Typical Values on Losses & Impedances of Distribution Transformers

[GRAEE]

Hello everyone!

Im specifying the losses and impedance of a distribution transformer. I believe that all these parameters are affected by the efficiency being specified as well.

In this regard, can you provide me a table on typical values of impedances & losses of distribution transformers? I will use this as my reference.

Regards,

GRAEE

 

[rbulsara]

Try Google and websites of some leading transformer mfrs.

Rafiq Bulsara

http://www.srengineersct.com

 

[jghrist]

The efficiency is determined by the losses. You don't want to specify both. Understand also that if you specify efficiency, you need to state at what loading the efficiency is calculated.

If you have a concern about voltage regulation, you might want to consider specifying a maximum impedance. If you have a concern about fault current, you might want to consider specifying a minimum impedance.

You might also want to consider evaluating load and no-load losses instead of specifying either losses or efficiency.

In addition to searching manufacturers' sites, see NEMA TP-1 Guide for Determining Energy Efficiency for Distribution Transformers at

http://www.nema.org/stds/tp1.cfm

Also US Dept of Energy
Title 10: Energy
PART 431—ENERGY EFFICIENCY PROGRAM FOR CERTAIN COMMERCIAL AND INDUSTRIAL EQUIPMENT

http://ecfr.gpoaccess.gov/cgi/t/tex...=div6&view=text&node=10:3.0.1.4.17.11&idno=10

 

[ANDY197]

Each transformer is going to have different losses, how ever you can specified total losses or just the load loss.
If the manufacturer exceed the guarantee number then you can get some money back.( must be stated in the contract)
When you specified the impedance leave your self a room for errors because design engineer has 7% deviation from guarantee impedance....


Dan Dorian Nikelli
Test Supervisor
RB Watkins an Alstom Grid Services