Power Transformer Replacement Field Testing

[trouthunter]

We are a nuclear power generating station, and will be replacing a reserve station service transformer with an auto load tap changing transformer (make and model yet to be determined). We are currently in the conceptual design stage. The old transformer (oil filled) is 115kV/4.16kV, 12.5 MVA, Y-Delta-Y. The new transformer (oil filled) will be 115kV/4.16kV, approx. 18 MVA, Y-Delta-Y. the cooling arrangement has not yet been decided. There will be limited time available for the installation and testing, including removal of the old transformer (about 20 days). Has anyone performed this type of transformer installation? If so, what type of factory and field testing did you specify (what standards)? Do you have any lessons-learned to share? The installation and testing may be performed during March/April time frame, so the weather could include freezing temperatures and/or snow.

 

[jbartos]

Suggestion: Since this is primarily Eng-tips Forum, I will address more engineering aspects only:
1. Transformer testing requirements can follow industry standards, e.g. ANSI/IEEE which the nuclear power plants often adhere to.
NETA test documents can also be adhere to since they frequently refer to ANSI/IEEE Standards.
Visit:

http://www.ieee.org

http://www.ansi.org

http://www.netaworld.org

etc. for the industry standards.
2. 18MVA transformer size will require a revision of short circuit and voltage drop calculations, and possibly the hardware adjustments.