Measurement In Ungrounded Y/Δ Networks; 3-Wattmeter Method (Artificial Star Point - Asp) - WAGO 750-495/040-00 Series Manual

WAGO-I/O-SYSTEM 750 XTR
750-495/040-00x 3-Phase Power Measurement Module 690 V
7.7.2.3 Measurement in Ungrounded Y/Δ Networks
For measurement in ungrounded 3-phase networks, the I/O module offers
2 connection options:
- 3-wattmeter method (Artificial Star Point – ASP)
- 2-wattmeter method (Aron circuit/Blondel's Theorem)
7.7.2.3.1 3-Wattmeter Method (Artificial Star Point – ASP)
For voltage measurement, set the topology to "Artificial Star Point" ("ASP") in
WAGO-I/O-Check.
This topology is available with 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 without a
neutral conductor, with loads in a wye or delta connection, and with
U = U = U
12 23
The measurement circuit uses the principle of the 3-wattmeter method.
The N connection is not used. Voltage measurement is performed directly.
Voltages U
The current measurement is performed via current transformers (CTs) or
Rogowski Coils.
The measurement accuracy depends directly on the symmetry of the connected
voltages. Observe the details in the section "Measurement Errors" on the
conditions that need to be met.
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 = 200 V
LN
Voltage" setting
- u = 400 V
LN
Voltage" setting
Parameter 47 is used for the setting.
Observe the notes in the section "Function Description" > "Measurement
Errors" > "3-Wattmeter Method (Artificial Star Point – ASP)."
Insulation monitoring may be triggered
In ungrounded networks with insulation monitoring, the capacitive coupling of the
I/O module to FE can trigger the insulation monitoring, especially if multiple I/O
modules are connected in one network.
≤ 600 V .
31 RMS
*, U * and U * are measured to the artificial star point.
L1 L2 L3
if a voltage ≤ 120 V
RMS
if a voltage > 120 V
RMS
Connect Devices 173
is parameterized for the "Secondary
RMS
is parameterized for the "Secondary
RMS
Manual
Version 1.2.0