- Hot search：
IEEE Std C57.12.70-2020 pdf free download
IEEE Std C57.12.70-2020 pdf free download.IEEE Standard for Standard Terminal Markings and Connections for Distribution and Power Transformers.
7.1.3 Phasor group designation for three-phase transformers
The phasor grouping of a wye, delta or zigzag connected three-phase transformer shall be indicated by the uppercase letters Y. D. or Z for the high-voltage windings and lower case letter of y. d. or z for the low or intermediate voltage windings. The phasor grouping shall be listed from high voltage to low voltage. If a neutral point is externally available, the phasor grouping for the voltage set shall end with an uppercase N or lowercase n as appropriate for the winding voltage level. For an auto connected transformer, the symbol of the lower voltage winding is replaced with the letter ba for auto. If a transformer is specified with a reconfigurable winding connection (as either dual voltage or dual phase displacement) then the initial connection for service shall be the main phasor group, with the alternative connection (voltage and/or phase displacement) noted in parenthesis.
The phasor grouping can be further described by designating the angular displacement. The angular displacement of a polyphase transformer is the phase angle expressed in degrees between the line-to-neutral voltage of the reference identified high-voltage terminal l-I and the line-to-neutral voltage of the corresponding identified low-voltage terminal Xi, The angular displacement may be from 00 to 3300 j steps 01300. The angular displacement number refers to the phase angle, as viewed on a 12 hour clock. For example, one o’clock is 30°, two o’clock is 60°. etc. This is sometimes referred to as bclock number notation”, and is intended to be the same format as used in IEC 60076-1. The phasor group designation (sometimes referred to as “vector group”) is the combination of the phasor grouping and the angular displacement.
Many transformer product standards specify that the angular displacement between high-voltage and Low- voltage phase voltages of three-phase transformers with or Y-Y connections shall be zero degrees as shown in Figure 14, Group 1. The corresponding phasor group designation would be DdO or YyO. respectively.
If the angular displacement between high-voltage and low-voltage phase voltages of three-phase transformers with -Y or Y-A connections shall be 30°, with the low voltage lagging the high voltage as shown in Figure 14, Group 2, then the corresponding phasor group designation would be Dyl or YdL, respectively.IEEE Std C57.12.70-2020 pdf free download.
All resources on this website are from the Internet. It is only for personal study and research. No one is allowed to use it for any commercial purpose. If you need, please buy the genuine standard. If there is any infringement of your copyright, please contact the webmaster in time, and I will correct it immediately.
- Maybe you like
- Latest Updates
- ISO 287-2009 pdf free download
- ISO 527-5-2009 pdf free download
- ISO 659-2009 pdf free download
- ISO 660-2009 pdf free download
- ISO 712-2009 pdf free download
- ISO 725-2009 pdf free download
- ISO 730-2009 pdf free download
- ISO 927-2009 pdf free download
- ISO 2041-2009 pdf free download
- ISO 3040-2009 pdf free download
- ISO 3506-2-2009 pdf free download
- ISO 3506-3-2009 pdf free download