1. How do each of the four aggregation methods work in the Harmonics Measurement module?
- Tvs Aggregation
- Allows for arbitrary time intervals of RMS aggregation of the 150/180 values. For example, If you needed distortion values at 1-minute intervals, you would pulse the Evaluate input every minute and get the RMS of all the 150/180 intervals in each minute.
- Tvs Maximums
- Allows for arbitrary time intervals of maximum reporting of the 150/180 values. For example, If you needed max 150/180 distortion values over each 10 minutes, you would pulse the Evaluate input every 10 minutes and get the peak of all the 150/180 intervals in each 10 minutes.
- 4-30 150/180 Cycle
- The is the strict Class A aggregation specified in IEC61000-4-30. It is always comprised of the rms of fifteen 10/12Cycle basic intervals.
- 4-30 10 Minute
- The is the strict Class A aggregation specified in IEC61000-4-30. It is always comprised of the rms of every (typically 3000 of them) 10/12Cycle basic intervals in a 10minute interval.
2. What does Tvs stand for?
Tvs stands for "time very-short". It is a legacy term for 150/180 cycle (3s) interval predating IEC61000-4-30.
3. Is the 4-30 standards aggregation method an 'average'?
The 4-30 time aggregation of magnitudes is always an RMS (root-mean-square). For a constant signal, the result is the same as average. I believe RMS was chosen because it is proportional to thermal effects from fluctuating harmonics (where an average would under register the severity)
3. Which setting will give a 150/180 rolling average?
The "4-30 150/180 Cycle" method provides a non-overlapping rms approximately every 3 seconds.
4. Which setting will give a 10 minute rolling average?
The "4-30 10minute" method provides a non-overlapping rms every 10 minutes.
