WAGO-I/O-SYSTEM 750 XTR
Connect Devices 115
750-495/040-00x 3-Phase Power Measurement Module 690 V
Manual
Version 1.2.0
7.6.1.5 Measurement in Grounded Single-Phase Split-Phase Networks
The “4-Wire Wye” (“4-W”) topology is available in WAGO-I/O-
Check
for voltage
measurement.
This topology is fixed in firmware versions 04 and below and selectable in
WAGO-I/O-
Check
in firmware versions 05 and above.
The voltage transformer ratio can be parameterized in firmware versions 05 and
above and WAGO-I/O-
Check
versions IO-3.18.1 (CS0609) and above.
This measurement circuit is used in all grounded single-phase networks with an
additional center tap as a neutral conductor and with various types of load
connection.
Voltage measurement is performed directly. The voltages U
L1
and U
L2
are
measured. The I/O module calculates the voltage U
12
internally from the
measurement results.
The current measurement is performed via current transformers (CTs) or
Rogowski Coils.
The measured values of unconnected voltage and current measurement inputs
have no significance.
The current transformer ratio must be taken into account for the correct
calculation of all values in the process image.
The nominal input voltage is:
- U
LN
= 200 V
RMS
if a voltage ≤
120 V
RMS
is parameterized for the “Secondary
Voltage” setting
- U
LN
= 400 V
RMS
if a voltage > 120 V
RMS
is parameterized for the “Secondary
Voltage” setting
Parameter 47 is used for the setting.
To avoid erroneous measured values for the unused phase, the unused voltage
input L2 can be connected to the N connection. Depending on the connection
configuration of loads Z1, Z2 and Z3 (see the following connection schematic),
the sizes of the individual phases can be specified either for all individual loads
or, through external calculations, for just the total load.
- Load configuration: Z1 and Z2:
The measured quantities are valid as for the “4-Wire Wye” measurement
topology.
- Load configuration: Z3 individually:
Summing the 2 individual power/individual energy values yields the total
power/total energy (sum of L1 and L3).
- Load configuration: Z1, Z2 and Z3:
The total power and total energy can be calculated from the individual
power/individual energy values. Because of the concatenated currents of the
individual loads, the individual currents, individual phase angle, individual
powers and individual energies can no longer be distinguished.