A system and a method is provided for the detection and capture, and in particular for an ultra high speed detection and capture, of transients in input voltages by an intelligent electronic device. The system and method detects transients for input voltages in either phase to phase or phase to neutral measurements and permits a user to set threshold levels for detecting transients in input voltages. In an embodiment, the system and method further provides a field programmable gate array as a controller for managing transient detection. The field programmable gate array includes a state machine for determining the state of the sampled signal with respect to a threshold level at a specified waveform sample period.