电力变压器差动保护中涌流的辨识
发布时间：2024-10-04 16:49
在电力变压器差动保护中,主要关注的是如何成功地识别励磁涌流。本文提出了一种基于离散小波变换的内部故障与涌流的判别方法。应用小波变换将差动电流分解为多阶频带的细节系数;通过对不同的涌流和内部故障情况的研究分析,发现在细节系数变化显著的情况下,故障条件是最有可能的。这一事实被用来建立一个判断标准,将相对小波能量定义为特征量以提取不同不同时刻的特征。另外,以能量变化量为基础,在两个连续的时间间隔内对相对小波能量的值进行了比较监测,在这一差异不是很显著量的情况下则认为是励磁涌流。在MATLAB仿真平台上进行了该算法的性能评估,并对不同的瞬态情况进行了仿真实验。
【文章页数】：67 页
【学位级别】：硕士
【文章目录】：
摘要
ABSTRACT
CHAPTER 1 INTRODUCTION
1.1 Background
1.2 Research Status and Problem Statement
1.2.1 Harmonic Restraint
1.2.2 Flux, Voltage Restraints and Transformer Inductance Scheme
1.2.3 Wave Shape Recognition Methods
1.2.4 Pattern Recognition Methods
1.2.4.1 Artificial Neural Network
1.2.4.2 Fuzzy System
1.3 Research Significance and Objective
1.4 Thesis layout
CHAPTER 2 DIFFERENTIAL PROTECTION AND INRUSH CURRENT
2.1 Introduction
2.2 Differential Protection
2.2.1 The Principle of Differential Protection
2.2.2 CTs and CTs Connections
2.2.3 Differential Protection Considerations
2.3 The Percentage Differential Protection
2.3.1 Implementation of Percentage Differential Protection
2.3.2 Percentage Differential Protection Challenges
2.4 Transformer Inrush Current
2.4.1 The Nature of the Inrush Current
2.4.2 The Inrush Current Characteristics
2.4.3 Analysis of the Inrush Current
CHAPTER 3 THE APPROACH OF INRUSH CURRENT IDENTIFICATION
3.1 Introduction
3.2 Wavelet Transform
3.2.1 Introduction
3.2.2 Discrete Wavelet Transform DWT
3.2.3 DWT and Filters Bank
3.3 Power System Configuration
3.3.1 Power Transformer Model
3.3.2 Proposed Electric Power System
3.4 Proposed Approach
3.4.1 Relative Wavelet Energy
3.4.2 Discrimination Criterion
CHAPTER 4 EVALUATION THE PERFORMANCE OF THE APPROACH
4.1 Introduction
4.2 Results and Discussion
4.2.1 The Case of Energizing the Power Transformer (Inrush Current)
4.2.2 The Case of Internal faults at the Power Transformer Terminals subsequent to its Energization
4.2.3 The Case of Internal faults at the Power Transformer Terminals during Normal Operation
CHAPTER 5 CONCLUSION AND FUTURE WORK
5.1 Conclusion
5.2 Future Work
REFERENCES
ACKNOWLEDGEMENT
本文编号：4006923
【文章页数】：67 页
【学位级别】：硕士
【文章目录】：
摘要
ABSTRACT
CHAPTER 1 INTRODUCTION
1.1 Background
1.2 Research Status and Problem Statement
1.2.1 Harmonic Restraint
1.2.2 Flux, Voltage Restraints and Transformer Inductance Scheme
1.2.3 Wave Shape Recognition Methods
1.2.4 Pattern Recognition Methods
1.2.4.1 Artificial Neural Network
1.2.4.2 Fuzzy System
1.3 Research Significance and Objective
1.4 Thesis layout
CHAPTER 2 DIFFERENTIAL PROTECTION AND INRUSH CURRENT
2.1 Introduction
2.2 Differential Protection
2.2.1 The Principle of Differential Protection
2.2.2 CTs and CTs Connections
2.2.3 Differential Protection Considerations
2.3 The Percentage Differential Protection
2.3.1 Implementation of Percentage Differential Protection
2.3.2 Percentage Differential Protection Challenges
2.4 Transformer Inrush Current
2.4.1 The Nature of the Inrush Current
2.4.2 The Inrush Current Characteristics
2.4.3 Analysis of the Inrush Current
CHAPTER 3 THE APPROACH OF INRUSH CURRENT IDENTIFICATION
3.1 Introduction
3.2 Wavelet Transform
3.2.1 Introduction
3.2.2 Discrete Wavelet Transform DWT
3.2.3 DWT and Filters Bank
3.3 Power System Configuration
3.3.1 Power Transformer Model
3.3.2 Proposed Electric Power System
3.4 Proposed Approach
3.4.1 Relative Wavelet Energy
3.4.2 Discrimination Criterion
CHAPTER 4 EVALUATION THE PERFORMANCE OF THE APPROACH
4.1 Introduction
4.2 Results and Discussion
4.2.1 The Case of Energizing the Power Transformer (Inrush Current)
4.2.2 The Case of Internal faults at the Power Transformer Terminals subsequent to its Energization
4.2.3 The Case of Internal faults at the Power Transformer Terminals during Normal Operation
CHAPTER 5 CONCLUSION AND FUTURE WORK
5.1 Conclusion
5.2 Future Work
REFERENCES
ACKNOWLEDGEMENT
本文编号：4006923
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