Modeling Techniques in Power Systems
1 Introduction
General Background
The New Computer Environment
Transmission System Developments
Theoretical Models and Computer Programs
2 Transmission Systems
Introduction
Linear Transformation Techniques
Basic Single-phase Modeling
Transmission lines
Transformer on nominal ratio
Off-nominal transformer tap representation
Phase-shifting representation
Three-phase System Analysis
Discussion of the frame of reference
The use of compound admittances
Rules for forming the admittance matrix of simple networks
Network subdivision
Three-phase Models of Transmission Lines
Series impedance
Shunt admittance
Equivalent 7r model
Mutually coupled three-phase lines
Consideration of terminal connections
Shunt elements
Series elements
Line sectionalization
Evaluation of Overhead Line Parameters
Earth impedance matrix
Geometrical impedance matrix and admittance matrix
Conductor impedance matrix
Series impedance approximation for electromagnetic
transients
Underground and Submarine Cables
Three-phase Models of Transformers
Primitive admittance model of three-phase transformers
Models for common transformer connections
Three-phase transformer models with independent phase tap
control
Sequence components modeling of three-phase transformers
Formation of the System Admittance Matrix
3 FACTS and HVDC Transmission
Introduction
Flexible a.c. Transmission Systems
Thyristor controlled series compensator (TCSC)
Static on-load tap changing
Static phase shifter
Static VAR compensator
The static compensator (STATCOM)
Unified power flow controller (UPFC)
High Voltage Direct Current Transmission
The a.c.-d.c. converter
Commutation reactance
d.c. link control
Three-phase model
Load Flow
Introduction
Basic Nodal Method
Conditioning of Y Matrix
The Case Where One Voltage is Known
Analytical Definition of the Problem
Newton-Raphson Method of Solving Load Flows
Equations relating to power system load flow
Techniques Which Make the Newton-Raphson Method
Competitive in Load Flow
Sparsity programming
Triangular factorization
Optimal ordering
Aids to convergence Characteristics
Newton-Raphson Load Flow
Decoupled Newton Load Flow
Fast Decoupled Load Flow
Convergence Criteria and Tests
Numerical Example
Load Flow for Stability Assessment
Post-disturbance power flows
Modeling techniques
Sensitivity analysis
Three-phase Load Flow
Notation
Synchronous machine modeling
Specified variables
Derivation of equations
Decoupled three-phase algorithm
Structure of the computer program
5 Load Flow under Power Electronic Control
Introduction
Incorporation of FACTS Devices
Static tap changing
Phase-shifting (PS)
Thyristor controlled series capacitance (TCSC)
Unified power flow controller (UPFC)
Incorporation of HVDC Transmission
Converter model
Solution techniques
Control of converter a.c. terminal voltage
Extension to multiple and/or multiterminal d.c. systems
d.c. convergence tolerance
Test system and Numerical example
6 Electromagnetic Transients
Introduction
Background and Definitions
Numerical Integrator Substitution
Resistance
Inductance
Capacitance
Transmission Lines and Cables
Bergeron line model
Multi-conductor transmission lines
Frequency-dependent model
Formulation and Solution of the System Nodal
Equations
Modification for switching and varying parameters
Non-linear or time varying parameters
Use of Subsystems
Switching Discontinuities
Voltage and current chatter due to discontinuities
Root-matching Technique
Exponential form of difference equation
Root-matching implementation
Numerical illustration
a.c./d.c. Converters
Synchronous Machine Model
Transformer Model
The PSCAD/EMTDC Program
Structure of the program
PSCADIEMTDC
PSCADIEMTDC test cases
Real Time Digital Simulation
State Variable Analysis
State variable formulation
Solution procedure
Choice of state variables
7 System Stability
Introduction
The form of the equations
Frames of reference
Synchronous Machines-Basic Models
Mechanical equations
Electrical equations
Synchronous Machine Automatic Controllers
Automatic voltage regulators
Speed governors
Hydro and thermal turbines
Modeling lead-lag circuits
Loads
Low-voltage problems
The Transmission Network
Overall System Representation
Mesh matrix method
Nodal matrix method
Synchronous machine representation in the network
Load representation in the network
System faults and switching
Integration
Problems with the trapezoidal method
Programming the trapezoidal method
Application of the trapezoidal method
Structure of a Transient Stability Program
Overall structure
Structure of machine and network iterative solution
Advanced Component Models
Synchronous machine saturation
Detailed turbine model
Induction machines
Relays
Unbalanced faults
8 System Stability under Power Electronic
Control
Introduction
Description of the Algorithm
Data flow
Modifications required to the component programs
Equivalent circuit components
Interface variables derivation
Quasi Steady-state Converter Simulation
Rectifier loads
d.c. link
Representation of converters in the network
Inclusion of converters in the transient stability program
Static VAR Compensation Systems
Representation of SVS in the overall system
9 Fault Level Derivation
Short Circuit Analysis
System equations
Fault calculations
10 Numerical Integration Methods
Introduction
Properties of the Integration Methods
Accuracy
Stability
Stiffness
Predictor-Corrector Methods
Runge- Kutta Methods
11 Test Systems used in the various topics