PHASE DESIGNATION

[aishu]

We have the following requirement for phase designation for tranmission S/S :

The phases in all new substations shall be designated as R (Red), Y (Yellow) and B (Blue) throughout the substation when viewed from East to West, from North to South and from Top to Bottom. For MV switchgears phase conductors when viewed from operating side, the phase designation shall be R, Y, B from left to right, from front to back and from top to bottom.

Is there any other standard or practice for phase designation (I do not want for power transformer as we have IEC/IEEE for that)

Thanks

 

[rbulsara]

While there is no law, in the ANSI world NEMA has the guidelines as follows:

Phase A-B-C, left to right, top to bottom, and front to rear, as viewed from the front. (A-B-C would relate to R-Y-B).

NEMA also requires that units conforming to above be clearly identified as such.



Rafiq Bulsara

http://www.srengineersct.com

 

[jghrist]

Keep in mind that if you have R-Y-B East to West for a DYn1 transformer facing North and R-Y-B East to West for a DYn1 transformer facing South, you will have a 60° phase difference in the secondaries and you won't be able to get the phases correct by rolling the secondary phases.

 

[rbulsara]

I meant to say in the last line.."...units NOT conforming to....".

Rafiq Bulsara

http://www.srengineersct.com

 

[stevenal]

If these substations have or will have transformers, and you standardize on a single DY polarity group; you will have problems sticking to this scheme. I know of a utility who uses ABC N-S and E-W, and they use reconfigurable transformers to make it work. In contrast, our practice is to hit the substation so that ABC will hit H123 no matter what the compass reads. Transformers are all ANSI standard, and can be moved from place to place in the system with no reconfiguration or rolling of phases needed.

 

[rbalex]

For US domestic facilities the basic rule for enclosed equipment (Switchboards and Panelboards) is documented in NEC-2008, Section 408.3(E). It is repeated in Sections 409.102(B) and 430.97(B) for Industrial Control Panels and Motor Control Centers respectively.

 

[resqcapt19]

Bob,
The rules in the NEC don't really seem to mean anything based on this proposal for the 2011 code.

_______________________________________________________________
9-139 Log #3652 NEC-P09 Final Action: Reject
(408.3(E))
_______________________________________________________________
Submitter: Donald A. Ganiere, Ottawa, IL
Recommendation: Revise text to read as follows:
(E) Phase Arrangement. The phase arrangement on 3-phase buses shall be so
that when the leads of a phase rotation meter are connected A, B, C from front
to back, top to bottom, or left to right, as viewed from the front of the
switchboard or panelboard that the phase rotation meter shall indicate a
clockwise rotation. The B phase shall be that phase having the higher voltage
to ground on 3-phase, 4-wire, delta-connected systems. Other busbar
arrangements shall be permitted for additions to existing installations and shall
be marked.
Substantiation: As this section is currently written it has no meaning. It
appears that the intent is to require a clockwise rotation. If this is not the intent,
then the section does not accomplish anything as the terms A, B and C are only
arbitrary terms and the section should be deleted from the code.
Panel Meeting Action: Reject
Panel Statement: 408.3(E) is intended to be a construction requirement for
panelboards and switchboards as a matter of consistency. The proposal is a
design consideration for connected equipment which is not the purpose of this
section.
Number Eligible to Vote: 12
Ballot Results: Affirmative: 12

Don

 

[stevenal]

OP was about a transmission substation, not a panelboard. Wrong code section in the wrong code.