Voltage transformers (VT), additionally known as potential transformer (PT), ar a parallel connected variety of instrument electrical device. they’re designed to gift negligible load to the provision being measured associate degreed have an correct voltage quantitative relation and part relationship to modify correct secondary connected metering.
Potential electrical device or voltage electrical device gets employed in wattage system for stepping down the system voltage to a secure worth which might be fed to low ratings meters and relays. Commercially out there relays and meters used for cover and metering, ar designed for low voltage. this is often a simplest style of potential electrical device definition.
A voltage electrical device theory or potential electrical device theory is simply sort of a theory of general purpose step down electrical device. Primary of this electrical device is connected across the section and ground. a bit like the electrical device used for stepping down purpose, potential electrical device i.e. Pt has lower turns winding at its secondary.
The system voltage is applied across the terminals of primary coil of
that electrical device, and so proportionate secondary voltage seems across the secondary terminals of the atomic number 78. the secondary voltage of the atomic number 78 is mostly one hundred ten V. In a perfect potential electrical device or voltage electrical device, once rated burden gets connected across the secondary; the magnitude relation of primary and secondary voltages of electrical device is up to the turn’s magnitude relation and moreover, the 2 terminal voltages ar in precise part opposite to every different. however in actual electrical device, there should be a mistake within the voltage magnitude relation still as within the point in time between primary and secondary voltages. The errors in potential electrical device or voltage electrical device will be best explained by phasor diagram, and this is often the most a part of potential electrical device theory.
The voltage applied to initial} of the potential electrical device first drops because of the interior resistance of the first. Then it seems across the first winding and so remodeled proportionately to its turns quantitative relation, to the secondary. This remodeled voltage across the secondary can once more drop because of the interior resistance of the secondary, before showing across burden terminals. this is often the explanation of errors in potential electrical device.