DEFINITION
(ANSI std. 1100-1992)
A subcycle disturbance in the AC
waveform that is evidenced by a sharp
brief discontinuity of the waveform.
Transients may be of either polarity
and may be of additive or subtractive energy to the nominal waveform.

Transients are also known as spikes
or surges and normally are on the line
for only 1/1000th of a second or less
(less than 1 millisecond). They can be
from a few to 10,000 volts-peak above or below the voltage sinewave or data line signal. Voltage transients normally last only about 50 microseconds and current transients last typically 20 microseconds according to the ANSI C62.41-1991 which is the standard for transients in facilities operating under 600 Volts RMS. Transients can either
be of the oscillatory or impulse types.