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115-12kV Transformer Loss Calculations

115-12kV Transformer Loss Calculations

115-12kV Transformer Loss Calculations

(OP)
I'm looking for some ballpark values for No-load and Load loss ($/kW) values for 115-12kV transformers.  Using the IEEE C57.120-1991 method, I have ended up with about $4600 and $2500 respectively.  Using another method, I have ended up with about twice that.  

While the "twice" values seem high, I also trust the calculation methods more (as they are easier to understand).

Anyone have experience in whether either of these are in the right "ballpark"?  I know that they will differ some based on per kW cost of energy and other costs, but the ballpark should be similar I would think...

Thoughts?  Thanks in advance...

RE: 115-12kV Transformer Loss Calculations

(OP)
What other information do you need?  I'll try to provide more if you have a specific question.

Just kind of looking compared to "averages" that other companies have used as to whether either of them is high, low, or in the ballpark.  

 

RE: 115-12kV Transformer Loss Calculations

Seems a little on the low side, but it could be correct.  Too many variables and assumption go into that number to be very specific.  

Assumed cost of money, inflation, load factor, years of service, electric rates, etc all have a big impact.  

 

David Castor
www.cvoes.com

RE: 115-12kV Transformer Loss Calculations

overvolage:

If you want to verify your calcs, post your calcs, input data and related  assumptions you might have made. Not that that is what this site is for.

US or Australian dollars would also make a difference for starters.

Rafiq Bulsara
http://www.srengineersct.com

RE: 115-12kV Transformer Loss Calculations

Overvoltage : As you have seen in C57.120,the calculated loss capitalisation values can differ a lot depending on the assumptions taken.I think the values you got by C57 are quite reasonable and agrees with market situation.What was the alternate method followed  by you ?

I found the method followed by RUS is a bit more convenient and logical.Please give a try and let us know the results.

http://www.usda.gov/rus/electric/bulletins.htm  

RE: 115-12kV Transformer Loss Calculations

(OP)
Thanks for all of your help.  Ended up going with a blend of the IEEE and RUS numbers as they ended up pretty close.  That, and we were able to get some numbers to compare to, which they also agreed with.   

RE: 115-12kV Transformer Loss Calculations

When we surveyed other utilities in our area about 10 years ago, costs ranges were 2350-7127 and 700-3600.  Our recent numbers are in the range of 8600 and 4800 for that type of transformer.  Our 230 kV to 115 kV and 12 kV to 120/240 V transformers have much different loss values based on different loading profiles.

RE: 115-12kV Transformer Loss Calculations

What demand and energy cost did you use to get the $4.60/W and $2.50/W?

What loss factor and peak loading values were used?

Feeling comfortable with what others are using may provide some comfort but if your energy costs are significantly different then your A and B factors will be significantly different too.

I wouldn't think the IEEE and RUS numbers would be too close since the RUS has a lower cost of money than IOUs and they don't pay Federal income tax.

As Rafiq and dpc suggests, post your assumptions or be happy with what you have.

 

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