Fault Analysis and Protection System Design for DC Grids (Power Systems)

✍ Scribed by Abhisek Ukil, Yew Ming Yeap, Kuntal Satpathi

• Publisher: Springer
• Year: 2020
• Tongue: English
• Leaves: 402
• Category: Library

✦ Synopsis

This book offers a comprehensive reference guide to the important topics of fault analysis and protection system design for DC grids, at various voltage levels and for a range of applications. It bridges a much-needed research gap to enable wide-scale implementation of energy-efficient DC grids. Following an introduction, DC grid architecture is presented, covering the devices, operation and control methods. In turn, analytical methods for DC fault analysis are presented for different types of faults, followed by separate chapters on various DC fault identification methods, using time, frequency and time-frequency domain analyses of the DC current and voltage signals. The unit and non-unit protection strategies are discussed in detail, while a dedicated chapter addresses DC fault isolation devices. Step-by-step guidelines are provided for building hardware-based experimental test setups, as well as methods for validating the various algorithms. The book also features several application-driven case studies.

✦ Table of Contents

Preface
Contents
1 Introduction to DC Grid
1.1 Introduction
1.2 DC Grid Applications
1.2.1 Transmission Systems
1.2.2 Utilities and Microgrid
1.2.3 Datacenters
1.2.4 Transportation Systems
1.3 Relevant Standards and Voltage Levels
1.3.1 Standards
1.3.2 Voltage Levels
1.4 Power Quality Issues
1.5 Challenges in DC Grids: Design of Protection System
1.5.1 Repercussions of Faults in Existing Power Systems
1.5.2 Challenges with Fault Detection in DC Grids
1.5.3 Challenges with Fault Isolation in Grids
1.5.4 Some Practical Challenges
References
2 Components and Architectures of DC Grid for Various Applications
2.1 Introduction
2.2 Components in DC Grids
2.2.1 Diode Bridge Converters
2.2.2 Thyristor Based Current Source Converters
2.2.3 IGBT Based Voltage Source Converters
2.2.4 Emerging Converter Topologies
2.2.5 DC/DC Converters
2.2.6 Energy Storage Technologies
2.3 DC Grid Architectures and Applications
2.3.1 Transmission Applications: HVDC Systems
2.3.2 Utilities Applications: Microgrids
2.3.3 Datacenter Applications
2.3.4 Transportation Applications
References
3 Modeling and Control of Generation System for DC Grid Applications
3.1 Introduction
3.2 Generation Systems for HVDC and Microgrid Applications
3.2.1 CSC-Based Generation System
3.2.2 VSC-Based Generation System
3.3 Generation Systems for Marine and Aerospace Applications
3.3.1 AVR Based Generation System
3.3.2 AFR Based Generation System
3.3.3 Comparison
References
4 Faults in DC Networks
4.1 Introduction
4.1.1 Types of Faults in DC Networks
4.1.2 Statistics of Faults in DC Networks
4.1.3 Effect of Topology on Faults in DC Networks
4.2 Fault Current Calculations: CSC-Based DC System
4.3 Fault Current Calculations: VSC-Based DC System
4.3.1 Pole-to-Pole Fault
4.3.2 Pole-to-Ground Fault
4.4 Fault Current Calculations: MMC-Based DC System
4.4.1 Pole-to-Pole Fault
4.4.2 Pole-to-Ground Fault
4.5 Fault Current Calculation: Travelling Wave Approach
4.6 Example
References
5 Time-Domain Based Fault Detection in DC Grids
5.1 Introduction
5.2 Overcurrent Based Protection
5.3 Rate of Change-Based Protection
5.3.1 Current
5.3.2 Voltage
5.3.3 Practical Application
5.4 Capacitive Discharge Method
5.4.1 Background
5.4.2 Principle of Operation
5.4.3 Example
5.5 Conclusion
References
6 Frequency-Domain Based Fault Detection: Application of Short-Time Fourier Transform
6.1 Introduction
6.2 Operation of STFT
6.3 Application of STFT to Constant and Step Change in DC Current
6.3.1 STFT Application on Constant DC Current
6.3.2 STFT Application on Step Change in DC Current
6.4 Fault Detection by STFT
6.4.1 Fault Detection Criteria
6.4.2 Selection of Window Length
6.4.3 Effect of Window Function
6.4.4 Determining Tripping Threshold
6.4.5 Implementing STFT Based Fault Detection
6.5 Test System to Evaluate STFT Based Fault Detection Algorithm
6.5.1 Point-to-Point DC System
6.5.2 Multi-terminal DC System
6.6 Conclusion
References
7 Time-Frequency Domain Analysis: Wavelet-Transform Based Fault Detection
7.1 Introduction
7.2 Selection of Mother Wavelet
7.3 Detection Algorithm
7.4 Example
7.4.1 Two-Terminal HVDC System
7.4.2 Multi-terminal HVDC System
7.5 Conclusion
References
8 Non-unit Protection Strategies for DC Power Systems
8.1 Introduction
8.2 Non-unit Protection Strategies in AC System and Implementation Challenges in DC System
8.3 Fault Current Computation: Current Derivatives and Associated Parameters
8.3.1 Computing Peak Fault Current and Time to Reach Peak Fault Current
8.3.2 Computing Derivative Using Difference Equations
8.3.3 Comparison of Approximation of Derivative
8.4 System Description for Non-unit Protection Studies
8.5 Definite Time Based Protection Coordination
8.5.1 Using Current Magnitude
8.5.2 Using Current Derivatives
8.6 Definite Time Based Protection Coordination Using Estimated Inductance
8.7 Conclusion
References
9 Introduction to Directional Protection and Communication Assisted Protection Systems
9.1 Introduction
9.2 Need for Directional Protection
9.3 Analysis of Directional Fault Currents
9.3.1 System Description
9.3.2 Fault Analysis Using Superimposed Quantities
9.4 Directional Protection Design
9.4.1 Directional Element Design
9.4.2 Fault Detection
9.5 Performance Comparison of Various Directional Protection Strategies
9.6 Communication Assisted Protection Strategies
9.7 Conclusion
References
10 Fault Isolation in DC Grids
10.1 Introduction
10.2 Time Line of Fault Isolation
10.3 DC Grid Protection Devices
10.4 DC Circuit Breakers
10.4.1 Resonant Type DC Breaker
10.4.2 Non-resonant Type DC Breaker
10.5 Converter Based Isolation
10.5.1 SSCB Based on VSC with Freewheeling Diode
10.5.2 SSCB Based on H-Bridge Converter
10.6 Commercial DC Breakers
10.6.1 HVDC
10.6.2 MVDC
10.6.3 LVDC
References
11 Design of Experiment and Fault Studies
11.1 Introduction
11.2 Experimental Setup Description
11.2.1 Converter
11.2.2 DC Line
11.2.3 Measurement and Control
11.2.4 Controller Tuning
11.2.5 Fault and Protection Measure
11.3 Experimental Results
11.3.1 Steady State
11.3.2 Fault on DC Line
11.3.3 Load Change
11.4 Validation of Fault Detection Methods on Real Fault Signal
11.4.1 Wavelet Transform
11.4.2 Capacitive Discharge
11.4.3 Short-Time Fourier Transform
11.4.4 Comparison
11.5 Conclusion
References
12 Case Studies
12.1 Introduction
12.2 Protection System Design for Long-Distance HVDC Systems
12.2.1 Fault Clearance and Recovery Strategy
12.2.2 Fault Clearance Method
12.2.3 Recovery Strategy
12.2.4 Results and Discussion
12.3 Protection System Design for Compact DC Distribution Systems
12.3.1 Transient Analysis and Protection Requirements
12.3.2 Fault Detection and Selectivity Methods
12.3.3 Protection Design
12.4 Conclusion
References
Appendix Index
Index