3 winding trafos
3 winding trafos
(OP)
Can anyone help me?
3 winding trafo: Primary: 600 MVA, 11kV
Secondary: 600 MVA, 400kV
Tertiary: 100 MVA, 11kV
There's a balanced load of 400 MVA @ .8 lagging p.f. on the secondary, which is maintained at 400kV line voltage, and a balanced load of 50 MVA at unit p.f. on the tertiary winding.
From short circuit test results, Per unit series equivalent reactances were calculated for inclusion in a single line equivalent circuit, using a 600 MVA, giving xp = j0.11, xs = -0.01j and xt= 0.85j.
I've been able to calculate the current taken by the secondary load but i'm stuck when it comes to the tertiary.
Can anyone tell me how to calculate load impedance connected to the tertiary? So that I can calculate the line voltages at the primary and tertiary windings?
Apologies if this is a silly question...
Thank you!
3 winding trafo: Primary: 600 MVA, 11kV
Secondary: 600 MVA, 400kV
Tertiary: 100 MVA, 11kV
There's a balanced load of 400 MVA @ .8 lagging p.f. on the secondary, which is maintained at 400kV line voltage, and a balanced load of 50 MVA at unit p.f. on the tertiary winding.
From short circuit test results, Per unit series equivalent reactances were calculated for inclusion in a single line equivalent circuit, using a 600 MVA, giving xp = j0.11, xs = -0.01j and xt= 0.85j.
I've been able to calculate the current taken by the secondary load but i'm stuck when it comes to the tertiary.
Can anyone tell me how to calculate load impedance connected to the tertiary? So that I can calculate the line voltages at the primary and tertiary windings?
Apologies if this is a silly question...
Thank you!






RE: 3 winding trafos
You have a T network with your 3 equivalent impedances.
o-----Xp-----0-----Xs-------0
|
|
Xt
|
|
0
I'm sure you probably calculated the secondary current and voltage based on Xp-s and Vs. If you do it with the 3 impedances, you'll get Is and It flowing through Xp. This will have an effect on both the secondary and tertiary voltage.
See if that helps.
RE: 3 winding trafos
However to calcualate rsistive load connected to the tertiary, could I assume that the load is 50MVA at 11kV?
RE: 3 winding trafos
However to calculate the resistive load connected to the tertiary, could I assume that the load is 50MVA at 11kV?
RE: 3 winding trafos
Is this a homework problem?
RE: 3 winding trafos
It's past a examination question for a taught Masters.