Potential transformer or voltage transformer gets used in electrical power system for stepping down the system voltage to a safe value which can be fed to low ratings meters and relays. Commercially available relays and meters used for protection and metering, are designed for low voltage. This is a simplest form of potential transformer definition.
A voltage transformer theory or potential transformer theory is just like a theory of general purpose step down transformer. Primary of this transformer is connected across the phase and ground. Just like the transformer used for stepping down purpose, potential transformer i.e. PT has lower turns winding at its secondary.
The system voltage is applied across the terminals of primary winding of that transformer, and then proportionate secondary voltage appears across the secondary terminals of the PT.
This model of instrument voltage transformer includes two versions: JDZW-20 and JDZXW-20G. The units are cast in epoxy resin and fully enclosed. The units are suitable for electric systems of rated frequency of 50/60Hz and rated voltage of 24kV and below. They are used in indoor or outdoor service conditions. The products are designed in accordance with Standards IEC60044-2, IEC61869-3 and ANSI/IEEE C57.13.
New magnetic material using
protection or measurement windings
Measurement accuracy is 0.2s higher.
Phase shift is stability
Designed life is 30years long
Rated Voltage Ratio(KV)
Accuracy class and Accuracy class combination rated secondary output (VA)