IEEE C57.12.51-2008

1 Overview
   1.1 Scope
   1.2 Purpose
2 Normative references
3 Definitions
4 Usual service conditions
5 Ratings and characteristics
   5.1 Kilovolt-ampere ratings
   5.2 Kilovolt-ampere and voltage ratings
   5.3 Taps
   5.4 Insulation levels
   5.5 Angular displacement and terminal markings
   5.6 Percent impedance voltage
6 Construction
   6.1 Insulation system
   6.2 Accessory location
   6.3 Nameplate
   6.4 Transformer connections
   6.5 Tap changing
   6.6 Lifting, jacking, and moving facilities
   6.7 Ground pad
   6.8 Transformer enclosure
7 Routine tests
8 Tolerances
9 Other ratings and characteristics
   9.1 Forced-air-cooled ratings
   9.2 40 Degree C average ambient temperature conditions
   9.3 Other winding temperature rises
   9.4 Other temperature class insulation systems
   9.5 Other high-voltage ratings and connections
   9.6 Y-Y connected transformers
   9.7 Increased neutral insulation
   9.8 Other basic lightning impulse insulation levels
10 Other construction
   10.1 High-voltage connection arrangements
   10.2 Low-voltage connection arrangements
   10.3 Surge arresters
   10.4 Unit substation application
   10.5 Temperature devices
   10.6 Forced-air cooling
   10.7 Provision for future forced-air cooling
   10.8 Space heaters
   10.9 Current transformers (or provision for their addition
         in the future)
   10.10 Terminal blocks
   10.11 Contacts
11 Other tests
Annex A (informative) Bibliography

Presents characteristics relating to performance, limited electrical and mechanical interchangeability, as well as safety of the equipment described, and to assist in the proper selection of such equipment.