In only the alternating current (AC) system, the transformer is based on the principle of changing the voltages at a constant frequency.
However, in the direct current (DC) system, there is no principle for the transformer that exists in the same way as in the AC system.
This is a phenomenon that can only be accomplished in an alternating current (AC) system, which is why the instrument transformer is not utilized in a direct current (DC) system so that it can scale down the value of the voltage or current.
Current (or) voltage in the HVDC can also be measured with the use of a few additional techniques.
DC & Transformer
Direct current (DC) passes in one direction & does not fluctuate over time.
When direct current is given to a transformer’s primary coil, it generates a steady magnetic field around it.
This steady magnetic field will not produce any induced voltage in secondary coil.
As a result, a transformer cannot use direct current to transport electrical energy from primary to secondary coil because it lacks a constantly changing magnetic field.
Significance of AC in Transformer
For a transformer to function properly, the magnetic field generated by primary coil should be constantly changing.
This can be accomplished by utilizing an alternating current (AC) in primary coil. AC produces a dynamic magnetic field when the current changes direction on a regular basis.
The continual shift in the magnetic field causes an alternating voltage in secondary coil.
Why doesn’t a transformer function with direct current?
Transformers do not work with direct current (DC) because they use the principle of electromagnetic induction, which requires a continually changing magnetic field to induce a voltage in secondary coil.
Direct current generates a continuous magnetic field that is insufficient to create a voltage in secondary coil.
Transformers function well with alternating current (AC) as it provides the continually changing magnetic field required for the electromagnetic induction operation.