If a power quality analyser recorded all 200-millisecond RMS values, we would get 3.024 million measurements. Processing of such amount of data would be time consuming and difficult.
Therefore, the averaging can be used. This involves recording one value per a specified time interval for the analysis purposes. For the EN 50160 standard, such time interval is 10 minutes. In such case, the analyser calculates an average 10-minute value on the basis of about three thousand 200-millisecond values (approximately, because in reality the conventional 200-millisecond value is a 10/12-period value synchronized with the mains frequency). Each average voltage value is recorded every 10 minutes which gives “only” 1008 measurement results.