Difference between RMS fluctuation and voltage fluctuation [Power Quality Analyzers]
The signals are calculated as RMS values every 200ms for both voltage and current (10 cycles on 50Hz and 12 cycles on 60Hz).
It is difficult to find instantaneous voltage drops that take place in half or 1 cycle, because it is averaged in a longer calculation period. Most equipment is not affected by voltage drops with a duration of a half or 1 cycle. Rather, It is used to watch fluctuation trends during longer periods or a few cycles.
The voltage RMs value is calculated in every cycle, so you can see an instantaneous voltage drop that happens in half a cycle or 1 cycle. This is useul for finding the instantaneous votlage fluctuation.