The IFD is an embedded mechanical sensor that activates when a sudden pressure from an internal arcing fault occurs inside the transformer.
The IFD also includes a standard pressure relief device (PRD) that is integrated into the sensor to save costs and space on the transformer tank.
During an internal fault, the rate at which the pressure rises is at least one thousand times faster than any other pressure rise that might occur. as a result of normal operating or external causes. This rapid pressure rise then becomes a reliable means to detect internal transformer faults.
When the internal fault occurs, the IFD releases a highly visible orange signal that crews can see from 60 feet (20 meters) away from the pole, even at night. The signal alerts crews that the transformer should not be re-energized, preventing a potential catastrophic failure and enhancing their safety.
The IFD reacts to a rapid pressure change of at least 0.5 psi over 5-7 milliseconds. The rapid pressure occurs only when the transformer has experienced an internal fault or short-circuit.
IFD Corp. Booth 3748