Voltage Stability in Electrical Power Systems: Concepts, Assessment, and Methods for Improvement

Cover
Title Page
Copyright Page
Contents
Author Biographies
Preface
Part I Concept of Voltage Stability, Effective Factors and Devices, and Suitable System Modeling
Chapter 1 How Does Voltage Instability Occur?
1.1 Introduction
1.2 Long-Term Voltage Instability
1.2.1 A Simple System
1.2.2 Voltage Calculation
1.2.3 Illustration of Voltage Collapse
1.2.4 The Reason of Voltage Collapse Occurrence
1.2.5 The Importance of Timely Emergency Measures
1.3 Short-Term Voltage Instability
1.3.1 The Process of Induction Motors Stalling
1.3.2 Dynamic Analysis
1.3.3 Static Analysis
1.3.4 The Relationship Between Short-Term Voltage Instability and Loadability Limit
1.4 Summary
References
Chapter 2 Loads and Load Tap Changer (LTC) Transformer Modeling
2.1 Introduction
2.2 Static Load Models
2.2.1 The Constant Power Model
2.2.2 The Polynomial and Exponential Models
2.3 Dynamic Load Models
2.3.1 Exponential Recovery Model
2.3.2 Induction Motor Model
2.4 The LTC Transformers
2.4.1 The LTC Performance
2.4.2 The LTC Modeling
2.4.3 The LTC Transformer Model
2.5 Summary
References
Chapter 3 Generator Modeling
3.1 Introduction
3.2 Synchronous Generator Modeling
3.2.1 Synchronous Machine Structure
3.2.2 Dynamic Equations
3.2.3 Voltage and Current Phasors
3.2.4 Steady-State Equations
3.2.5 Simplification of Synchronous Machine Equations
3.2.6 Saturation Modeling
3.2.7 Synchronous Generator Capability Curve
3.2.8 Excitation System Modeling
3.2.9 Governor Modeling
3.2.10 Overexcitation Limiter (OXL) Modeling
3.3 Wind Power Plants
3.3.1 Fixed-Speed Induction Generator (FSIG)-based Wind Turbine
3.3.1.1 Physical Description
3.3.1.2 Induction Machine Steady-State Model
3.3.1.3 Induction Generator Dynamic Model
3.3.2 Doubly Fed Induction Generator (DFIG)-based Wind Turbine
3.3.2.1 Physical Description
3.3.2.2 DFIG Steady-State Characteristic
3.3.2.3 Optimum Wind Power Extraction
3.3.2.4 Torque Control
3.3.2.5 Voltage Control
3.4 Summary
References
Chapter 4 Impact of Distributed Generation and Transmission–Distribution Interactions on Voltage Stability
4.1 Introduction
4.2 Interactions of Transmission and Distribution Networks
4.2.1 The Studied System
4.2.2 Stable Case (Case 1)
4.2.3 Instability Due to the Inability of Transmission Transformer's LTC to Regulate Voltage (Case 2)
4.2.4 Instability Due to the Inability of Distribution Transformer's LTC to Regulate Voltage (Case 3)
4.3 Impact of Distribution Generation (DG) Units
4.3.1 Connecting DG Units to MV Distribution Networks
4.3.2 Connecting DG Units to HV Distribution Networks
4.4 Summary
References
Part II Voltage Stability Assessment Methods
Chapter 5 The Continuation Power Flow (CPF) Methods
5.1 Introduction
5.2 The CPF Elements
5.3 Predictors
5.3.1 Linear Predictors
5.3.1.1 Tangent Method
5.3.1.2 Secant Method
5.3.2 Nonlinear Predictors
5.4 Parameterization
5.4.1 Local Parameterization
5.4.2 Arclength Parameterization
5.4.3 Local Geometric Parameterization
5.4.4 Alternative Parameterization
5.5 Correctors
5.6 Determining the Prediction Step Size
5.7 Comparison of Predictors
5.8 Simulation of Local Geometric Parameterization Method
5.9 Some Real-world Applications of CPF
5.10 Summary
References
Chapter 6 PV-Curve Fitting
6.1 Introduction
6.2 Curve Fitting Using Three Power Flow Solutions
6.3 Curve Fitting Using Two Power Flow Solutions
6.4 Curve Fitting Using One Power Flow Solution
6.5 Comparison of Different PV-Curve Fitting Methods
6.6 Summary
References
Chapter 7 Measurement-Based Indices
7.1 Introduction
7.2 Thevenin Equivalent-Based Index
7.2.1 Background
7.2.2 Recursive Least Square (RLS) Algorithm
7.2.3 Calculation of XTh Assuming ETh as a Free Variable
7.2.4 Reduction of Parameter Estimation Errors
7.2.5 Simulations
7.3 Indices Based on Received Power Variations
7.4 Early Detection of Voltage Instability
7.5 Indices for Assessment Fault-Induced Delayed Voltage Recovery (FIDVR) Phenomenon
7.5.1 Concept of FIDVR
7.5.2 FIDVR Assessment Indices
7.6 Some Real-World Applications of Measurement-based Indices
7.7 Summary
References
Chapter 8 Model-Based Indices
8.1 Introduction
8.2 Jacobian Matrix-Based Indices
8.2.1 Background
8.2.2 Singularity of Jacobian Matrix at the Loadability Limit
8.2.3 Singular Values and Vectors
8.2.4 Simulation
8.2.5 Reduced Jacobian Matrix
8.2.6 Eigenvalues and Eigenvectors
8.2.7 Test Function
8.2.8 The Maximum Singular Value of the Inverse of the Jacobian Matrix
8.3 Indices Based on Admittance Matrix and Power Balance Equations
8.3.1 Line Stability Indices
8.3.1.1 Stability Index Lmn
8.3.1.2 Fast Voltage Stability Index (FVSI)
8.3.1.3 Stability Index LQP
8.3.1.4 Line Collapse Proximity Index (LCPI)
8.3.1.5 Integral Transmission Line Transfer Index (ITLTI)
8.3.2 Bus Indices
8.3.2.1 Stability Index L
8.3.2.2 Improved Voltage Stability Index (IVSI)
8.4 Indices Based on Load Buses Voltage and Generators Reactive Power
8.4.1 Reactive Power Performance Index (PIV)
8.4.2 Reactive Power Loss Index (RPLI)
8.5 Indices Defined in the Distribution System
8.5.1 Distribution System Equivalent
8.5.2 Indices
8.5.3 Simulations
8.6 Summary
References
Chapter 9 Machine Learning-Based Assessment Methods
9.1 Introduction
9.2 Voltage Stability Detection Based on Pattern Recognition Methods and Intelligent Systems
9.2.1 The Intelligent Systems Training Approaches
9.2.2 The Intelligent Systems Types
9.2.2.1 Artificial Neural Networks (ANNs)
9.2.2.2 Decision Trees (DTs)
9.2.2.3 Support-Vector Machines (SVMs)
9.3 Summary
References
Part III Methods of Preventing Voltage Instability
Chapter 10 Preventive Control of Voltage Instability
10.1 Introduction
10.2 Determination of LM
10.2.1 Static Analysis
10.2.2 Dynamic Analysis
10.3 Determination of the Optimal Value of Control Actions
10.4 Computation of Sensitivities
10.4.1 Computation of Sensitivities Based on the Computation of MLP
10.4.2 Computation of Sensitivities Without the Computation of MLP
10.5 Determination of the Most Effective Actions
10.6 Summary
References
Chapter 11 Emergency Control of Voltage Instability
11.1 Introduction
11.2 Load Shedding
11.2.1 UVLS against Long-term Voltage Instability
11.2.1.1 Centralized Rule-based Controller
11.2.1.2 Distributed Rule-based Controller
11.2.1.3 Two-level Rule-based Controller
11.2.2 UVLS Against Both Short- and Long-term Voltage Instability
11.2.3 Load Shedding Based on Incremental Value of Generator Reactive Power
11.2.4 Adaptive Load Shedding Based on Early Detection of Voltage Instability
11.3 Decentralized Voltage Control
11.4 The use of Active Distribution Networks in Emergency Voltage Control
11.5 Coordinated Voltage Control
11.5.1 Model Predictive Control
11.5.2 Prediction of Trajectory of Variables
11.5.2.1 Simplifications Required for Emergency Voltage Control in the Transmission Network
11.5.2.2 Euler State Prediction (ESP)
11.5.2.3 Two-Point Prediction Method
11.5.2.4 Prediction Using Trajectory Sensitivity
11.5.3 Cost Function
11.6 Summary
References
Index
EULA