Abstract:
Sweep Frequency Response Analysis has
become very popular now – a - days due to its ability to
provid e comprehensive information regarding mechanical
as well as electrical condition of power transformers. The
SFRA is a comparative method and provides better
information when evaluation of Transformer condition is
done by comparing actual set of SFRA result s with
reference results. This field experience consists
400/220/33KV ICT bank, formed with three single phase
unit with capacity of 167MVA each. A heavy fault current
was fed by ICT due to failure of LA provided on delta
winding formed outside. Mechanical defects ostensibly
occur due to a short circuit current flowing through power
transformer in case of terminal faults i.e. fault near to
power transformer. To know the mechanical integrity of
power transformer SFRA test is carried out and is supported
by o ther tests i.e. DC resistance, Magnetic balance,
Winding resistance, capacitance and tan delta etc. The test
results reveals that SFRA is capable of providing more
information about mechanical deformation about power
transformers compared to other tests.
