ABB REL 505-C1 2.3 Series - Checking the Operation of the Du;Dt, DI;Dt Based Function

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Fuse failure supervision (FUSE) Chapter 10
Verifying settings by secondary
injection
8.4 Checking the operation of the du/dt, di/dt based function
Check the operation of the du/dt, di/dt based function, if included in the terminal.
Procedure
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. Connect the nominal dc voltage to the FUSE-CBCLOSED bi-
nary input.
3. Change the voltages and currents in all three phases simul-
tanously.
The voltage change should be greater then set DU> and the current
change should be less than the set DI<.
• The FUSE-VTSU and FUSE-VTSZ signals appear without any
time delay. If the remaining voltage levels are higher than the set
U< of the DLD function, only a pulse is achieved.
• FUSE-VTF3PH should appear after 5 seconds, if the remaining
voltage levels are lower than the set U< of the DLD function.
4. Apply normal conditions as in step 1.
The FUSE-VTSU, FUSE-VTSZ and FUSE-VTF3PH signals
should reset, if activated. See step 3.
5. Change the voltages and currents in all three phases simul-
tanously.
The voltage change should be greater then set DU> and the current
change should be greater then the set DI<.
The FUSE-VTSU, FUSE-VTSZ and FUSE-VTF3PH signals
should not appear.
6. Disconnect the dc voltage to the FUSE-CBCLOSED binary in-
put.
7. Apply normal conditions as in step 1.
8. Repeat step 3.
9. Connect the nominal voltages in all three phases and feed a
current below the operate level in all three phases.