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Analysis of Harmonic Phase Angles
For the voltage and current harmonics, the following values are given additionally:
•
Prevailing phase angle (Prev°)
•
Prevailing ratio (PR)
The Prevailing phase angle represents harmonic emissions for intervals (such as the 10-min aggregation
interval). Prev° indicates the phase angle of a certain load. The prevailing phase angle is calculated via the
aggregation time from the phase angles of the 10-cycle or 12-cycle intervals. In the figures in the following
table, the prevailing phase angle is displayed as a red line.
The Prevailing ratio indicates load fluctuations during aggregation and indicates the degree of the variation
of a phase angle. For a prevailing-ratio value of 1, the phase angle of the corresponding harmonic is constant
(PR = 1: no fluctuation). The phase angles of the large variation (see following table), which have a prevailing
ratio of < 0.8, are high dispersal and the prevailing phasor has no useful meaning.
3 examples for the relation between prevailing ratio and prevailing phase angle:
[dw_phase-variation, 1, en_US]
Figure 3-5
However, the prevailing phasor only makes sense if the harmonic phase angles have a low variation (the
measurements are not highly dispersed in the complex plane). The prevailing ratio is proposed to indicate how
much the harmonic measurements vary in the complex plane.
NOTE
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You can find further information about this feature in the application notes
global/en/products/energy/energy-automation-and-smart-grid/power-quality-measurement.html
loads → SICAM Q200/SICAM Q100 → Other Sales Information → Application Notes → document: Applica-
tion Note Harmonic Phase Angles Direction.
Total Demand Distortion (TDD)
TDD in the device is the ratio of the harmonic currents to the maximum of the load current in the last meas-
uring interval.
[fo_tdd, 2, en_US]
NOTE
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For the calculations in the device, the value H = 50 is used.
I
is the maximum current of the last aggregation interval.
max
SICAM, SICAM Q100 7KG95xx, Manual
E50417-H1040-C522-A9, Edition 06.2021
Examples for Phase-Angle Variations
Measuring and Recording
3.2 Measurement and Evaluation Functions
https://new.siemens.com/
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