ABB RELION RET670, Commissioning Manual, Page: 294 / 328

If the function LDC is set to Zero , this test is omitted.
2. Open the voltage control display on the LHMI in Main Menu/Control/
Commands/TransformerVoltageControl (ATCC, 90) .
IEC13000251-1-en.vsd
3. In this view, check the following settings:
3.1. Check that
Control Mode is set to Manual .
3.2. Operate the tap changer so that the Load Voltage corresponds to the Voltage
Set Point .
3.3. Check that neither the Raise or the Lower command are operating. Voltage
Deviation should be less than 100%.
3.4. Compare the values of Bus Voltage and Load Voltage .
UL can be obtained by a vector calculation where IL is the load current and
values for RL and XL are the settings given in primary system ohms.
~
L
o
a
d
R
L
X
L
V
B
V
L
V
B
R
L
I
L
jX
L
I
L
Re
ANSI06000487-2-en.vsd
For inductive load, the Bus Voltage should be higher than the Load Voltage . If not, current
circuits are incorrect and must be reversed. Incorrect current polarity may be an issue with
Section 12
1MRK 504 165-UUS -
Primary injection testing
288 Transformer protection RET670 2.2 ANSI
Commissioning manual