Detail relating to IEC61000-4-30 ION modules

[richard_schwass]

Hi there,

We are beginning to work with a customer to develop frameworks around the early warning diagnosis of feeder faults. This will center around monitoring of high-speed rolling voltages, currents and harmonics.

It is clear to me that the 4-30 parameters which update 150/180 cycles could be best to use. Therefore theHarmonics Measurement and Power Quality Aggregator modules will get us started.

1. How do each of the four aggregation methods work in the Harmonics Measurement module?

• Tvs Aggregation
• Tvs Maximums
• 4-30 150/180 Cycle
• 4-30 10 Minute

2. What does Tvs stand for?

3. Is the 4-30 standards aggregation method an 'average'?

3. Which setting will give a 150/180 rolling average?

4. Which setting will give a 10 minute rolling average?

Kind regards

Richard

[DanL]

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.

[richard_schwass]

Thanks Dan,

Perfect answers!

We should get this detail added to the ION Reference manual...

Eric Tjiptadjaja​, Arneil Dalope​, Leah Sun​

Cheers Richard

[GrahamSpencer]

Hi Richard, I assume your application is for feeder cables where you could have insulation failure that develops over some time, allowing possible detection by monitoring the parameters for small changes?

thanks

Graham