Recording with a short averaging time may be sufficient to evaluate the performance of the mains and disturbances in it. However, equally detailed information can probably also be obtained with longer sample rates with activated recording of minimum and maximum values and event detection. An important advantage in this situation is that the volume of recorded data is much smaller which means faster data retrieval and analysis.
When conducting power quality surveys, the analysis is normally carried out over a longer period of time (usually 7 days), and therefore the averaging time needs to also be longer, typically set at 10 minutes.
Please note that there is no single best setting for both the averaging time and other parameters or event thresholds. Each mains system is different and so are the goals of the mains tests. Therefore, the optimal configuration of the analyser may require several approaches and will also depend on the experience.