Checking The Operation Of The Du/Dt And Di/Dt Based Function - ABB RET670 Commissioning Manual

1MRK 504 165-UEN A
11.9.2.5
Transformer protection RET670 2.2 IEC
Commissioning manual
Testing functionality by secondary injection
4. Apply three-phase currents with their rated value and zero voltages.
5. Decrease the measured current in one phase until the DLD1PH signal
appears.
6. This is the point at which the dead line condition is detected. Check the value
of the decreased current with the set value IDLD< (IDLD< is in percentage of
the base current IBase).

Checking the operation of the du/dt and di/dt based function

Check the operation of the du/dt and di/dt based function if included in the IED.
1. Simulate normal operating conditions with the three-phase currents in phase
with their corresponding phase voltages and with all of them equal to their
rated values.
2. Change the voltages and currents in all three phases simultaneously.
The voltage change must be higher than the set value DU> and the current
change must be lower than the set value DI<.
• The BLKU and BLKZ signals appear without any time delay. The
BLKZ signal will be activated only if the internal deadline detection is
not activated at the same time.
• 3PH should appear after 5 seconds, if the remaining voltage levels are
lower than the set UDLD< of the dead line detection function.
3. Apply normal conditions as in step 1.
The BLKU, BLKZ and 3PH signals should reset, if activated, see step
2.
4. Change the voltages and currents in all three phases simultaneously.
The voltage change must be higher than the set value DU> and the current
change must be higher than the set value DI<.
The BLKU, BLKZ and 3PH signals should not appear.
5. Repeat step 2.
6. Connect the nominal voltages in all three phases and feed a current below the
operate level in all three phases.
7. Keep the current constant. Disconnect the voltage in all three phases
simultaneously.
The BLKU, BLKZ and 3PH signals should not appear.
8. Change the magnitude of the voltage and current for phase 1 to a value higher
than the set value DU> and DI<.
9. Check that the start output signals STDUL1 and STDIL1 and the general start
signals STDU or STDI are activated.
10. Check that the start output signals for the current and voltage phases 2 and 3
are activated by changing the magnitude of the voltage and current for phases
2 and 3.
Section 11
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