Transformer Pad 5

[jolougarcia]

We're about to design a transformer pad we're a first timer in designing on this kind. Can anyone tell us how? and is there any useful article we can read? thanks.

 

[dhengr]

Jolougarcia:
You’ve given way to much important design info. The one in my front yard is molded fiberglas, with a hole in the middle for the buried cables to pass through. Then they just plunk the transformer down on it, make the connections and lock the lid. Shouldn’t involve more than a week of serious Structural Engineering.

 

[jolougarcia]

thanks sir dhengr. do you actually mean that we don't really have to design it structurally? What do you mean to make the connections and lock the lod? thanks again.

 

[CELinOttawa]

The base preparation is far more important than anything else. Remove LL organic material, compact to 95% modified proctor density.

 

[rowingengineer]

dhengr,
That is one hell of a curve ball.

Jolougarcia,
Please give us some idea of what you are designing, "transformer pad" means very little to us. is this s concrete slab, is it on ground or??? does it have feet or is it on a sled?

http://www.nceng.com.au/

"Programming today is a race between software engineers striving to build bigger and better idiot-proof programs, and the Universe trying to produce bigger and better idiots. So far, the Universe is winning."

 

[DamsInc]

Might need to consider using GFRP instead of steel bars depending on the type of transformer.

 

[ztengguy]

Also check for Dynamic loads, from the movies, those transformers change pretty quick, so I could see some impact loading from the moving parts.

 

[EngineeringEric]

ztengguy, If a non-transforming transformer should it be designed per AT/FP explosions as well? I mean based on movies these things emit fireworks and cause explosions often.

Agree with others, if it is a slab it is all just a slab design and not too sure what else there is to it. Typical loads and geometric requirements should just be worked out but there is not too much. I would talk to your transformer manufacturer for their typicals and what they like to see.

 

[DamsInc]

Also, if the transformer is oil filled, you may need to design the foundation as a containment structure.

 

[JedClampett]

Here's the steps I would follow. You'll find that they work well.
1) Ask a vague, open ended question to a website visited by a lot of experienced engineers who have very little patience for vague, open ended questions.
2) Wait for the fun to ensue!

 

[TehMightyEngineer]

In his defense I think he/she is just looking for reference material.

Maine EIT, Civil/Structural.

 

[dhengr]

Jolougarcia:
I was pulling your leg, in the hopes of getting you to think a little. You do have to use some engineering experience and judgement to design almost anything meaningful and useful to the world. And, if you ask your question on a forum, the way you did, there are many answers, you have to give use some clues if you want meaningful answers. We can’t see it from here. Talk with the transformer manufacturer about what they expect in the way of a foundation. What size is it and what does it weigh in operation? What are the soil conditions? Is this a large transformer at a power plant, a couple hundred tons maybe; a smaller transformer at a sub-station? The one in my front yard steps down the voltage from a main power line and serves six houses.

 

[cvg]

just order one pre-cast. check the yellow pages for your local pre-caster

http://www.jensenprecast.com/Electrical/Pads-p4250/

 

[JStephen]

The other extreme:

https://www.youtube.com/watch?v=Gx8KJ8cu614

 

[dik]

Can you tell us the weight and size and how much transformer oil is present?

They can be small 'plastic' pad mounted to very large ones. One transformer yard I did had four 400,000 lb transformers with 24,000 L of coolant oil each. It was supported on a structured slab with 6 auger piles and had containment.

Dik

 

[racookpe1978]

Oh man!

"Now" you did it!

Gee, you actually asked how big the transformer was, whether or not it was filled with oil, and whether or not it needed a oil-soak leak reservoir! Cripes. You'd think any of "that" was important or something. /sarchasm. 8<)

By the way.

Fire stop/fire block needed between the transformer and adjacent components?
What electrical requirements for standoff-distance, cable supports and cable tower foundations?
Movement railways or guides to roll the transformer?
What electric standoff/insulation distances do you need?
How are you going to get the rainwater/floodwater drained out of the oil-seep reservoir?
How are you supporting the fire prevention spray lines needed around the transformer? (I had to do that "little" job one time - hard when all you have is a 8 inch curb to mount a 40 foot pole.)

 

[IFRs]

You guys are way to kind, or you have time to kill. IMHO, this thread should be one post long.

 

[dik]

racook... for the rainwater/oil issue, I've used a product called sorbweb... it polymerises when subject to transformer oil and prevents passage of same, but allows rainwater to readily pass. Large containment 'pits' with the bottom portion of sorbweb. Once contaminated, it must be replaced.

Fire barriers are another neat problem...

IFRs... I have some time to kill... but, not much... need more info... many little pads, it's ok to have some movement... and they are just concrete pads without foundations...

Dik

 

[oldrunner]

Is it 10 tons or 150 tons?? Are you in earthquake country? The two codes that usually control transformer foundation design is IEEE 693 and ASCE 113. You also need a geotechnical report. Make sure that you have the C.G. (x, y, and Z) of the unit. For information of good practice as well as how not to do it, read ASCE Manual 96.

The present IEEE 693 code favors embedded anchorage, but many transformer buyers are using post installed anchors. Some require that the anchors be undercut and some require that there can be no tension in the anchor - which may mean that the transformer manufacture has to spread out the anchor spacing.


Good luck.

 

[fel3]

Some utility companies, such as Pacific Gas & Electric, which serves my area of California, already have ready-made transformer pad designs for a large number of transformer sizes as well as pad designs for master meter assemblies, etc. YOu might want to check with your local utility.

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"Is it the only lesson of history that mankind is unteachable?"
--Winston S. Churchill