED Light emitting diode LOD Limitation-of-detection LPGs Long period gratings LRS Laser Raman spectroscopy LTC Load tap changer MCU Micro control unit MEMS Micro electro machining system MFC Mass flow controller MIR Mid-infrared MMI Multimode interference MNF Micro/nano fiber M-Z Mach-Zehnder NDIR Non-dispersive infrared NIR Near-infrared NPs Nanoparticles OCT Optical current transducer OFAF Oil forced air forced type OFAN Oil forced air natural type OFGs Optical fiber gratings OFWF Oil forced water forced ONAF Oil natural air forced type ONAN Oil natural air natural type ONWF Oil natural water forced OSP Optical sensor probe OVT Optical voltage transducers PA Peak area PAS Photoacoustic spectroscopy Pd Palladium PD Partial discharge PD Photodiode/photodetector PDC Polarization depolarization current PDIV Inception voltage of partial discharge PET Polyethylene glycol ester PGC Phase generation carrier PI Polyimide PID Proportion integration differentiation PM Planned maintenance PMMA Polymethyl methacrylate PNNL Pacific Northwest National Laboratory PPV Peak-to-peak voltage PRPD Phase-resolved partial discharge PS-FBG Phase-shifted FBG PTFE Polytetrafluoroethylene PVA Polyvinyl acrylate PZT Piezoelectric transducer QCL Quantum cascade laser QEO Quadratic electro-optic QEPAS Quartz-enhanced photoacoustic spectroscopy QTF Quartz tuning fork RAM Residual amplitude modulation RH Relative humidity RI Refractive index R-OTDR Raman optical time-domain reflectometry RS Raman spectroscopy SDM Space division multiplexing SERS Surface-enhanced Raman scattering SHM Structural health monitoring SMF Single-mode fiber SNR Signal-to-noise ratio SP Side-polished SP-FBG side-polished FBG TCD Thermal conductivity detectors TDCG Total dissolved combustible gas TDLAS Tunable diode laser absorption spectrum TDM Time division multiplexing TEC Thermoelectric TF Time...
