Answer: An suppression coil is also known as Peterson coil or ground fault neutralizer, is an iron core tapped reactor connected in neutral to ground connection. The reactor is provided with tapping so that it can be tuned to the system capacitance.
The function of suppression coil is to make the arcing ground fault self extinguishing and in case of sustained fault, to reduce ground fault current to a comparatively low value so that the system can be kept in operation with one line grounded.
he arc suppression coil (ASC), also known as Petersen coil, is used to compensate the capacitive earth fault currents supplied by outgoing feeders at a substation. The compensation can be either centralized or distributed. With the centralized design, one ASC unit will handle the compensation of all of the outgoing feeders.