IEEE DRAFT C57.12.01 : D6 2005

Introduction
1 Overview
   1.1 Scope
   1.2 Purpose
   1.3 Word usage
2 References
3 Definitions
4 Service conditions
   4.1 Usual service conditions
        4.1.1 General
        4.1.2 Temperature
        4.1.3 Altitude
        4.1.4 Supply voltage
        4.1.5 Load current
        4.1.6 Operation above rated voltage
        4.1.7 Location
        4.1.8 Step-down operation
        4.1.9 Tank or enclosure finish
   4.2 Unusual service conditions
        4.2.1 General
        4.2.2 Ancillary components
        4.2.3 Unusual loading
        4.2.4 Unusual altitude service conditions
        4.2.5 Insulation at high altitude
        4.2.6 Other unusual service conditions
5 Rating data
   5.1 Cooling classes of transformers
   5.2 Frequency
   5.3 Phases
        5.3.1 General
        5.3.2 Scott or T-connected transformers
   5.4 Rated kilovolt-amperes
        5.4.1 General
        5.4.2 Preferred continuous kilovolt-amperes
   5.5 Voltage ratings and taps
        5.5.1 General
        5.5.2 Voltage rating
        5.5.3 Rating of transformer taps
   5.6 Connections
   5.7 Polarity, angular displacement, and terminal marks
        5.7.1 Polarity of single-phase transformers
        5.7.2 Angular displacement between voltages of windings
              for three-phase transformers
        5.7.3 Terminal marking
   5.8 Impedance
   5.9 Losses
        5.9.1 Accuracy required for measured losses
   5.10 Insulation levels
        5.10.1 Line terminals
        5.10.2 Neutral terminals
        5.10.3 Insulation tests
        5.10.4 Taps
   5.11 Temperature rise and insulation-system capability
        5.11.1 Life of insulating materials
        5.11.2 Classification of insulation systems
        5.11.3 Limits of temperature rise for continuously
               rated transformers
        5.11.4 Conditions under which temperature limits apply
        5.11.5 Reference temperature for efficiency, losses,
               impedance, and regulation
   5.12 Nameplates
        5.12.1 General
        5.12.2 Nameplate information for ventilated and
               non-ventilated transformers
        5.12.3 Nameplate information for sealed transformers
6 Construction
   6.1 Tank-pressure requirements
   6.2 Finish of tank or enclosure
   6.3 Handling provisions
   6.4 Transformer accessories
   6.5 Terminals
   6.6 Grounding
        6.6.1 Transformer grounding
        6.6.2 Grounding of core
   6.7 Shipping
7 Short circuit characteristics
   7.1 General
   7.2 Transformer categories
   7.3 Short-circuit current duration and magnitude
        7.3.1 General
        7.3.2 Duration of short circuit tests
        7.3.3 Short-circuit current magnitude
        7.3.4 Stabilizing winding
        7.3.5 Dry-type autotransformer winding
        7.3.6 Short-circuit-current calculations
   7.4 System zero-sequence data
   7.5 Application conditions requiring special consideration
   7.6 Components
   7.7 Base kilovolt-ampere rating of a winding
        7.7.1 Base rated kilovolt-amperes of a winding
        7.7.2 Base current of winding without autotransformer
              connections
        7.7.3 Base current of winding with autotransformer
              connections
   7.8 Effects of temperature on transformer windings during
        short-circuit conditions
   7.9 Temperature limits of transformer for short-circuit
        conditions
   7.10 Calculation of winding temperature during a short
        circuit
8 Testing and calculations
   8.1 General
   8.2 Test classifications
   8.3 Routine, design, and other tests for transformers
   8.4 Calculations
9 Tolerances
   9.1 Ratio
   9.2 Impedance
   9.3 Losses
10 Connection of transformers for shipment

Describes electrical, mechanical, and safety requirements of ventilated, non-ventilated, and sealed dry-type distribution and power transformers or autotransformers (single and polyphase, with a voltage of 601 V or higher in the highest voltage winding).