PM 1001484 000 06
Device handbook SINEAX DM5000
68/87
A2 Harmonic analysis
The harmonic analysis is performed according IEC 61000-4-7 over 10 cycles at 50Hz resp. 12 cycles at
60Hz. If a measured quantity is available depends on the selected system.
Measurement
p
res
en
t
m
ax
1L
2L
3L
b
3
L
b
.P
3L
u
3
L
u
.A
4L
b
4
L
u
.O
4L
u
THD Voltage U1N/U
● ● √ √ √
√ √ √
THD Voltage U2N
● ● √
√ √
THD Voltage U3N
● ●
√ √
THD Voltage U12
● ●
√ √ √
THD Voltage U23
● ●
√ √ √
THD Voltage U31
● ●
√ √ √
THD Current I1/I
● ● √ √ √ √ √ √ √ √ √
THD Current I2
● ● √
√ √ √ √
THD Current I3
● ●
√ √ √ √
TDD Current I1/I
● ● √ √ √ √ √ √ √ √ √
TDD Current I2
● ● √
√ √ √ √
TDD Current I3
● ●
√ √ √ √
Harmonic contents 2
nd
...50
th
U1N/U
● ● √ √ √
√ √ √
Harmonic contents are available
up to the 89
th
(50Hz) or 75
th
(60Hz) on the Modbus interface
Harmonic contents 2
nd
...50
th
U2N
● ● √
√ √
Harmonic contents 2
nd
...50
th
U3N
● ●
√ √
Harmonic contents 2
nd
...50
th
U12
● ●
√ √ √
Harmonic contents 2
nd
...50
th
U23
● ●
√ √ √
Harmonic contents 2
nd
...50
th
U31
● ●
√ √ √
Harmonic contents 2
nd
...50
th
I1/I
● ● √ √ √ √ √ √ √ √ √
Harmonic contents 2
nd
...50
th
I2
● ● √
√ √ √ √
Harmonic contents 2
nd
...50
th
I3
● ●
√ √ √ √
●
Available via communication interface only
Harmonics
Harmonics are multiples of the fundamental resp. system frequency. They arise if non-linear loads, such
as RPM regulated drives, rectifiers, thyristor controlled systems or fluorescent lamps are present in the
power system. Thus undesired side effects occur, such as additional thermal stress to operational
resources or electrical mains, which lead to an advanced aging or even damage. Also the reliability of
sensitive loads can be affected and unexplainable disturbances may occur. In industrial networks the
image of the harmonics gives good information about the kind of loads connected. See also:
Increase of reactive power due to harmonic currents
TDD (Total Demand Distortion)
The complete harmonic content of the currents is calculated additionally as Total Demand Distortion,
briefly TDD. This value is scaled to the rated current resp. rated power. Only this way it's possible to
estimate the influence of the current harmonics on the connected equipment correctly.
Maximum values
The maximum values of the harmonic analysis arise from the monitoring of THD and TDD. The maximum
values of individual harmonics are not monitored separately, but are stored if a maximum value of THD or
TDD is detected. The image of the maximum harmonics therefore always corresponds to the dedicated
THD resp. TDD.
The accuracy of the harmonic analysis strongly depends on the quality of the current and voltage
transformers possibly used. In the harmonics range transformers normally change both, the
amplitude and the phase of the signals to measure. It's valid: The higher the frequency of the
harmonic, the higher its damping resp. phase shift.
