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About this book

This book presents the state-of-the-art approach for transmission line protection schemes for smart power grid. It provides a comprehensive solution for real-time development of numerical relaying schemes for future power grids which can minimize cascade tripping and widespread blackout problems prevailing all around the world. The book also includes the traditional approach for transmission line protection along with issues and challenges in protection philosophy. It highlights the issues for sheltering power grid from unwanted hazards with very fundamental approach. The book follows a step-by-step approach for resolving critical issues like high impedance faults, power swing detection and auto-reclosing schemes with adaptive protection process. The book also covers the topic of hardware solution for real-time implementation of auto-reclosing scheme for transmission line protection schemes along with comparative analysis with the recently developed analytical approach such as Artificial Neural Network (ANN), Support Vector Machine (SVM) and other machine learning algorithms. It will be useful to researchers and industry professionals and students in the fields of power system protection.

Table of Contents

Frontmatter

Chapter 1. Transmission Line Protection Philosophy

Without Abstract
Ujjaval Patel, Praghnesh Bhatt, Nilesh Chothani

Chapter 2. Transmission Line Protection: Issues and Research Needs

Abstract
There are various factors associated with implementation and operation of distance protection schemes. Out of the many issues, the potential issues are presented in this chapter along with the main objectives and plan of research work carried out for transmission line protection.
Ujjaval Patel, Praghnesh Bhatt, Nilesh Chothani

Chapter 3. Adaptive Numerical Distance Relaying Scheme

Abstract
Impedance reach of numerical distance relay is severely affected by fault resistance (RF), fault inception angle (FIA), fault type (FT), fault location (FL), power flow angle (PFA), series compensation in transmission and load encroachment. This chapter presents a novel standalone adaptive distance protection algorithm for detection, classification, and location of faults in the presence of variable fault resistance under the influence of outlined parameters. It is based on adaptive slope tracking method to detect and classify the fault in conjunction with modified Fourier transform algorithm for estimation of fault location. Due to the adaptive setting of quadrilateral characteristics in accordance with variation in fault impedance, the proposed technique is highly accurate for detection and classification of faults with error in fault location estimation to be within 1%. Moreover, the proposed technique provides a significant improvement in operating time and estimation of fault location as compared to existing distance relaying algorithms which are the key attributes of multi-functional numerical relay for real-time implementations.
Ujjaval Patel, Praghnesh Bhatt, Nilesh Chothani

Chapter 4. Discrimination Between Power Swing and Line Fault Based on Voltage and Reactive Power Sensitivity

Abstract
One of the major concerns responsible for widespread blackout is power swing which occurs due to rapid swift in system configuration or load patterns in transmission network. It may aggravate undesirable tripping of protective elements. Proper discrimination between power swing and fault is the complicated task for protection engineers. This chapter projects an innovative discrimination method based on voltage and reactive power sensitivity at relay location. Power swing condition is analyzed by series of disturbances such as variation in mechanical power input to synchronous generator, outage of parallel line due to fault and sudden appliance / removal of heavy load. It is publicized that the proposed scheme responds successfully and issues trip signal during fault and leftovers out of action during power swing condition. The developed scheme has been also validated for symmetrical fault incepted during power swing, and it outperforms with promising accuracy.
Ujjaval Patel, Praghnesh Bhatt, Nilesh Chothani

Chapter 5. Sequence-Space-Aided Disturbance Classifier Scheme Based on Support Vector Machine

Abstract
Smart power grids are equipped with series compensation in order to improve the power transfer capability. Sudden changes in loading or weak constitution of series compensated transmission line network cause power swing which may aggravate miss-operation of protective elements. Consequently, it becomes utmost essential to rapidly and accurately distinguish between fault and power swing conditions to prevent instability in smart power grid equipped with compensation. This research demonstrates an effective disturbance classifier scheme for series compensated transmission line for discrimination during disparity in power grid contexts using sequence-space-based support vector machine (SVM) classifier. The test data sets are generated by performing extensive simulations in PSCAD software by varying system and fault context. The developed scheme is also evaluated for symmetrical fault detection during power swing and shows remarkable improvement in accuracy and speed for protection of series compensated transmission line in comparison to existing schemes.
Ujjaval Patel, Praghnesh Bhatt, Nilesh Chothani

Chapter 6. Auto-Reclosing Scheme with Adaptive Dead Time Control Based on Synchro-Check Principle

Abstract
Series compensation plays important role in smart power grid to improve power transfer capacity and voltage profiles. Majority of faults occurring in the grid are transient in nature. However, the discrimination between transient fault and permanent fault are contemporary problems in the field of distance protection of transmission line. Advanced numerical relays implement auto-reclosing feature to detect the transient fault and regain the service continuity automatically when the transient fault is cleared. The research work outlined in this chapter presents an auto-reclosure scheme using synchronized voltage phasors across the breaker pole along with adaptive dead time control to enhance system stability. The developed auto-reclosing scheme provides adaptive dead time control for both uncompensated and series compensated transmission lines as compared to conventional schemes which normally respond with fix dead time control.
Ujjaval Patel, Praghnesh Bhatt, Nilesh Chothani

Chapter 7. Summary of Proposed Work

Abstract
It can be narrated that the proposed advanced numerical schemes effectively protects the transmission line in comparison with existing schemes. It assists protection engineers for execution for many complications during system failures. The proposed schemes not only generate the trip signal at the time of fault but it also recognizes fault instance, fault type, and fault location. At the same time, the proposed scheme also blocks the unwanted tripping of circuit breaker during power swing and load encroachment. Moreover, the developed auto-reclosing scheme with adaptive dead time control effectively improves the stability of the power system under consideration. This chapter demonstrates summary of promising outcomes of developed schemes along with comparative improvements over existing numerical relaying for future developments. It also explores the scope for future research to shelter smart power grid for delivering continuous reliable power supply.
Ujjaval Patel, Praghnesh Bhatt, Nilesh Chothani

Backmatter

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