8.5
Fuse failure supervision (FUSE)
4.
Apply normal conditions as in step 1.
The FUSE-VTSU, FUSE-VTSZ and FUSE-VTF3PH signals should re-
set, if activated. See step 3.
5.
Change the voltages and currents in all three phases simultanously.
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 input.
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.
10. Keep the current constant. Disconnect the voltage in all three phas-
es simultaneously.
The FUSE-VTSU, FUSE-VTSZ and FUSE-VTF3PH signals should not
appear.
Completing the test
Continue to test another function or complete the test by setting the test mode to off.
Chapter 13
Verifying settings by secondary
injection
101