Zone-1 Trip; Zone-2 Trip - ABB REL 301 Instruction Leaflet

2.3.1 Zone-1 Trip (Figure 2-5)
For Zone-1 phase faults, the Z1P units will identify the fault and operate. The 3Ø fault logic is
supervised by the load restriction logic via AND131C at AND 131. Oversight of zone-1 3Ø trip
logic, via AND 131, includes supervision by the selectable out-of-step blocking (OSB) logic (see
Section 2.4.16) and directional supervised, by the Forward Directional Overcurrent Phase units
(FDOPA, FDOPB and FDOPC) for more security during close-in faults. OSB supervision is by
both the OSB logic and the subsequent OSB logic if the option is supplied and is enabled by
setting "OS Block" to "YES". Additional 3Ø fault logic supervision is by way of "fault detector"
overcurrent input (IM) and loss of potential supervision (LOPBS) at AND 2. Loss of potential su-
pervision is enabled by setting "LOP Blk" to either "Yes" or "All".
Z1P 3Ø output satisfies AND 2B, if "Zone1 Ø" is set to any value other than "Disabled", after
the zone-1 time delay T1 ("T1 Timer" if set) has expired and provides a high-speed trip (HST)
signal, via OR 2, to operate the trip output relay. The trip circuit is monitored by a seal-in reed
relay (S), which is in-series with each tripping contact circuit. The S relay will pick up if the trip
current is higher than 0.5 Amp. The operation of the S contact will turn-on the breaker trip indi-
cators (for fault records), and feeds back to OR 4 to hold the trip relay in operation until the power
circuit breaker (PCB) trips and the PCB's 52a contact opens (not shown in Figure 2-5). In the
event a longer duration trip output is required, trip contact dropout can be delayed an additional
50 milliseconds, after the trip current is removed, by inserting jumper JMP4 (JP4 on the Micro-
processor module). See Figure 5-3 for location. The trip seal (TRSL) signal plus the output sig-
nal from AND 2B turns on the Zone-1 phase trip indicator Zone1 Ø, for targeting plus ZONE-1
and MØ LEDs. The breaker trip and Zone-1 phase trip indicators information is stored and/or
sealed in. They can be reset by external R
However pushing the R
set the flashing LEDs, but the fault target information will remain in memory.
Similar operation occurs for Zone-1 single-phase-to-ground faults. The Z1G units (ØA, ØB and
ØC) detect faults and operate AND 132, AND 133 or AND134 which are supervised by overcur-
rent fault detector IOM and ground directional unit FDOG (forward directional overcurrent
ground). Zone-1 ground logic AND 3 is also supervised by the signals of 'NOT' RDOG (reverse
directional overcurrent ground) or 'NOT' UNEQUAL POLE CLOSING or' NOT' LOPBS. These
signals add security from incorrect operations for close-in reverse faults or operations resulting
from PCB pole misalignment errors or loss of potential, respectively. Z1G output satisfies AND
3B, if "Zone1 G" is set to any value other than "Disabled", after the zone-1 time delay T1 ("T1
Timer" if set) has expired and provides a high-speed trip (HST) signal, via OR 2, to operate the
trip relay. The trip seal (TRSL) signal plus the output signal from AND 3B turns on the Zone-1
ground trip indicator Zone-1 G, for targeting plus ZONE-1 and ØA , ØB or ØC LEDs. Zone-1
ground trip indicator information is stored and/or sealed in.
A two-out-of-three "leading phase blocking" logic is included to solve the overreach problem of
the single-phase
phase-to-phase-to-ground (ØØG) fault.
The high-speed trip (HST) signal also is connected to the reclosing initiation logic.
2.3.2 Zone-2 Trip (Figure2-6)
For Zone-2 phase faults, the appropriate Z2P unit will detect the fault and operate the Zone-2
phase timer. The timer, denoted T2P in Figure 2-6 can be selected to be either a definite time
delay or a torque controlled, inverse time overcurrent delay (CO type) characteristic*.
2. Bold italic type indicates an output e.g. LEDs or contact output
3. Bold type, with small capital letters, indicates an input e.g. RESET push-button or voltage input
ESET 3
push-button, will only return the display to "METER" mode and re-
ESET
ground distance units,
voltage or through remote communications.
when and if they
I.L. 40-386.4
2
respond to a
2-3