zero sequence generator

[wonderchi]

Hi,

If the manufacture only provides positive sequence impedance for a 3 winding core type, 12/11/0.415kV transformer with out giving the zero sequence impedance, what approximation can I take?

Any links or doc that I can refer to will be very much appreciated.

Thanks

 

[dpc]

Depends on the connection (vector group) and which winding you are talking about.

Try a Google search for transformer symmetrical components.

 

[cuky2000]

Check the enclose links regarding zero sequence for a common transformer configuration.

http://cuky2000.250free.com/Three_Winding_Transf.gif

http://cuky2000.250free.com/Transf_Three_Winding_2.jpg

 

[Kiribanda]

wonderchi,

"..12/11/0.415kV transformer ... "

From the above voltages it sounds to me that you are in the IEC world.

Please refer to Table 1 of IEC 60076-8 for a complete list of typical zero sequence impedance values for 3-winding transformers with different connection symbols. But, if you are looking for an accurate value, the only contact is the transformer manufacturer.

Hope this helps.

Kiri