Tranformer operating costs

[HamidEle]

I am doing the transformer operating cost comprison. A transformer loss is 18KW. B transformer loss is 20.5kw. Cost effciency factor is $2500/kW. Operating time per year is 8000Hours. The operating cost difference is 2.5x2500x8000=$50,000,000. Does it make sense? Sounds unbeliable!!
It does not make much sense to me.

 

[jghrist]

What is "cost efficiency factor"? Transformer loss evaluation uses two factors, one is the cost/kW of load losses and one the cost/kW of no-load losses.

To get the present worth of operating cost difference over the life of the tranformer, multiply each loss difference by the appropriate factor and add them together. You don't multiply by hours.

 

[wolf39]

For cost evaluation purposes the utility tells the transformer bidders what additional costs will be added to the various transformer prices. You name a loss evaluation of $2500/kW. In reality such figure is higher for the no-load loss portion as these losses are present all the time of operation.

The utility arrives at the loss evaluation figure by multiplying the revenue per kWh (lets assume $0.025 per kWh) with the operation hours per annum over the transformer life time. In your case we get 0.025 x 8000 x 30 years = $6000/kW for the no-load losses. The load loss figure in such case may be in the region of $3000 per kW.

Such loss evaluation enables the utility to decide on the most economical bid. A transformer with a high price tag may be the more economical one in the long run if the losses are lower compared with the cheaper competitors.

The above loss evaluation figures may be quite conservative as nobody can tell us how the revenue per kWh will develop over the next 30 years.

Regards

Wolf

http://WWW.HYDROPOWER-CONSULT.COM