Direct measurement of voltage in High Voltage
System is not possible because of insulation
problem of measuring instruments. It is also not
possible to apply high voltage directly to
protective relays used for system protection due
to high insulation problem. Therefore voltage
transformers are used to step down high voltage
to a low value accurately in proportion to their
ratios.
Basic Functions of Potential Transformers are :-
To transform the line voltage with
reasonably good accuracy to a value
which is suitable for
standard measuring instruments relays
etc.
To isolate the measuring instruments,
meters, relays etc. from high voltage
side of an
electrical installation.
To sense abnormalities in voltage and
give voltage signals to protective
relays to isolate
Basic Functions of Potential Transformers are :-