www.janitza.com UMG 103-CBM
29
7.4.3 Connection variants for voltage mea-
surement
Fig.: Voltage measurement in three-phase 4-conductor
system
Fig.: Voltage measurement in a single-phase 3-conductor
system
Load
Load
7.4.1 Overvoltage
The voltage measurement inputs are designed for
measurements in low-voltage networks in which
nominal voltages occur as described in the chap-
ter „Warning“ on page 11„13. Technical data“
on page 54.
Information on the rated surge voltages and
overvoltage categories can also be found in the
technical data.
7.4.2 Frequency
The device:
· Requires the mains frequency for the measure-
ment and calculation of measured values.
· Is suitable for measurement in networks in which
the fundamental oscillation of the voltage is in
the range from 45 Hz to 65 Hz.
The mains frequency is determined from the mea-
sured voltage of phase L1. The sampling frequen-
cy of the voltage and current measurement inputs
results from the mains frequency.
When measuring with strongly distorted volt-
ages, the frequency of the voltage fundamental
oscillation can no longer be determined exactly.
This means that for strongly distorted measured
voltages, the corresponding mains frequency
should have a fixed specification. Voltage distor-
tions occur, for example, during measurements
on consumers that are operated with phase-angle
control. Distortions of the current do not influence
the frequency determination.
INFORMATION
The device only allows the setting of one voltage
transformer ratio for all phases!
The voltage transformer ratios can be configured
conveniently via
· the GridVis
®
software.
For information on voltage transformer configu-
ration, see the chapter „9.1 Current and voltage
transformers“ on page 38.
Fig.: Voltage measurement in a three-phase 4-con-
ductor system via voltage transformer
Load
L
L
L
N
1 2 3
Voltage
L
L
L
N
1
2
3
Voltage
L
L
L
N
1 2 3
Voltage
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