148 Connect Devices
WAGO-I/O-SYSTEM 750 XTR
750-495/040-00x 3-Phase Power Measurement Module 690 V
Manual
Version 1.2.0
7.6.2.7 Measurement in Ungrounded Single-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.
The measurement circuit basically corresponds to the “Ungrounded 3-Phase
Network with Neutral Conductor for Power Measurement and Voltage
Measurement on 3 Line Conductors for U
LN
> 400 V
RMS
and u
LN
≤
400 V
RMS
”
connection schematic, except that only connections L1 and N and connections
I1+ and I1− are con
nected.
Voltage measurement is performed via voltage transformers (VTs).
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 voltage transformer ratio and current transformer ratio must be taken into
account for the correct calculation of all values in the process image.
Always use voltage transformers with reinforced insulation and ground the
module-side N connection
In ungrounded single-phase networks with a neutral conductor, always use
voltage transformers with reinforced insulation and ground the module-side N
connection.
Otherwise, touch-proof protection from the system may no longer be given in the
event of a fault. This can cause electric shock or burns.
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.