Voltage Transformer name plate 2

[iphapppi]

I have a voltage transformer name plate said

6,3/√3 / 0.11/√3 / 0.11/3
0.2/3P / 40/30 kVA

can someone explain about this values?

thank you

 

[DTR2011]

The first set of values are voltages, given first in Line to Line, then √3 to denote the Line to Neutral Voltage.

So 6.3kV/√3 = 3.637 kV on the primary. The same applies for the secondary voltages, here also expressed in kV.

.110 kV = 110 V/√3 = 63.51 V. These are pretty standard secondary ratings for PT.

The reason for the 0.11/√3 / 0.11/3 listing is that the PT has 2 secondary windings, which is fairly common. Do I read correctly that the second winding does not have "√3" attached to it?

This is an IEC PT, so I will guess that the 0.2/3P is 0.2 = metering accuracy and the 3P is the protection accuracy.

The 40/30 kVA, would require a little more investigation as the numbers don't appear to add up for a 3 winding device. Perhaps it is intended for secondary windings only.

I would look for the manufacturers data sheet to confirm the kVA ratings and the lack of √3.

 

[iphapppi]

thanks a lot for your explanation smallgreek
I'm pretty sure that the name plate say 110/√3 / 110/3
that's what confuse me, is it the secondary voltage too? but why 110 / 3 instead of 110 / √3
it is uncommon value of secondary voltage.
I couldn't find the manual book, and by the way it is chinese PT

 

[mgtrp]

Is the second winding meant for a broken delta connection perhaps? That could explain the sqrt(3).

 

[iphapppi]

Can you explain more about this broken delta connection? what's the purpose and I still not clear about the 110/3 V
thank you very much

 

[mgtrp]

It's used for detecting earth faults on impedance- or un-earthed systems. During a phase-earth fault, the voltage developed across the broken section of the broken delta would be 110V on a 6.3/sqr(3):110/3 set of VTs, or 190V on a 6.3/sqr(3):110/sqr(3) set of VTs.

See

http://www.basler.com/downloads/pc-59n01.pdf,

or google for further explanation.

 

[iphapppi]

thank you very much mgtrp for your explanation

 

[DTR2011]

I agree with mgtrp on the 3V0. What is this 110/3 winding connected to? If you can verify that it is a broken delta connection, is there a properly sized resistor in the circuit?

There is more information on the VT subject from a more IEC perspective available @

http://www.cigre.nl/media/40320/06_current-___voltage_transformers.pdf

This also explains the accuracy class, which was part of the nameplate data you listed in the first post.