Voltage transformer
A voltage transformer (VT) is a transformer used in power systems to step-down extra high
voltage and provide low voltage either for measurement or to operate a protective relay.
1. Inductive Voltage Transformer (IVT)
2. Capacitor Voltage Transformer (CVT)
Accuracy Class Designation
Measuring Voltage Transformers
The accuracy class is designated by the highest permissible percentage voltage error at
rated voltage and with rated burden, prescribed for the accuracy class concerned.
Standard accuracy classes: 0,1 – 0,2 – 0,5 – 1,0 – 3,0 43
Protective Voltage Transformers
The accuracy class for a protective voltage transformer is designated by the highest
permissible percentage voltage error prescribed for the accuracy class concerned, from 5 %
of rated voltage to a voltage corresponding to the rated voltage factor. This expression is
followed by the letter P.
Standard accuracy classes 3P and 6P