Simple question about vector group YnD11 ?
Simple question about vector group YnD11 ?
(OP)
Friends,
I have a question about vector group YnD11.
If we assume current flows from primary to secodary, angles will be Y (0°) - D (30°).
But if current flows secondary to primary , which angles will occur ? Y (30°) - D (0°)?
Thanks for your time.
I have a question about vector group YnD11.
If we assume current flows from primary to secodary, angles will be Y (0°) - D (30°).
But if current flows secondary to primary , which angles will occur ? Y (30°) - D (0°)?
Thanks for your time.






RE: Simple question about vector group YnD11 ?
RE: Simple question about vector group YnD11 ?
RE: Simple question about vector group YnD11 ?
Upper case letters indicate HV connections, lower case letters indicate LV connections. I can guess that the 'n' is associated with the star winding but I don't know which winding is the HV winding because your designation is incorrect.
RE: Simple question about vector group YnD11 ?
RE: Simple question about vector group YnD11 ?
In any '11' configuration the LV winding leads the HV winding by 30°. In a YNd11 transformer the delta winding leads the star winding by 30°, so if you use the delta winding as the reference then the star winding has a 30° lag.
RE: Simple question about vector group YnD11 ?
When we get Delta as reference , Y leads 30 degree.
So if delta winding is 0 degree, Y winding is +30 degree.
This is the problem.
RE: Simple question about vector group YnD11 ?
The standard test usually links the A and a terminals then applies a suitable (safe) test voltage to the HV winding, and the resulting voltages between terminals prove the vector group. The relative magnitudes are more important than the actual values. The procedure and interpretation of results are well-documented.
RE: Simple question about vector group YnD11 ?
RE: Simple question about vector group YnD11 ?
RE: Simple question about vector group YnD11 ?
RE: Simple question about vector group YnD11 ?
See Figure 15 on page 15 (pdf 17).
RE: Simple question about vector group YnD11 ?
I m at powerplant now, Combined Cycle Power Plant.I drawed the single line and CT polarity to paint.
The reason that I asked you , I m configurating GE T60-U Block-Unit Differential Relay.
Thank you.
RE: Simple question about vector group YnD11 ?
RE: Simple question about vector group YnD11 ?
Delta is Generator Side , 15750 V side
Y is 400 Kv Side , 400 kV Side
Dont mind the DYn1 transformer, just consider Gen+Transformer (YnD11)
RE: Simple question about vector group YnD11 ?
RE: Simple question about vector group YnD11 ?
If the current into the delta side of the Ynd11 transformer is at angle 0°, then the current out of the wye side will be -30°. Current into the wye side is 180° from current out of the wye side, so it is at an angle of +150°.
RE: Simple question about vector group YnD11 ?
Please check values than you will understand my point.
I will attach here my protection relay set screen .
And the values which I injected as secondary are like below;
Gen Side : HV (Y Side)
I1: 0,083 0° I1: 0,083 -150°
I2: 0,083 -120° I2: 0,083 -270°
I3: 0,083 -240° I3: 0,083 -30°
At the values, Relay dont trip. There is balanced and no differential .
According to jghrist and all informations which i know, It should be -30° ,not -150°.
RE: Simple question about vector group YnD11 ?
RE: Simple question about vector group YnD11 ?
We can understand the polarity just from connections.There s no setting.Because of this ,I need to consider all CT polarities which are related.
RE: Simple question about vector group YnD11 ?
RE: Simple question about vector group YnD11 ?
RE: Simple question about vector group YnD11 ?
Using two captial letters makes this really confusing, but if the delta is the generator LV side we call this a YNd11
The d side is at +30 degrees when compared to the Y side reference, (or -330 deg or 11 o'clock)
So conversely the Y side is at -30 degrees if the d side is the reference which is what you are doing (or 1 o'clock)
You then need to add 180 degrees for the relay measurement (-30 + 180 = +150 degrees)
In the setting file, the delta side has been entered as the reference, the Y side is at -30 degrees to the reference, so the setting in the T60 should be -30.
For conventions, we normally connect the HV side as winding 1 and the LV side to winding 2, if you did this the setting would be -330 degs (or 11 o'clock).
Either way works, but I find this easier to follow.
RE: Simple question about vector group YnD11 ?
Can you look at the pic on attachment? I added my software pic during injection test.
At these conditions ,there s no trip. Primary Side is GEN side, I mean delta side is reference(This is my transf. Ynd11 but I use it reverely) .
RE: Simple question about vector group YnD11 ?
RE: Simple question about vector group YnD11 ?
RE: Simple question about vector group YnD11 ?
RE: Simple question about vector group YnD11 ?
The injection angles look correct for the settings shown in your T60 screenshot.
The relay has been set so the Wye side is as -330° with respect to the delta reference (or the Y side is at +30° with respect to the delta side).
However for a Yd11 transformer, the Wye side lags the delta side by 30° (or the Y side is at -30° with respect to the delta side)
If you are injecting at 180°,60°,-60° on the generator (delta) side, the angles on the Y side should be -30°,-150°,90° for a Yd11 Transformer.
I am not sure that the settings are correct for a Yd11.
RE: Simple question about vector group YnD11 ?
I called engineering center many times,They said settings are correct and said "We make these settins always,no problem".Bu I dont trust them, of course.
Then...
I disable the diffferential protection .
I energized the Step-up Tranf and Unit Auxiliary Transf. .Then I put some loads.
Finally , I saw the angle differences,The settings was not correct as you said.
I fixed settings as me and you know, like " gen : 0 , hv : -30 , uat : -30 " respectively.
Thank you again.
RE: Simple question about vector group YnD11 ?
RE: Simple question about vector group YnD11 ?
RE: Simple question about vector group YnD11 ?
From;
http://electrical-engineering-portal.com/understan...
Winding connection designations
First Symbol: for High Voltage: Always capital letters.
D=Delta, S=Star, Z=Interconnected star, N=Neutral
Second Symbol: for Low voltage: Always Small letters.
d=Delta, s=Star, z=Interconnected star, n=Neutral.
Third Symbol: Phase displacement expressed as the clock hour number (1,6,11)
Example – Dyn11
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Simple question about vector group YnD11 ?
RE: Simple question about vector group YnD11 ?
The points that I was making was that the high voltage winding is used rather than the primary winding, and the convention concerning capitalization.
Bill
--------------------
"Why not the best?"
Jimmy Carter