Oscillatory transients are caused by switching operations, nearby lightning strikes, or other impulsive noise exciting electrical resonances present on the network. The most common in the distribution system is defined by IEEE 1159 as low frequency (under 5 kHz) and is often caused by capacitor bank switching.

The peak magnitude of the voltage can rise to up to twice the normal value. Despite the high peak voltage, capturing a short-lived transient can be difficult with traditional RMS-based waveform capture triggering. Waveshape triggering is much more suited to capturing these transients; this methodology is presented here.