Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here


3-winding transformer model in ETAP (impedance)

3-winding transformer model in ETAP (impedance)

3-winding transformer model in ETAP (impedance)

As you may know, in ETAP there's no a "typical data" button available when modelling a three-winding transformer. I want to model a 23/0.4/4.16 kV of 3 MVA.

Would it be ok to model three different two-winding transformer (23/0.4, 23/4.16 and 0.4/4.16 kV) in order to have typical values between sides? If not, which IEC/IEEE reference can I look to have some reference values?


RE: 3-winding transformer model in ETAP (impedance)

J&P has some values, but also explains that choices of winding arrangement and configuration can significantly change the numbers. For instance a transformer with two identical LV windings and HV-LV at 16% can be designed to have either LV-LV of 4% or 28%. Hard to define "typical"!

RE: 3-winding transformer model in ETAP (impedance)

Use of typical values for a three-winding transformer is risky because there is such a possible range. I'd try to get the transformer data from the manufacturer. I've been able to do this for some very old transformers - at least for US transformers. If this is a new transformer, ask potential suppliers to give you a ballpark quote with estimated impedances.

RE: 3-winding transformer model in ETAP (impedance)

In case of three winding transformers, test reports and GTP normally furnish three impedances - HV-LV-1, HV-LV2 and LV1-LV2. From these three impedances one can calculate H,L1 &L2 impedance values for use in short circuit current calculations.

RE: 3-winding transformer model in ETAP (impedance)

No you can't do that. I know tertiary deltas can have a range of impedances. Like what was said earlier, I have used the test reports for modeling.

If you can't explain it to a six year old, you don't understand it yourself.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


eBook - Mastering Tolerances for Machined Parts
When making CNC machined parts, mastering tolerances can be challenging. Are general tolerances good enough? When does it make sense to call out for tighter tolerances? Do you need a better understanding of fits, datums, or GD&T? Learn about these topics and more in Xometry's new e-book. Download Now
eBook – How to Choose the Correct Corrosion Testing Method
When designing a metal component, engineers have to consider how susceptible certain alloys are to corrosion in the final product’s operating environment. In a recent study by NACE (National Association of Corrosion Engineers), it was estimated that the direct and indirect costs of corrosion in the United States is approximately 6.2% of the GDP. In 2016, that cost exceeded $1 trillion dollars for the first time. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close