A device and a method for mitigating magnetic core saturation in a current
transformer. The Primary Winding of the current transformer is connected
to power system and protective relay system is connected to secondary winding
of the current transformer. The device comprises a current sensor connected
in series with secondary winding of current transformer and connected to
input of analog measurement circuit. The output of analog measurement circuit
is connected to control circuit. The output of control circuit is connected
normally closed switch connected across the secondary winding. A compensating
flux generating and injecting circuit is connected across the normally closed
switch and normally open switch is connected in series with compensating
flux generating and injecting circuit. The output of control circuit is further
connected to normally open switch. The output of compensating flux generating
and injecting circuit is connected to secondary winding of current transformer
through normally open switch and closed switch.
Indian patent application no. 592/MUM/2008 Patent grant no.
Inventors: S A Soman, P R Apte, and P V Chawande