Parameter of 3 windings transformer
Parameter of 3 windings transformer
(OP)
Anyone familiar with Neplan? I got a 3 windings transformer rated at
1. 7.6/6.8/0.8MVA,
2. 18/11/0.415kV,
3. Uk(H/X)=12% to 6.8MVA base
4. Uk(H/Y)=5% to 0.8MVA base
5. Uk(X/Y)=7.5% to 0.8MVA base
May i know how to translate this to
Rated power in MVA.
12: primary-secondary,=6.8?
23: secondary-tertiary,=?
31: tertiary-primary.=0.8?
Rated positive sequence short-circuit voltage with
respect to Sr12, Sr23, Sr31 and Ur1, Ur2, Ur3.
12:primary-secondary,= ?
23: secondary-tertiary,=?
31: tertiary-primary.=?
1. 7.6/6.8/0.8MVA,
2. 18/11/0.415kV,
3. Uk(H/X)=12% to 6.8MVA base
4. Uk(H/Y)=5% to 0.8MVA base
5. Uk(X/Y)=7.5% to 0.8MVA base
May i know how to translate this to
Rated power in MVA.
12: primary-secondary,=6.8?
23: secondary-tertiary,=?
31: tertiary-primary.=0.8?
Rated positive sequence short-circuit voltage with
respect to Sr12, Sr23, Sr31 and Ur1, Ur2, Ur3.
12:primary-secondary,= ?
23: secondary-tertiary,=?
31: tertiary-primary.=?






RE: Parameter of 3 windings transformer
Z12=12%
z23=7.5%
Z13=5%
RE: Parameter of 3 windings transformer
So, check the transformer test report to make sure.
RE: Parameter of 3 windings transformer
z12(7.6) 0.05pu 5%
Z13(7.6) 0.0003pu 0.03%
z23(7.6) 0.0004pu 0.04%
RE: Parameter of 3 windings transformer
RE: Parameter of 3 windings transformer
RE: Parameter of 3 windings transformer
Voltage where? On the unfaulted winding?
You'll have to convert the winding-to-winding impedance figures to an equivalent star circuit. With a little simultaneous linear equation chicken scratch on the back of an envelope, I get:
Zh-o = 0.0475 pu
Zx-o = 0.0725 pu
Zy-o = 0.0025 pu
Now, for a source of 1.0V pu on H and a balanced fault on X,
the voltage on the unfaulted winding, Vy is:
Vy = Vh ( Zh-o / ( Zh-o + Zx-o ) ) = 0.604 pu
Hint: If you draw the one-line diagram for the fault, it looks like a simple voltage divider.
If this is NOT what you were after, then ignore everything I've said.
RE: Parameter of 3 windings transformer
Z=Zpu1*Zb1=Zpu2*Zb2 Z=U^2/S
Zpu2=Zpu1*(Ub1^2/Sb1)/(Ub2^2/Sb2)
If the impedance in pu it's higher or lower depends of U^2/S ratio
Anyway, I think those values are odd, so maybe the Uk given are not in the base you are saying
RE: Parameter of 3 windings transformer
We used to use these in remote substations: the third winding was for station power.
As far as the Z calcs go, these other guys are right on.
Steve
RE: Parameter of 3 windings transformer
3. Uk(H/X)=12% to 6.8MVA base
4. Uk(H/Y)=5% to 0.8MVA base
5. Uk(X/Y)=7.5% to 0.8MVA base
I thought the "to" was the base of the impedance after the pwrtran post.
I think that my first post is the right one
RE: Parameter of 3 windings transformer