Rapid voltage change

A rapid voltage change or RVC is one of the power-quality (PQ) issue related to voltage disturbance. "According to IEC 61000-4-30, Ed. 3 standard, RVC is defined as "a quick transition in root means square (r.m.s.) voltage occurring between two steady-state conditions, and during which the r.m.s. voltage does not exceed the dip/swell thresholds." 
The main known effect of rapid voltage changes is light flicker, but other non-flicker effects also have been reported. 
Rapid voltage change effect.
The RVC voltage disturbance level is not as big as sag / dip and swell. While RVC events generally are not destructive for electronic equipment,it can be annoying for final users as they may influence light flicker. 