Transformer Seismic Qualification
Transformer Seismic Qualification
(OP)
We have a potential client that wants assistance in providing seismic calculations to qualify their transformer in a nuclear plant application. I am a little unclear (as I think they are) of what the scope of work actually is. My understanding is they are referencing IEEE standard 344 "Recommended standard practice for seismic qualification of class 1E equipment for Nuclear Power Generating Stations", this code is referenced by ASCE 7 section 9.6.1.1. In this section, ASCE 7 prescribes a static force procedure for analysis of the structure. To anyone who has performed this type of work, has your scope been limited to analyzing the transformer housing structure and providing anchorage forces, and have you used this section of ASCE 7 for analysis?
Thanks for any help you may be able to provide
Thanks for any help you may be able to provide






RE: Transformer Seismic Qualification
RE: Transformer Seismic Qualification
RE: Transformer Seismic Qualification
RE: Transformer Seismic Qualification
-Mike
RE: Transformer Seismic Qualification
RE: Transformer Seismic Qualification
In one case, the transformer was already on line and they had to shut it down, drain the oil and were able to change out some of the bracing and bolts inside the can. It gets to be fun adding in the sloshing forces.
We used Risa3d.
RE: Transformer Seismic Qualification
oldrunner, was this only a structural analysis of the transformer structure and anchorage? Does this assume if the structure remains intact then the transformer continues to operate normally?
RE: Transformer Seismic Qualification
Actually the required code was IEEE 693, "Recommended Seismic Design for Substations". You are right, zones are not really identified, but IEEE 693 has only two force levels for this type of project and California has only two different seismic zones. The project is located in Zone 3 so the lower force levels were required.
Yes, this is only for the transformer. It is interesting that California does NOT require, at least for these new plants which are using jet turbines, that the plants to be designed as "essential" facilities with the 1.5 increase.
We worked on a plant at Klamath Falls, Oregon, and Oregon DOES consider the plants as essential facilities.
Just yesterday I attended a technical meeting put on by another engineer and he brought up that point concerning California not requiring the essential facility designation for these plants.
RE: Transformer Seismic Qualification
With Respect...
RE: Transformer Seismic Qualification
0.5g and 0.25g are not extremely high seismic accelerations; my guess is your transformer should pass fairly easily.
The original post indicated this was a nuclear application, but subsequent posts seem to indicate its' a gas turbine power plant.
You should get either a seismic "shake table" test or a set of calculations by the engineering firm that use a lateral load of 0.5 x W and a vertical load of 1.25 x W to demonstrate the transformer works during/after the earthquake.
RE: Transformer Seismic Qualification
With Respect...
RE: Transformer Seismic Qualification
At least two or more of the preceeding posts have pointed you towards your answer.
More specific, review the Annex R Analysis report template in the IEE Std 693-1997, which will provide you with almost all the questions that you are asking.
An internal analysis of core coils and other components as well as the structural stability members may suprise you as to their adequacy. Some of the structural components may not work. The two different companys that I have provided analysis for only set the internals on the bottom of the tank; they are held in place laterally by studs. To resist the overturning (usually the short direction), there is some sort of bracketing to the side walls. All of this has to be analyzed and they might not be adequate as one of my customers found out. (These were using the lower seismic values!)
Until someone in your firm has actually performed at least the static analysis, you comments concerning "negligible" is possibly expressing an engineerng opinion outside of your expertise.