Voltage Crest Factor; Crest Factor Current; K-Factor - Siemens 9410 Series User Manual

Power quality

Voltage crest factor

Crest factor current

K-factor

7EN05-0336-03
1. Navigate to Power Quality > Harmonics. The total harmonic distortion (THD)
screens are displayed.
2. Press the more button, and select the desired harmonics. The per-phase
harmonics are graphically displayed.
3. Press the left and right buttons to move to individual harmonics. The harmonic
number, magnitude and angle are displayed.
Related Topics
• Data viewing using your meter's display
Crest factor is the ratio of peak to RMS voltage values.
For a pure sinusoidal waveform, crest factor is equal to 1.414. The meter uses the
following equation to calculate crest factor:
V
peak
C =
V
RMS
Crest factor is the ratio of peak to RMS current values.
For a pure sinusoidal waveform, crest factor is equal to 1.414. The meter uses the
following equation to calculate crest factor:
I
p e a k
Cre s t fa ctor = ------------ -
I
R MS
K-factor relates the heating effect of a distorted current in a transformer to a sinusoidal
current with the same RMS magnitude — it describes a transformer's ability to serve
non-linear loads without exceeding rated temperature rise limits.
The K-factor is equal to the sum of the squares of the harmonic currents multiplied by
the squares of the harmonic order. The meter uses the following equation to calculate
K-factor:
h
2 2
(Ih x h )
n = 1
K =
h
2
Ih
n = 1
Where K is the K-factor, h is the harmonic order and Ih is the true RMS current of
harmonic order h.
C = Crest factor
V = Voltage peak
peak
V = Voltage RMS
RMS
C = Crest factor
I = Current peak
peak
I = Current RMS
RMS
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