1 Scope
2 Normative references
3 Definitions and letter symbols
3.1 Definitions
3.2 Letter symbols
4 General requirements-Systems and environmental data
4.1 Usual service conditions
4.2 Loading at other than rated conditions
4.3 Unusual service conditions
4.4 Environmental impact
4.5 Synthetic materials
4.6 Transformer oil
5 Rating data
5.1 Cooling classes of converter transformers
5.2 Frequency
5.3 Phases
5.4 Rated kilovolt-amperes
5.5 Rated current
5.6 Voltage ratings and taps for converter transformers
5.7 Connections
5.8 Polarity, angular displacement, and terminal markings
for converter transformers
5.9 Impedance
5.10 Total losses
5.11 Insulation levels
5.12 Temperature rise and loading conditions
5.13 Loss capitalization rates
5.14 Sound level limits
5.15 Auxiliary power supply voltage
5.16 On-load tap changers
6 Construction
6.1 General
6.2 Tank and component design
6.3 Oil preservation
6.4 Auxiliary equipment
6.5 Electrical connections
6.6 Nameplate
7 Tests
7.1 General
7.2 Routine, design, and other tests
7.3 Additional routine tests for converter transformers
with load tap changing or regulating transformers
8 Test code
8.1 General
8.2 Resistance measurements
8.3 Polarity and phase-relation tests
8.4 Ratio tests
8.5 No-load losses and excitation current
8.6 Impedance and load losses
8.7 Dielectric tests
8.8 Temperature rise
8.9 Short-circuit test
8.10 Audible sound test
8.11 Gas detector system operating test
9 Tolerances
9.1 Tolerance on ratio
9.2 Tolerance on impedance
9.3 Tolerance on losses
Annex A (informative) - Determination of loss adjustment factors
Annex B (informative) - Laboratory power testing concepts and
methodologies under consideration
Annex C (informative) - In-service overloading of HVDC converter
transformers
Annex D (informative) - HVDC converter transformers for use
with voltage source converters
Annex E (informative) - Design review
Annex F (informative) - Bibliography