In July 2012 there was blackout in India. As the result of this disturbance there were two blackouts. In first blackout only the Northern Grid was affected but in the second blackout Northern, Eastern and North-Eastern grid collapsed. A committee formed by the government analyzed the events that resulted in the collapse of system and pointed out no of factors that lead to disturbance.
Whole grid collapsed under load encroachment condition. In this thesis different factors have been analyzed using PSCAD simulation and solutions have been proposed.
Approximate model of Indian power system has been developed in PSCAD using approximate parameters given in Grid Failure Report issued by the Indian government. Increase in installed capacity of power system and its impact on system frequency and rotor angle has been studied.
A new algorithm has been proposed for distance relay operation in Zone 3 to avoid power system blackout using Indian grid model. One of the main factors that lead to the collapse of whole system was the operation of zone 3 distance relay on 400kV Bina-Gwalior Line. This scheme will improve system stability under heavy load conditions. A simplified model in PSCAD was established in order to study the zone 3 protection of distance relay.
Table of Contents
CHAPTER. 1 INTRODUCTION OF INDIAN POWER SYSTEM BLACKOUT
1.1 Research background and significance
1.2 Approximate Model of Indian Grid
1.3 Power Flow during Grid Disturbance
1.4 Analysis of the Grid Disturbance and Blackout
1.4.1 Depletion of Power Transmission Network
1.4.2 Frequency Control of System
1.4.3 Load Management on Gwalior-Bina Line
1.4.4 Flaws in Protection Schemes specifically zone 3
1.5 Main Work of This Paper
CHAPTER. 2 STUDY OF SYSTEM UNDER DIFFERENT CASES AND SOLUTIONS
2.1 Introduction
2.2 General Situation of Indian Power System
2.3 Improvement in System Frequency and Rotor Angle Change because of Thermal Generation in Northern Grid
2.3.1 Improvement in System Frequency
2.3.2 Change in Rotor Angle
2.4 Improvement in system frequency and Rotor Angle Change because of Wind Generation in Western Grid
2.4.1 Improvement in System Frequency
2.4.2 Change in Rotor Angle
2.5 Tripping of Gwalior-Bina Line and System Blackout
2.6 Conclusion
CHAPTER. 3 ZONE THREE PROTECTION
3.1 Introduction
3.2 Distance Relay Settings of Northern Region and Western Region Line
3.3 Power Swing Detection Algorithm
3.3.1 System Operation under Normal Conditions
3.3.2 System Operation under Power Swing
3.3.3 Simulation Results
3.4 Synchronous Fault Detection Algorithm
3.4.1 System Operation under Synchronous Fault Conditions
3.4.2 Simulation Results
3.5 Asynchronous Fault Detection Algorithm
3.5.1 System Operation under Asynchronous Fault Conditions
3.5.2 Simulation Results
3.6 Conclusion
CHAPTER. 4 ADVANCE SCHEME TO AVOID BLACKOUT
4.1 Introduction
4.2 Power Swing Detection Algorithm
4.2.1 Principle of Algorithm
4.2.2 Simulation Results
4.2.3 Phase Voltage at the Beginning of Line
4.3 Three Phase Fault Detection Algorithm
4.3.1 Principle of Algorithm
4.3.2 Simulation Results
4.4 Unbalanced Fault Detection Algorithm
4.4.1 Principle of Algorithm
4.4.2 Simulation Results
4.5 Conclusion
CHAPTER. 5 SUMMARY AND PROSPECT
5.1 Summary
5.2 Prospect
Objectives & Core Themes
The primary objective of this dissertation is to analyze the factors contributing to the July 2012 power grid failure in India and to propose a new, robust algorithm for distance relay operation in Zone 3. The study aims to enhance system stability by accurately distinguishing between actual faults and load encroachment under heavy load or power swing conditions, thereby preventing unnecessary line tripping and subsequent cascading blackouts.
- Analysis of Indian power grid failure mechanisms (load encroachment and frequency instability).
- Development of an improved protection scheme for Zone 3 distance relays.
- Simulation and validation of power system behavior using PSCAD under various stress scenarios.
- Proposing advanced detection algorithms for power swings, three-phase faults, and unbalanced faults.
Excerpt from the book
1.4.4 Flaws in Protection Schemes specifically zone 3
Distance relay settings have also played an important role in making the situation complex. Distance relay in zone 3 tripped while the Gwalior-Bina line was not thermally overloaded loaded. In other words current ratings of the conductor were not exceeded. Relay settings could not distinguish between fault and load encroachment.
The first tripping occurred on 400kv Gwalior-Bina line. This tripping occurred on zone 3. The system was not thermally loaded and it was expected to survive but it collapsed in zone 3. Zone 3 distance relay perceived load encroachment as fault. It is noted that on both days, the grid disturbance was initiated by tripping of 400 kV Bina-Gwalior line on zone-3 of Main-II protection, though there were several other concurrent conditions, which ultimately led to collapse of grid. There is no doubt that this tripping is attributable to load encroachment i.e. the current and voltage conditions were such that the protection system perceived it as fault (during fault, current becomes very high and voltage goes down to very low levels). Thereafter, there were several tripping on load encroachment and power swing. It is also noted that on both days, only Main-II protections operated and Main-I protection did not pick up.
Distances relay settings for zone 3 needs to carefully set. It should be able to distinguish load encroachment and fault. a new protection scheme for improving the performance of the distance protective relays in transmission systems. The determination of fault zone by the proposed scheme is based on data sheared locally with other distance relays at the same station, in addition to a command from the distance relay on the other end of the protected line. In some cases the impedance measured by a distance relay at one end of the line may reduce to a point where it is less than the tripping condition for that relay for back-up
Summary of Chapters
CHAPTER. 1 INTRODUCTION OF INDIAN POWER SYSTEM BLACKOUT: Discusses the background of India's power infrastructure and the causal factors of the 2012 blackouts, emphasizing the unintended tripping of Zone 3 distance relays.
CHAPTER. 2 STUDY OF SYSTEM UNDER DIFFERENT CASES AND SOLUTIONS: Analyzes the Indian power system's response to thermal and wind generation variations and evaluates frequency stability under different load conditions.
CHAPTER. 3 ZONE THREE PROTECTION: Introduces algorithms for detecting power swings and faults to ensure that distance relays only operate during genuine fault conditions.
CHAPTER. 4 ADVANCE SCHEME TO AVOID BLACKOUT: Proposes refined algorithms for detecting power swings and three-phase or unbalanced faults to significantly improve system reliability.
CHAPTER. 5 SUMMARY AND PROSPECT: Summarizes the key findings regarding the proposed protection schemes and offers future directions for improving power system stability globally.
Keywords
Distance Relay, Zone 3, Power System, Blackout, Power Swing, Load Encroachment, System Frequency, Rotor Angle, PSCAD, Thermal Generation, Wind Generation, Transmission Network, Fault Detection, Grid Stability, Relay Settings
Frequently Asked Questions
What is the fundamental purpose of this research?
The study focuses on identifying why Indian power grids experienced massive blackouts due to improper relay operations and proposes a new algorithmic scheme to prevent such occurrences.
Which key thematic areas are covered?
Key areas include Indian grid infrastructure analysis, the physics of load encroachment, protection scheme limitations, and the simulation of power system stability during disturbances.
What is the primary research goal?
The goal is to develop and validate an algorithm that allows distance relays to distinguish between load encroachment and actual faults, preventing unnecessary, cascading grid trips.
What scientific methods are utilized?
The author employs system modeling and simulation using the PSCAD software to analyze generator parameters, frequency fluctuations, and rotor angle behavior.
What topics are discussed in the main chapters?
The chapters cover the root causes of the 2012 blackout, thermal/wind generation effects on system stability, Zone 3 protection logic, and advanced detection schemes for various fault types.
Which keywords characterize this work?
Key terms include Distance Relay, Zone 3, Power Swing, Load Encroachment, PSCAD, and Grid Stability.
Why did the Zone 3 distance relay cause a grid collapse?
The relay incorrectly identified high load conditions (load encroachment) as a fault, leading to a premature trip that cascaded into a system-wide blackout.
How does the proposed "Advance Scheme" improve reliability?
It adds specific logical parameters to the relay settings that block tripping during non-fault conditions, such as during normal power swings, ensuring the grid remains connected when stable.
- Quote paper
- Muhammah Adnan (Author), 2016, Implementation of New Scheme on Indian Power System for Distance Relay Operation in Zone 3 to Avoid Power System Blackout, Munich, GRIN Verlag, https://www.grin.com/document/339081
