Measurement In Ungrounded 3-Phase Networks With Neutral Conductor; Voltage Measurement On 3 Line Conductors - WAGO 750-495/040-00 Series Manual

WAGO-I/O-SYSTEM 750 XTR
750-495/040-00x 3-Phase Power Measurement Module 690 V
7.6.1.6 Measurement in Ungrounded 3-Phase Networks with Neutral
Conductor
For measurement in ungrounded 3-phase networks with a neutral conductor, the
I/O module offers 3 connection options:

• Voltage measurement on 3 line conductors

• Voltage measurement on 2 line conductors
• 3-Wattmeter Method (Artificial Star Point – ASP)
7.6.1.6.1 Voltage Measurement on 3 Line Conductors
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 ungrounded 3-phase networks with a
neutral conductor.
Voltage measurement is performed via voltage transformers (VTs). Voltages u
u and u
L2 L3
internally from the measurement results.
The current measurement is performed via current transformers (CTs) or
Rogowski Coils.
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 basic insulation and ground the
module-side N connection
In ungrounded 3-phase networks with a neutral conductor, always use voltage
transformers with at least basic 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 = 200 V
LN
Voltage" setting
- u = 400 V
LN
Voltage" setting
Parameter 47 is used for the setting.
are measured. The I/O module calculates voltages U
if a voltage ≤ 120 V
RMS
if a voltage > 120 V
RMS
Connect Devices 117
is parameterized for the "Secondary
RMS
is parameterized for the "Secondary
RMS
,
L1
, U and U
L1 L2 L3
Manual
Version 1.2.0