Subsynchronous oscillation monitoring

Subsynchronous oscillations occur below the fundamental frequency of a power system. These oscillations typically range from 0–50 Hz and can indicate potential issues which can lead to mechanical resonance or instability in equipment.

Your meter can help detect subsynchronous oscillations.

Overview

Use subsynchronous oscillation monitoring to continuously analyze a numerical input signal (such as power or current).

Your meter monitors subsynchronous oscillations by:

1. Converting the most recent 10 seconds of time-domain data into the frequency-domain.

2. Identifying the top ten frequency components with the highest magnitudes within the 0–50 Hz range.

   Note:  

   The meter ignores peaks below the greater of these two thresholds:

   1. A magnitude less than 0.1.

      OR

   2. A magnitude less than 0.1% of the sliding window’s average magnitude.

3. Calculating the RMS magnitudes for up to 50 configurable frequency groups.

4. Repeating the transformation and calculations approximately every second.

For more information about the Subsynchronous Oscillation Module, see ION Reference Help.