Completing The Test - ABB RET670 Commissioning Manual

1MRK 504 165-UEN A
11.4.17.2
Transformer protection RET670 2.2 IEC
Commissioning manual
Testing functionality by secondary injection
protection when performing the secondary injection tests. Measure operating
characteristics during constant current conditions. Keep the injected current as
close as possible to the rated value of its associated input transformer or lower.
Ensure, however, that it is higher than 30% of the rated current. Ensure that the
maximum continuous current of an IED does not exceed four times Its rated value,
if the measurement of the operating characteristics runs under constant voltage
conditions.
Measuring the operate limit of set values of load encroachment function
The load encroachment does not have any special output to be verified. It can only
be verified with the distance START and TRIP outputs.
Steps to test the load encroachment:
1. Supply the IED with healthy conditions for at least two seconds.
2. Apply the fault condition and slowly decrease the injected impedance to find
the operate value for of the phase-to-earth and phase-to-phase loops.
Under voltage seal-in
The under voltage seal-in logic can be verified using the TRUV and STUV outputs.
Steps to verify the logic:
1. Keep all the current and voltage in normal balanced condition.
2. Keeping the phase current at rated value, slowly reduce the voltage till it enters
into the respective zone mho characteristics and also below the set value of the
under voltage seal-in logic.
3. Before the operate time delay of the respective zone, reduce the current
magnitude so that the operating impedance moves out of the mho
characteristics.
4. The under voltage seal-in should give a START and TRIP after the operate
time delay is set for the under voltage logic.

Completing the test

Continue to test another function or end the testing by setting the parameter
TestMode to Off under Main menu/Tests/IED test mode/1: TESTMODE. If
another function is tested, then set the parameter Blocked to No under Main menu/
Tests/Function test modes/Impedance/ZGVPDIS/1: ZGVPDIS for the function,
or for each individual function in a chain, to be tested next. Remember to set the
parameter Blocked to Yes, for each individual function that has been tested.
Section 11
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