User manual
6 Technical data
97
Fig. 43. Additional uncertainty due to the phase error, depending on the phase angle.
Example
Calculation of measurement uncertainty of active power fundamental
component.
Conditions:
= 60
, U
RMS
U
nom
, I
RMS
= 5% I
nom
.
Basic uncertainty is
.
For the frequency range of 40..70 Hz, phase error of the analyzer is less
than 0.5
. After substituting equation:
therefore, the measurement uncertainty is:
In the same conditions, but with phase shift = 10
= 10
:
and the measurement uncertainty is:
These calculations do not take into account the additional errors intro-
duced clamps and transformers.