×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Simple question about vector group YnD11 ?

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.

RE: Simple question about vector group YnD11 ?

Are we talking about Dyn11 or YNd11?

RE: Simple question about vector group YnD11 ?

(OP)
ScottyUK , we re talking about YnD11.

RE: Simple question about vector group YnD11 ?

OK, but that isn't a recognised transformer designation. If you insist on talking about YnD11 then good luck because it's pretty meaningless.

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 ?

(OP)
I know YnD11 means.and designation is ok.Y is HV side. I know normal conditions about vektor groups and angle differences.But if we assume that we will use D as a primary-as a reference , what would Y angle be?

RE: Simple question about vector group YnD11 ?

I'm sure you won't mind if I stick to the standard winding designations in IEC 60076-1.

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 ?

(OP)
ScottyUK ..I mind your data.and I have many standarts and designations..But pratically when we re injection voltage, values are not as same as your or mine idea.

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 ?

I'm not sure where that leaves us. It isn't a YnD11 transformer?

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 ?

(OP)
ScottyUK thanks for your.time...I think I will call the manufacturer

RE: Simple question about vector group YnD11 ?

Ok, let us know how things turn out. Good luck.

RE: Simple question about vector group YnD11 ?

(OP)
Much thanks again.

RE: Simple question about vector group YnD11 ?

Link

See Figure 15 on page 15 (pdf 17).

RE: Simple question about vector group YnD11 ?

(OP)
stevenal I have that document .And I ve checked already.But It is not my answer.If you have time,can you check the file which is on attach.
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 ?

On your diagram, which side of the YnD11 transformer is Y? You are confusing the relay configurations by including two transformers. There could be different current angles even if both transformers were YY0 because of differences in load angles.

RE: Simple question about vector group YnD11 ?

(OP)
Yeah you re right. :)

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 ?

The apparent power into a transformer will be close to the apparent power out of a transformer. The voltages will lag like what you said and the power flow will still be in the same power quadrant. If the currents were leading the voltages on the generator side by 30 degrees, the currents will lead the voltages close to 30 degrees on the high side (minus vars loss exciting the transformer). You will see the same if power is flowing the other way. This for for balanced load. For unbalanced load or faults, remember the negative sequence phase shift through the transformer is the opposite of the positive sequence phase shift.

RE: Simple question about vector group YnD11 ?

Reference stevenal's Figure 15. Voltage on the wye side (1U) lags the voltage on the delta side (2U) by 30°.

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 ?

(OP)
HamburgerHelper and jghrist , thank you for you time and interest.I know It s too simple.

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 ?

The 30 degree difference will look like +/- 150 degree difference if the CTs are not facing the same direction. Draw out the vectors and you'll see why it looks the way it does. SEL relays have a polarity setting. GE relays might have this setting. If it does have this setting, you might have programmed it to work correctly but don't realize that the relay acts on the angle difference due to the CT polarization and transformer connection.

RE: Simple question about vector group YnD11 ?

(OP)
Thanks ,I got you. But GE relays has no polarity setting.
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 ?

Your settings show the GSU high side wye winding at -330° (same as +30°). A Ydn11 transformer will have the wye winding -30° compared to the delta winding. Your settings show a third winding, but your one-line doesn't show a three-winding transformer. If your injected currents are into the relay on both sides, then it matches the relay settings for windings 1 & 2, but does not match a through fault for a Ydn11 transformer. As noted in my earlier post, the current into the transformer will be at +150°, not -150°, for a through fault.

RE: Simple question about vector group YnD11 ?

(OP)
Third windng is the Y side of DYn1 transformer.

RE: Simple question about vector group YnD11 ?

I believe for that diagram the expected current angle is +150 degrees for Ia on the 400kV side when Ia on the generator side is at zero degrees.

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 ?

I am getting an error message opening the file ?

RE: Simple question about vector group YnD11 ?

Probably the ? marks in the file name are causing an issue.

RE: Simple question about vector group YnD11 ?

Hi Rayas

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 ?

(OP)
Friends ,Thank you for your interest and your time.

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 ?

Thanks for the update Rayas - a primary test is always a pretty reliable second opinion !

RE: Simple question about vector group YnD11 ?

(OP)
Yes, excatly.Thanks to all guys who helped me.

RE: Simple question about vector group YnD11 ?

This may clear up the misunderstanding as to vector group nptation;
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 ?

Typically Y/y for wye rather than S/s for star; per the example given. winky smile

RE: Simple question about vector group YnD11 ?

Agreed David. Thank you for heading off another potential misunderstanding.
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

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources