ABB MDAR Instruction Manual page 48

I.L. 40-385.5
and Ios settings must be coordinated with one
another.
Besides the above supervisions, the MDAR (REL-
300) is supervised by a different kind of faulted phase
selector signal on each trip path. The faulted phase
selector uses current only
(I + I ) approach. For ØØ - unit tripping there must
1 2
be I present.
2
9.4 ZONE-1 TRIP
When the MDAR (REL-300) functional display
"STYP" is selected to "3ZNP" it will perform 3-zone
non-pilot functions.
For Zone-1 phase faults, the Z1P unit will see the
fault and operate. As shown in Figure 15. Outputs of
Z1P, IM plus the operation of FDOP, if applied, satis-
fies AND-2 and provides a high speed trip (HST) sig-
nal from OR-2 to operate the trip output telephone
relay. The trip circuit is monitored by a seal-in reed
relay S, which is in series with each trip contact in the
tripping circuits. The S relay will pick up if the trip cur-
rent is higher than 0.5 amp. The operation of the
seal-in contact "S" (i.e. after breaker trip coil has
been energized) provides the trip seal-in signal
TRSL. It feeds back to OR-4 and AND-8 to hold the
trip relay in operation until the breaker trips and the
52b contact opens (not shown in Figure 15). The trip
contact and the TRSL signal can be delayed dropout
by 50ms after the trip current is removed, providing
JMP4 on the microprocessor board is connected.
The TRSL signal from AND-8 plus the output signal
from AND-2 turn on the Zone-1 phase trip indicator
Z1P. The breaker trip and Zone-1 phase trip indica-
tors are sealed-in. They can be reset only after man-
ually pushing the RESET pushbutton on the front
panel, or through remote communication. The flash-
ing LED will be reset, but the fault information will still
remain in memory.
ø
The Z1P 3 trip logic AND-131 is also supervised by
the selectable OSB logic when the OSB1 is selected
to "YES".
Z1P logic AND-2 is also supervised by the FDOP
(forward directional overcurrent phase unit) when the
OSB1 or OSB2 or OSBP is selected to "YES" for
more security on some special power system appli-
cations (Refer to Chapter XI, paragraph G for a more
detailed explanation).
Similar operations function for Zone-1 single-phase-
to-ground faults. The Z1G unit sees the fault and
9-2
operates along with the I
ing AND-3. Tripping is initiated via OR-2 with Zone-1
ground trip Z1G indication. Logic AND-3 is also
supervised by the signal of RDOG (reverse direc-
tional overcurrent ground) for security.
A two-out-of-three "leading phase blocking" logic is
included for solving the overreach problem of the sin-
gle-phase ground distance units which may respond
to a ØØG fault.
The Z1G unit is also supervised by the signal of
unequal-pole- closing.
The T1 timer, as shown in Figure 15, provides time
delay on Z1P/Z1G trip if required. The range of T1
timer is 0 to 15 cycles in 1.0 cycle steps. Normally,
the T1 timer should be selected to zero time delay,
unless it is needed. For example, when using MDAR
(REL-300) as a non-pilot 3PT backup with another
system operated on SPT mode, set MDAR (REL-
300) Zone-1 with delay.
HST signal also is connected to the reclosing initia-
tion logic.
Either or both Zone-1 phase and Zone-1 ground
function(s) can be disabled by selecting the Z1P and/
or Z1G to OUT.
9.5 ZONE-2 TRIP
For Zone-2 phase faults, the Z2P unit will see the
faults, plus the output of IM, operates the Zone-2
phase timer T2P. Z2P output plus the T2P timer out-
put satisfy AND-4 as shown in Figure 16. AND-4 out-
put provides time delay trip signal TDT via OR-3.
Signal TDT picks up OR-4 (Figure 15) and operates
the trip relay. The tripping and targeting are similar as
described in Zone-1 trip except with Zone-2 phase
time delay trip Z2P indication.
Similar operation occurs for Zone-2 single-phase-to-
ground faults. The Z2G unit sees the fault and oper-
ates. This plus the operation of the I
T2G, satisfies AND-5, and provides the TDT signal
via OR-3 with Zone-2 ground time delay trip indicator
Z2G.
ø
Zone-2 3 unit is supervised by the selectable
OSB2.
The single phase ground distance units may respond
to a ØØG fault. The output of the Z2G unit plus the
operation of the ØØ - selection will trip the Z2P via
OR-157, T2P and AND-18. Leading phase blocking
is unnecessary for an overreach zone device.
and FDOG units, satisfy-
OM
, FDOG and
OM