4 Measured Quantities and Recording
4.1 Power Quality Measuring System and Recording System
34
SICAM Q100, 7KG95xx, Device Manual
E50417-H1040-C522-A4, Edition 03.2018
4.1.6
Harmonic Power and Harmonic Angles
Measurement of phase angles is helpful to analyze different phenomena. The measurement can be used for
the following purposes:
•
Evaluation of harmonic flows throughout the system
•
Identification of harmonic sources and harmonic sinks
•
Calculation of active, reactive, and apparent powers of harmonics
•
Assessment of harmonic-current measurements in different points in the system
•
Modeling of disturbing loads and evaluation of their disturbing effect
•
Design countermeasures for disturbing loads
Therefore the SICAM Q100 provides these new measurements to support new evaluation alternatives that
support the customer in minimizing the influence of harmonics in the network or load, as defining mitigation
devices, filters, reactive compensation, etc.
Harmonic Directions
SICAM Q100 measures harmonics of currents, voltages, and powers up to the 63rd order. Measuring is done
according to the standard IEC 61000-4-7.
The following values are given for each harmonic:
•
RMS value (for power: RMS value and sign)
•
Phase angle
The sign of the active power of the single harmonic indicates the direction of power flow of this harmonic in a
system from the device installation point of view. Thus, it is possible to indicate loads that generate the
harmonics and that are probably the cause of the harmonics.
For voltage and current, the given
phase angle
of the harmonic refers to the voltage of the fundamental
component in respective phase. The phase angle between the current harmonic and the corresponding voltage
harmonic is used to calculate the sign of active harmonic power.
Figure 4-4
Principle of the Harmonic Directions
For measuring the RMS values and the phase angles, a 10-cycle interval is used for 50-Hz distribution systems.
For 60-Hz distribution systems, a 12-cycle interval is used.
Supply system
Load
Measuring system
P
(n)
= U
(n)
x
I
(n)
x
cos(
u(n)
-
i(n)
)
P
(n)
0
P
(n)
< 0