ABB Relion 670 series, Technical Reference Manual, Page: 469 / 1232

If a phase current is larger than the set operating current the signal from the comparator
for this phase is activated. This signal will, in combination with the release signal from
line disconnection (RELEASE input), activate the timer for the TRIP signal. If the fault
current remains during the timer delay
t , the TRIP output signal is activated. The
function can be blocked by activation of the BLOCK input.
BLOCK
TRIP
STUB PROTECTION FUNCTION
PU_A
PU_B
PU_C
OR
AND
ENABLE
en05000731_ansi.vsd
ANSI05000731 V1 EN
Figure 232: Simplified logic diagram for Stub protection (50STB)
7.9.3 Function block
ANSI05000678-2-en.vsd
STBPTOC (50STB)
I3P*
BLOCK
BLKTR
ENABLE TRIP
PICKUP
ANSI05000678 V2 EN
Figure 233: STBPTOC (50STB) function block
1MRK505222-UUS C
Section 7
Current protection
463
Technical reference manual