Book excerpt: The book presents basic theories of transformer operation, design principles and methods used in power transformer designing work, and includes limitation criteria, effective utilization of material, and calculation examples to enhance readers’ techniques of transformer design and testing. It includes: Core and winding commonly used, and their performances Insulation structures and materials, methods for improvements on dielectric strengths on partial discharge, breakdown and electrical creepage Losses and impedance calculations, major influential factors, and methods to minimize load loss Cooling design and the method to obtain effective cooling Short-circuit forces calculations, the ways to reduce the short-circuit forces, and measures to raise withstand abilities No-load and load-sound levels, the influential factors and trends, and abatement techniques In-depth discussion of an autotransformer’s special features, its stabilizing winding function, and its adequate size Tests and diagnostics The ways to optimize design are also discussed throughout the book as a goal to achieve best performances on economic design. The book contains great reference material for engineers, students, teachers, researchers and anyone in the field associated with power transformer design, manufacture, testing, application and service maintenance. It also provides a high level of detail to help future research and development maintain electrical power as a reliable and economical energy resource.