Why Are Almost All Directional Relays Using V-Connection PT?

Measure the phase by applying a scope across the secondary side of the transformer.

Look on GlobalSpec for scopes, if you don't already have one.

And what are you talking about? The voltages you get will depend on the phasing of the line - which is not marked - and how you connect the VTs - and you have not shown any "polarity markings", thus no one knows what you might end up with on the secondary side.

Unlike some people, the voltage transformers know exactly what they are doing and their secondary voltages will be in phase with the line voltages - if properly connected.

The voltages in your drawing are not 120 degrees apart, but 60 degrees apart, . . . it is an "open delta" or "V" connection that you are showing.

Yes, the voltages at the distribution level (6.6 . . . 33kV) will be typically measured using only two VTs connected "V" because it is cheaper than having three VTs, and because the circuits at this level are typically Delta. The VTs will always be connected "Y" in higher voltage circuits . . . like 66kv . . . . 500kV.

What "unequal angular displacement" are you talking about? better explain yourself, . . . even better, read the instruction manual for a 67 Directional Overcurrent Relay.

the polartiy is there. It is subtractive this is came from Basler Electric directional relay manual.

How did you know that voltage are not 120 degree apart and it is 60degree apart? A balanced delta connected transformer has 120degree angular displacement Vab<0, Vbc<-120, Vca<120. If one transformer is removed say Vca<120 how can you prove that Vab and Vbc are 60degrees apart? Besides if you measure the voltage across the load you may get Vab=Vbc and consequenlty Vca>Vab.

If the angular displament of this voltage are not equal then I may not be able to get the required degree connection of each phases. Example the requirement is 90degree connection and 67relay has a characteristic of 30AMT.

<...that voltage are not 120 degree apart and it is 60degree apart? ...>

Because the reference point is the earth connection on the secondary.

If 60degrees apart what will be the angle of output voltages? Say Vab=16.05 Vbc=18.2 and Vca=16.87?

Oh, so those little 'slits' that I can barely see on my screen are supposed to be polarity markings - fine.

Someone should tell Basler to use 'standard conventional' markings.

Now, if you have the Basler manual - they must have an example of connecting their 67 relay to line-line connected VTs. They do have numbers on the drawing you posted, . . . so they must say where to connect the same.

I know that the voltages on the output of the VTs (as shown in your diagram) are 60 degrees because I read your diagram and assumed that the lines was labelled R,Y,B or 1, 2, 3. (no actual label on diagram).

You are using abc labels, but your diagram does not have abc labels, so why don't you use the labels that are there, . . namely 5, 11, 12. Thus voltages 5-11 and 12-11 are 60 degrees apart, but voltages 5-11 and 11-12 are 120 degrees apart. These voltages are line-line voltages, . . . and the 67 relay must be using line-ground voltages - voltages that you do not have.

Being smart, Baseler is likely generating the needed line-ground voltage from the L-L voltages by using an artificial neutral.

I believe you are totally confused be something you read and did not understand, I am certain that you do not need to generate any voltage at 90 degrees and connect same to the 67 relay (90 degrees with respect to WHAT?).

Angular displacement is not related to voltage equality.

Yes! I need the angle of voltages so i can get and analized the 90degree connection of my 67relay

The voltages (Vab, Vbc, Vca) are 120° apart. Just draw out the vectors and you will see. However, the directional overcurrent relay is only looking at the voltage that corresponds to each individual phase current, NOT all 3 voltages. These relays have been single-phase units for many years.

The ground connection can confuse a person (as PWSlack's comment showed). It is NOT the reference from which the voltages are being measured - they are defined by the vectors based on Va, Vb, and Vc. The ground reference is to keep the potential of the whole scheme from rising higher than the equipment insulation can handle.

The ANSI device 67 (directional overcurrent) looks at the phase angle between the current and the voltage to determine if it should trip. Overcurrent in one direction will give a certain phase angle, and not trip even if the current is over pickup, but in the opposite, it will trip based on the timing curves when the relay sees the voltage at the appropriate angle. The relay manufacturer has taken that all into consideration, and if you connect the relay as they specify, it WILL operate as designed.

If you want some background about how this works, see Chapter 3 in the following reference (GE's free, downloadable "The Art & Science of Protective Relaying"):

http://www.gedigitalenergy.com/multilin/notes/artsci/index.htm

As per your link it seems that the output voltages phasor diagram are still within 120degrees displacement for v connected PT.