A voltage transformer (PT) is similar to a transformer in that it is used to change the voltage on a line.But the purpose of transformer transform voltage is to transport electric energy, so the capacity is very large, generally with kilovolt-ampere or mva for the calculation unit;Purpose and voltage transformer voltage transformation is used to measuring instrument and supply power relay protection device used to measure the line voltage, power and energy, or used in the circuit failure protection circuit of expensive equipment, motor and transformer, voltage transformer capacity is small, therefore, generally only a few volt-ampere, dozens of volt-ampere, biggest and no more than one kva.

1, An overview of the

The primary and secondary complete voltage sensor is a capacitive ac sensor in line with the technical specifications of the primary and secondary complete equipment of the state grid. It can be matched with LW3, ZW20, ZW32 and FZW28 high-voltage switches on the column, with low power consumption and high accuracy.

2, The characteristics of

1) composite film capacitor similar to CVT structure is adopted, with good long-term stability and long-term operation experience of power grid.

2) the capacitance of the main capacitor is 530pF, which has the advantages of large working current and strong anti-interference ability.

3) small output internal resistance, can adapt to various cables, overcome the error caused by cables, cable interchange error is less than 0.15%.

4) has the characteristics of small precision affected by environmental temperature change, in - 40 ℃ ~ 70 ℃ temperature range error variation is less than 0.25%.