IEEE Guide for Transformers Directly Connected to Generators

The selection, application, and specification considerations for the unit transformer and unit auxiliaries transformers are described, taking into account their connections, voltage and kilovoltampere ratings, and excitation and through-fault capabilities during possible operating conditions, both normal and abnormal. Consideration is given to direct connections and connections through generator breakers and load-break switches. Both hydroelectric and thermal electric generating stations are covered. Phasing procedures, basic impulse insulation-level selection, and loading practices are not covered.