Cover image for Electromagnetic transient analysis and novel protective relaying techniques for power transformer
Title:
Electromagnetic transient analysis and novel protective relaying techniques for power transformer
Personal Author:
Publication Information:
Singapore : John Wiley & Sons, Inc., 2015
Physical Description:
x, 326 pages : illustrations ; 25 cm.
ISBN:
9781118653821

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30000010344094 TK2861 L56 2015 Open Access Book Book
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Summary

Summary

An advanced level examination of the latest developments in power transformer protection

This book addresses the technical challenges of transformer malfunction analysis as well as protection. One of the current research directions is the malfunction mechanism analysis due to nonlinearity of transformer core and comprehensive countermeasures on improving the performance of transformer differential protection. Here, the authors summarize their research outcomes and present a set of recent research advances in the electromagnetic transient analysis, the application on power transformer protections, and present a more systematic investigation and review in this field. This research area is still progressing, especially with the fast development of Smart Grid. This book is an important addition to the literature and will enhance significant advancement in research. It is a good reference book for researchers in power transformer protection research and a good text book for graduate and undergraduate students in electrical engineering.

Chapter headings include : Transformer differential protection principle and existing problem analysis; Malfunction mechanism analysis due to nonlinearity of transformer core; Novel analysis tools on operating characteristics of Transformer differential protection; Novel magnetizing inrush identification schemes; Comprehensive countermeasures on improving the performance of transformer differential protection

An advanced level examination of the latest developments in power transformer protection Presents a new and systematic view of power transformer protection, enabling readers to design new models and consider fresher design approaches Offers a set of approaches to optimize the power system from a microeconomic point of view


Author Notes

Xiangning Lin , Professor, College of Electrical and Electronic Engineering, Huazhong University of Science and Technology, China.
Prof. Lin was the first to discover the ultra-saturation phenomenon of power transformer and he designed operating characteristics analysis planes to make clear the advantages and disadvantages of existing differential protection of power transformer. He invented a variety of novel protection algorithms for the main protection of the power transformer. A series of papers were published in journals including IEEE Transactions on Power Systems and IEEE Transactions on Power Delivery. The work has been widely acknowledged and cited by international peers. He also pioneers the introduction of modern signal processing techniques to design the protection criteria for power transformer. He was the winner of the 2nd Class National Natural Science Award in 2009. He has published nearly 200 papers and books (in Chinese), he also owns over 15 patents.

Jing Ma , Associate Professor, School of Electrical and Electronic Engineering, North China Electric Power University, Beijing, China.
Prof. Ma was the first to apply the two-terminal network algorithm to the areas of power system protection. The work has been widely acknowledged and cited by international peers. He also proposed an approach based on grille fractal to solve the TA saturation problem, and the related paper has been published in the IEEE Transactions on Power Delivery. The research results were used in many practical engineering projects.

Dr. Qing Tian , Senior Engineer with the Maintenance and Test Center of EHV Transmission Co. Ltd, Southern Power Grid, Guangzhou, China.

Dr. Hanli Weng , Senior Engineer with Three-Gorge Hydropower Plant, China Yangtze Power Co., Ltd.
Both have been working in this area since 1995. Their main research fields include power system operation analysis and control, voltage and reactive power optimization, power system reliability and risk assessment and power system energy saving assessment and planning.


Table of Contents

About the Authorsp. xi
Prefacep. xi
1 Principles of Transformer Differential Protection and Existing Problem Analysisp. 1
1.1 Introductionp. 1
1.2 Fundamentals of Transformer Differential Protectionp. 2
1.2.1 Transformer Faultsp. 2
1.2.2 Differential Protection of Transformersp. 3
1.2.3 The Unbalanced Current and Measures to Eliminate Its Effectp. 5
1.3 Some Problems with Power Transformer Main Protectionp. 7
1.3.1 Other Types of Power Transformer Differential Protectionsp. 7
1.3.2 Research on Novel Protection Principlesp. 9
1.4 Analysis of Electromagnetic Transients and Adaptability of Second Harmonic Restraint Based Differential Protection of a UHV Power Transformerp. 17
1.4.1 Modelling of the UHV Power Transformerp. 17
1.4.2 Simulation and Analysisp. 20
1.5 Study on Comparisons among Some Waveform Symmetry Principle Based Transformer Differential Protectionp. 27
1.5.1 The Comparison and Analysis of Several Kinds of Symmetrical Waveform Theoriesp. 27
1.5.2 The Theory of Waveform Symmetry of Derivatives of Current and Its Analysisp. 28
1.5.3 Principle and Analysis of the waveform Correlation Methodp. 32
1.5.4 Analysis of Reliability and Sensitivity of Several Criteriap. 33
1.6 Summaryp. 36
Referencesp. 36
2 Malfunction Mechanism Analysis due to Nonlinearity of Transformer Core
2.1 Introductionp. 39
2.2 The Ultra-Saturation Phenomenon of Loaded Transformer Energizing and its Impacts on Differential Protectionp. 43
2.2.1 Loaded Transformer Energizing Model Based Second Order Equivalent Circuitp. 43
2.2.2 Preliminary Simulation Studiesp. 48
2.3 Studies on the Unusual Mal-Operation of Transformer Differential Protection during the Nonlinear Load Switch-Inp. 57
2.3.1 Simulation Model of the Nonlinear Load Switch-Inp. 57
2.3.2 Simulation Results and Analysis of Mal-Operation Mechanism of Differential Protectionp. 62
2.4 Analysis of a Sort of Unusual Mal-operation of Transformer Differential Protection the Removal of External Faultp. 70
2.4.1 Modelling of the External Fault Inception and Removed and Current Transformerp. 70
2.4.2 Analysis of Low Current Mal-operation of Differential Protectionp. 72
2.5 Analysis and Countermeasure of Abnormal Operation Behaviours of the Differential Protection of the Converter Transformerp. 80
2.5.1 Recurrence and Analysis of the Reported Abnormal Operation of the Differential Protection of the Converter Transformerp. 80
2.5.2 Time-difference criterion to Discriminate between Faults and Magnetizing Inrushes of the Converter Transformerp. 86
2.6 Summaryp. 95
Referencesp. 95
3 Novel Analysis Tools on Operating Characteristics of Transformer Differential Protecionp. 97
3.1 Introductionp. 97
3.2 Studies on the Operation Behaviour of Differential Protection During a Loaded Transformer Energizingp. 99
3.2.1 Simulation Models of Loaded Transformer Switch-On and CTp. 99
3.2.2 Analysis of the Mal-operation Mechanism of Differential Protectionp. 102
3.3 Comparative Investigation on Current Differential Criteria between One Using Phase Current and One Using Phase-Phase Current Difference for the Transformer using Y-Delta Connectionp. 109
3.3.1 Analyses of Applying the Phase Current Differential to the Power Transformer with Y/¿ Connection and its Existing Basesp. 109
3.3.2 Rationality Analyses of Applying the Phase Current Differential Criterion to the Power Transformer with Y/¿ Connectionp. 113
3.4 Comparative Analysis on Current Percentage Differential Protections Using a Novel Reliability Evaluation Criterionp. 117
3.4.1 Introduction to CPD and NPDp. 117
3.4.2 Performance Comparison between CPD and NPD in the Case of CT Saturationp. 118
3.4.3 Performance Comparison between CPD and NPD in the Case of Internal Faultp. 121
3.5 Comparative Studies on Percentage Differential Criteria Using Phase Current and Superimposed Phase Currentp. 123
3.5.1 The Dynamic Locus of $$$ in the Case of CT Saturationp. 123
3.5.2 Sensitivety Comparison between the Phase Current Based and the Superimposed Current Based Differential Criteriap. 126
3.5.3 Security Comparison between the Phase Current Based and the Superimposed Current Based Differential Criteriap. 128
3.5.4 Simulation Analysesp. 130
3.6 A Novel Analysis Methodology of Differential Protection Operation Behaviourp. 132
3.6.1 The Relationship between Transforming Rate and the Angular Change Rate under CT Saturationp. 132
3.6.2 Principles of Novel Percentage Restraint Criteriap. 133
3.6.3 Analysis of Novel Percentage Differential Criteriap. 142
3.7 Summaryp. 151
Referencesp. 151
4 Novel Magnetizing Inrush Identification Schemep. 153
4.1 Introductionp. 153
4.2 Studies for Identification of the Inrush Based on Improved Correlation Algorithmp. 155
4.2.1 Basic Principle of Waveform Correlation Schemep. 155
4.2.2 Design and Test of the Improved Waveform Correlation Principlep. 159
4.3 A Novel Method for Discrimination of Internal Faults and Inrush Currents by Using Waveform Singularity Factorp. 163
4.3.1 Waveform Singularity Factor Based Algorithmp. 163
4.3.2 Testing Results and Analysisp. 163
4.4 A New Principle of Discrimination between Inrush Current and Internal Fault Current of Transformer Based on Self-Correlation Functionp. 169
4.4.1 Basic Principle of Correlation Function Applied to Random Single Analysisp. 169
4.4.2 Theory and Analysis of Waveform Similarity Based on Self-Correlation Functionp. 170
4.4.3 EPDL Testing Results and Analysisp. 173
4.5 Identifying Inrush Current Using Sinusoidal Proximity Factorp. 174
4.5.1 Sinusoidal Proximity Factor Based Algorithm|o174
4.5.2 Testing Results and Analysisp. 176
4.6 A Wavelet Transform Based Scheme for Power Transformer Inrush Identificationp. 181
4.6.1 Principle of Wavelet Transformp. 181
4.6.2 Inrush Identification with WPTp. 181
4.6.3 Result and Analysisp. 185
4.7 A Novel Adaptive Scheme of Discrimination between Internal Faults and Inrush Currents of Transformer Using Mathematical Morphologyp. 190
4.7.1 Mathematical Morphologyp. 190
4.7.2 Principle and Scheme Designp. 193
4.7.3 Testing Results and Analysisp. 194
4.8 Identifying Tranformer Inrush Current Based on Normalized Grille Curvep. 202
4.8.1 Normalized Grille Curvep. 202
4.8.2 Experimental Systemp. 205
4.8.3 Testing Results and Analysisp. 207
4.9 A Novel Algorithm for Discrimination between Inrush Currents and Internal Faults Based on Equivalent Instantaneous Leakage Inductancep. 211
4.9.1 Basic Principlep. 211
4.9.2 EILI-Based Criterionp. 217
4.9.3 Experimental Results and Analysisp. 218
4.10 A Two-Terminal Network-Based Method for Discrimination between Internal Faults and Inrush Currentsp. 222
4.10.1 Basic Principlep. 222
4.10.2 Experimental Systemp. 230
4.10.3 Testing Results and Analysisp. 230
4.11 Summaryp. 234
Referencesp. 234
5 Comprehensive Countermeasures for Improving the Performance of Transformer Differential Protectionp. 237
5.1 Introductionp. 237
5.2 A Method to Eliminate the Magnetizing Inrush Current of Energized Transformersp. 242
5.2.1 Principles and Modelling of the Inrush Suppressor and Parameter Designp. 242
5.2.2 Simulation Validation and Results Analysisp. 249
5.3 Identification of the Cross-Country Fault of a Power Transformer for Fast Unblocking of Differential Protectionp. 255
5.3.1 Criterion for Identifying Cross-Country Faults Using the Variation of the saturated Secondary Current with Respect to the Differential Currentp. 255
5.3.2 Simulation Analyses and Test Verificationp. 257
5.4 Adaptive Scheme in the Transformer Main Protectionp. 268
5.4.1 The Fundamental of the Time Difference Based Method to Discriminate between the Fault Current and the Inrush of the Transformerp. 268
5.4.2 Preset Filterp. 269
5.4.3 Comprehensive Protection Schemep. 271
5.4.4 Simulation Tests and Analysisp. 274
5.5 A Series Multiresolution Morphological Gradient Based Criterion to Identify CT Saturationp. 294
5.5.1 Time Difference Extraction Criterion Using Mathematical Morphologyp. 294
5.5.2 Simulation Study and Result Analysisp. 297
5.5.3 Performance Verification with On-site Datap. 297
5.6 A New Adaptive Method to Identify CT Saturation Using a Grille Fractalp. 304
5.6.1 Analysis of the Behaviour of CT Transient Saturationp. 304
5.6.2 The Basic Principle and Algorithm of Grille Fractalp. 308
5.6.3 Self-Adaptive Generalized Morphological Filterp. 312
5.6.4 The Design of Protection Program and the Verification of Resultsp. 313
5.7 Summaryp. 317
Referencesp. 317
Indexp. 319