Sag And Swell - Allen-Bradley Powermonitor 3000 User Manual

Sag and Swell

Allen-Bradley HMIs
• Table A.36 Harmonic Results; Odd Harmonics 23 to 41 (M6 and
M8)
• Table A.37 Harmonic Results; Even Harmonics 2 to 20 (M6 and
M8)
• Table A.38 Harmonic Results; Even Harmonics 22 to 40 (M6 and
M8)
• Table A.48 Harmonic Results; Odd Harmonics 43 to 63 (M8
only)
• Table A.49 Harmonic Results; Even Harmonics 42 to 62 (M8
only)
Each of these tables consists of 14 floating-point elements containing
the following parameters:
• Channel: 1 = V1, 2 = I1, 3 = V2, 4 = I2, 5 = V3, 6 = I3, 7 = I4 (no
averages)
• Type of harmonic data: 0 = per cent harmonic distortion, 1 =
magnitude
• Nth harmonic: expressed according to the type parameter.
Magnitude type is referenced to the primary side of PTs and CTs.
Range: 0.0 to 999.9 * 10
• FFT iteration: each new FFT calculation (used in the previous
four parameters) increments by one from 0 to 32,767 and rolls
back to 0
In Tables A.36, A.37 and A.38 the first nth harmonic element is
reserved and returns a value of 0.
The Powermonitor 3000 M6 and M8 models are is capable of
detecting voltage sags and swells. There are many definitions for sag
1
and swell. IEEE 1159
"A decrease to between 0.1 and 0.9 pu in rms voltage or current
at the power frequency for durations of 0.5 cycle to 1 minute".
1
IEEE 1159 defines swell as:
"An increase in rms voltage or current at the power frequency
for durations from 0.5 cycles to 1 minute. Typical values are
1.1-1.8 pu".
22
defines sag as:
Publication 1404-UM001D-EN-E - October 2004
Advanced Features 8-13