High-Voltage Power-Transformer Design

A core-type power-transformer design with shielded high-voltage winding and graded insulation has been developed for application in the higher-voltage classifications, and up to the present time more than one-quarter million kilovolt-ampere capacity of this kind of transformer has been manufactured and placed in service. The design employs a new form of construction for high-voltage power transformers which has been called ``distributed concentric´´ construction. Outstanding characteristics of the distributed-concentric-type transformer include: 1. Reduced inherent reactance resulting in a reduction of critical materials for a given specification. 2. Ready adaptability to forced oil flow directed through the winding ducts resulting in a reduction of critical materials for a given thermal capacity. 3. Strategic distribution of voltage stress throughout the dielectric structure. 4. Simple and stable mechanical construction of windings, insulation, and shield.