Updating and reorganizing the valuable information in the first edition to enhance logical development, Transformer Design Principles: With Applications to Core-Form Power Transformers, Second Edition remains focused on the basic physical concepts behind transformer design and operation. Starting with first principles, this book develops the reader’s understanding of the rationale behind design practices by illustrating how basic formulae and modeling procedures are derived and used. Simplifies presentation and emphasizes fundamentals, making it easy to apply presented results to your own designs The models, formulae, and methods illustrated in this book cover the crucial electrical, mechanical, and thermal aspects that must be satisfied in transformer design. The text also provides detailed mathematical techniques that enable users to implement these models on a computer. The authors take advantage of the increased availability of electromagnetic 2D and 3D finite element programs, using them to make calculations, especially in conjunction with the impedance boundary method for dealing with eddy current losses in high-permeability materials such as tank walls. Includes new or updated material on: Multi terminal transformers Phasors and three-phase connections Impulse generators and air core reactors Methodology for voltage breakdown in oil Zig-zag transformers Winding capacitances Impulse voltage distributions Temperature distributions in the windings and oil Fault type and fault current analyses Although the book’s focus is on power transformers, the transformer circuit models presented can be used in electrical circuits, including large power grids. In addition to the standard transformer types, the book explores multi-terminal transformer models, which allow complicated winding interconnections and are often used in phase shifting and rectifying applications. With its versatile coverage of transformers, this book can be used by practicing design and utility engineers, students, and anyone else who requires knowledge of design and operational characteristics.

Table of Contents:
Introduction Historical Background Uses in Power Systems Core-Form and Shell-Form Transformers Stacked and Wound Core Construction Transformer Cooling Winding Types Insulation Structures Structural Elements Modern Trends Magnetism and Related Core Issues Basic Magnetism Hysteresis Magnetic Circuits Inrush Current Distinguishing Inrush from Fault Current Optimal Core Stacking Circuit Model of a Two-Winding Transformer with Core Circuit Model of the Core Two-Winding Transformer Circuit Model with Core Approximate Two-Winding Transformer Circuit Model without Core Vector Diagram of a Loaded Transformer with Core Per-Unit System Voltage Regulation Reactance and Leakage Reactance Calculations General Method for Determining Inductances and Mutual Inductances Two-Winding Leakage Reactance Formula Ideal Two-, Three-, and Multiwinding Transformers Leakage Reactance for Two-Winding Transformers Based on Circuit Parameters Leakage Reactances for Three-Winding Transformers Phasors, Three-Phase Connections, and Symmetrical Components Phasors Wye and Delta Three-Phase Connections Zig-Zag Connection Scott Connection Symmetrical Components Fault Current Analysis Fault Current Analysis on Three-Phase Systems Fault Currents for Transformers with Two Terminals per Phase Fault Currents for Transformers with Three Terminals per Phase Asymmetry Factor Phase-Shifting and Zig-Zag Transformers Basic Principles Squashed Delta Phase-Shifting Transformer Standard Delta Phase-Shifting Transformer Two-Core Phase-Shifting Transformer Regulation Effects Fault Current Analysis Zig-Zag Transformer Multi-terminal Three-Phase Transformer Model Theory Transformers with Winding Connections within a Phase Multiphase Transformers Generalizing the Model Regulation and Terminal Impedances Multiterminal Transformer Model for Balanced and Unbalanced Load Conditions Rabins’ Method for Calculating Leakage Fields, Leakage Inductances, and Forces in Transformers Theory Rabins’ Formula for Leakage Reactance Application of Rabins’ Method to Calculate the Self-Inductance of and Mutual Inductance between Coil Sections Determining the B-Field Determination of Winding Forces Numerical Considerations Mechanical Design Force Calculations Stress Analysis Radial Buckling Strength Stress Distribution in a Composite Wire-Paper Winding Section Additional Mechanical Considerations Electric Field Calculations Simple Geometries Electric Field Calculations Using Conformal Mapping Finite Element Electric Field Calculations Capacitance Calculations Distributive Capacitance along a Winding or Disk Stein’s Disk Capacitance Formula General Disk Capacitance Formula Coil Grounded at One End with Grounded Cylinders on Either Side Static Ring on One Side of Disk Terminal Disk without a Static Ring Capacitance Matrix Two Static Rings Static Ring Between the First Two Disks Winding Disk Capacitances with Wound-in Shields Multistart Winding Capacitance Voltage Breakdown and High-Voltage Design Principles of Voltage Breakdown Geometric Dependence of Transformer-Oil Breakdown Insulation Coordination Continuum Model of Winding Used to Obtain the Impulse-Voltage Distribution Lumped-Parameter Model for Transient Voltage Distribution Losses No-Load or Core Losses Load Losses Tank and Shield Losses Due to Nearby Busbars Tank Losses Associated with the Bushings Thermal Design Thermal Model of a Disk Coil with Directed Oil Flow Thermal Model for Coils without Directed Oil Flow Radiator Thermal Model Tank Cooling Oil Mixing in the Tank Time Dependence Pumped Flow Comparison with Test Results Determining m and n Exponents Loss of Life Calculation Cable and Lead Temperature Calculation Tank Wall Temperature Calculation Tieplate Temperature Core Steel Temperature Calculation Load Tap Changers General Description of Load Tap Changer Types of Regulation Principles of Operation Connection Schemes General Maintenance Miscellaneous Topics Setting the Impulse Test Generator to Achieve Close to Ideal Waveshapes Impulse or Lightning Strike on a Transformer through a Length of Cable Air Core Inductance Electrical Contacts References Index