VT errors

[dfdt]

Can some one let me know if ratio and phase angle errors of a VT can be assumed linear within the range of 25% to 100% of its rated burden?

 

[RRaghunath]

IEC 61869-3 for Voltage transformers categorises VTs in to Cat. A & B. Cat. A is with burden ratings not exceeding 10VA. Others are Cat. B.
The accuracy class declared shall be valid from 0-100% burden in case of Cat. A VTs and from 25% - 100% burden for those in Cat. B.

 

[scottf]

Yes

 

[dfdt]

Thanks Scottf i too believe that the errors would be fairly linear as long as power factor is similar

 

[KSS227]

The standard insists for the linear characteristics between the said range. However, you may check the factory test reports of the actual VT of the manufacturer where you bought.