ipt type="text/javascript"> (fun

1. fgm
Member

Join Date
Apr 2011
Posts
26

## How design autotransformer in ETAP?

I have autotransformer consisting of 3 single-phase auto transformers 400/220 / 31.5 kV and 267 MVA unit capacity or total capacity of 800 MVA
Modeling it with a 3-Winding Transformer , but I can't understand in the section for "impedance" resistance for a 800 MVA оr for a 267 MVA should I enter?

Last edited by fgm; 03-04-2016 at 01:10 AM.

2. Spons Circuit
Join Date
Always
Posts
Many

3. Very Active Member

Join Date
Jun 2010
Location
test
Posts
532
You need to read symmetrical components by blackburn to know the basics. You need to go back the basics of per unit calculations.

Let's always remember that:
ETAP is just a tool. A garbage input results in a garbage output.

Sent from Mars using Tapatalk

4. -

5. Member

Join Date
Oct 2014
Posts
67

Hi,

when dealing with single phase transformers to be connected to form a bank of three phase power transformer, the impedance per transformer should be used. this is independent when it is connected as an auto transformer bank. But, since the auto transformer is like a three-winding transformer, the nameplate of the transformer will have illustrated three values of impedances measured with respect to each other (i.e. H-X, H-Y, X-Y). In this case, you have to solve the value of impedance per side of transformer (H, X, Y) because these data are needed in the power flow software. the formula for that is usually written in several excellent texts in power system. In the case of PSS/E, you will have to just input the nameplate parameters and the software engine will solve the required impedances.

6. Member

Join Date
Oct 2014
Posts
67

Hi,

when dealing with single phase transformers to be connected to form a bank of three phase power transformer, the impedance per transformer should be used. this is independent when it is connected as an auto transformer bank. But, since the auto transformer is like a three-winding transformer, the nameplate of the transformer will have illustrated three values of impedances measured with respect to each other (i.e. H-X, H-Y, X-Y). In this case, you have to solve the value of impedance per side of transformer (H, X, Y) because these data are needed in the power flow software. the formula for that is usually written in several excellent texts in power system. In the case of PSS/E, you will have to just input the nameplate parameters and the software engine will solve the required impedances.

7. fgm
Member

Join Date
Apr 2011
Posts
26

Thank's.
I will use the impedance for a 267 MVA in p.u %

8. fgm
Member

Join Date
Apr 2011
Posts
26

double post

9. Very Active Member

Join Date
Mar 2016
Posts
505

[link Point to another website Only the registered members can access]

[link Point to another website Only the registered members can access]

[link Point to another website Only the registered members can access]

[link Point to another website Only the registered members can access]

[link Point to another website Only the registered members can access]

Last edited by himmelstern; 09-12-2017 at 11:05 PM.

10. Active Member

Join Date
Feb 2013
Location
algeria
Posts
168

thanks himmelstern

11. Very Active Member

Join Date
Mar 2016
Posts
505

I found an autotransformer on GIS or geoespatial diagram* for railway applications* it used for etrax module.

and

Last edited by himmelstern; 09-14-2017 at 08:06 PM.

12. Active Member

Join Date
Aug 2014
Location
Sweden
Posts
150

## Re: How design autotransformer in ETAP?

Originally Posted by fgm
I have autotransformer consisting of 3 single-phase auto transformers 400/220 / 31.5 kV and 267 MVA unit capacity or total capacity of 800 MVA
Modeling it with a 3-Winding Transformer * but I can't understand in the section for "impedance" resistance for a 800 MVA ذ¾r for a 267 MVA should I enter?
OK so 3W TX

If LV winding = 800 kva and if Teritry winding = 200 kva then HV winding will = 1000kva (sum) in most cases.
Now you must check impedance Z% from manufacturer nameplate. With Z% and kva you can calculate R* X *X/R ratio.

*very important*: depend on software make sure you calculate above values on correct base power (usually winding kva). I see many mistake from this error.

Edit: i misread your best* what i say above is for three winding transforner* autotransformer might be different.
Last edited by user82; 09-15-2017 at 08:00 PM.

13. Very Active Member

Join Date
Mar 2016
Posts
505