ABB RET670 Commissioning Manual page 284

Section 12
Primary injection testing
278
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).
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.
~
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 physical wiring or the current direction convention selected for the
CT analogue input as part of the setting in the PST setting.
IEC13000251-1-en.vsd
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IEC06000487-2-en.vsd
Transformer protection RET670 2.2 IEC
1MRK 504 165-UEN A
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Commissioning manual