IEEE Std C57.129:1999 pdf free download

IEEE Std C57.129:1999 pdf free download.IEEE Trial-Use Standard General Requirements and Test Code for Oil-Immersed HVDC Converter Transformers.
5.1.5 Direction of power flow
Unless otherwise specified. converter transformers shall be designed for both rectifier and inverter operation.
5.2 Loading at other than rated conditions
Loading above the nameplate is not a normal pail of converter transi rmer loading. Converter transformers are normally designed 11w a specilic dc terminal and are coordinated with the capabilities of the valves and other dc components.
If the terminal is to be operated above rated capacity. a detailed thermal study is needed to determine the capability of all the affected terminal equipment. Detailed information about the translormer design and capabilities at both fundamental and harmonic currents should be part of the study.
5.3 Unusual service conditions
Conditions other than chose described in 5.1 are considered unusual and should be brought to the attention of those responsible br the design and application of the apparatus.
5.3.1 Unusual temperature conditions
Loading over the full range of ambient temperatures at a given terminal should be part of the transformer design study. Standard tables should not be used for converter transformers because of the effects of harmonic currerns and the dc bias on the valve winding(s).
5.3.2 Unusual altitude conditions
The dielectric strength. which depends in whole or in part on air for insulation, decreases as the altitude increases due to the effect of decreased air density. When specified. converter transformers shall be designed with larger air spacings using the correction factors presented in Table I of IEEF. Std C57.12.00-1993 to obtain adequate air dielectric strength at altitudes above l00 m (3300 ft).
5.3.3 Other unusual service conditions
Unusual service conditions are described in 4.3.3 of IEEE Std C57.1200-1993. Note that for converter transformers pollution aspects are extremely important and shall be accurately defined so that proper external insulation (particularly bushings) may be provided. In addition to the factors listed in IEEE Std C57. 12.00-1993, dc currents caused by geomagnetic storms are considered as unusual service conditions.
6. Rating data
6.1 Cooling classes of converter transformers
Cooling classes ot converter transt1wmcrs are dctincd in 5.1 of IEEE Std C57. 12.00-1993.