Measurement Of U; Measurements In Y Networks With Star Points Grounded On The Source Side; Ll Rms; 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

Measurement of U

The following subsections describe all connection options of the I/O module in
networks without a neutral conductor for U
7.7.2.1 Measurements in Y Networks with Star Points Grounded on the
Source Side
For measurement in 3-phase networks without a neutral conductor, the
I/O module offers 2 connection options:
- 3-wattmeter method (Artificial Star Point – ASP)
- 2-wattmeter method (Aron circuit/Blondel's Theorem)
7.7.2.1.1 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 3-phase networks without a neutral
conductor with a star point grounded on the source side, and with loads in a wye
or delta connection, with voltages U
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:
= 200 V
- u
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)."
over 400 V
LL
*, 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
RMS
> 400 V .
LL RMS
= U = U ≤ 600 V
12 23 31
is parameterized for the "Secondary
RMS
is parameterized for the "Secondary
RMS
Connect Devices 167
.
RMS
Manual
Version 1.2.0