Voltage Transformer - 2

Inductive Voltage Transformer(IEC 61869-3)

The standard values of rated output at a power factor of 0.8 lagging are:

10, 25, 50, 100VA

Accuracy Class - Measuring Voltage transformer:

The standard accuracy classes for single-phase inductive measuring voltage transformers are

0.1 – 0.2 – 0.5 – 1.0 – 3.0

The voltage error and phase displacement at rated frequency shall not exceed the values given in Table below at any voltage between 80% and 120% of rated voltage and??????with burdens between 25% and 100% of rated burden at a power factor of 0.8 lagging for rated burden.

Accuracy Class - Protective Voltage transformer:

The standard accuracy classes for a protective voltage transformers are 3P & 6P, and the same limits of voltage error and phase displacement will normally apply at both 5% of rated voltage and at the voltage corresponding to the rated voltage factor.

At 5% of rated voltage and at rated voltage multiplied by the rated voltage factor (1.5 or 1.9) with burdens between 25% and 100% of rated burden at a power factor of 0.8 lagging. At 2% of rated voltage, the limits of voltage error and phase displacement will be twice as high. The voltage error and phase displacement at rated frequency shall not exceed the values in table below.

Accuracy Class - Residual Voltage windings:

The accuracy class for a residual voltage winding shall be 6P or better.

Reference: CBIP Manual on Power system protection