Date Code 990215 Trip and Target Logic 5-1
SEL-351P Manual Técnico
SECTION 5: TRIP AND TARGET LOGIC
T
RIP
L
OGIC
The trip logic in Figure SECTION 5: .1 provides flexible tripping with SEL
OGIC
®
Control
Equation settings:
TRCOMM Communications-Assisted Trip Conditions.
Setting TRCOMM is supervised by communications-assisted trip logic.
See Communications-Assisted Trip Logic – General Overview later in
this section for more information on communications-assisted tripping.
DTT Direct Transfer Trip Conditions.
Note in
Figure SECTION 5: .1 that setting DTT is unsupervised. Any
element that asserts in setting DTT will cause Relay Word bits COMMT
and TRIP to assert to logical 1.
A typical setting for DTT is:
DTT = IN106
where input IN106 is connected to the output of direct transfer trip
communications equipment.
Setting DTT is also used for Direct Underreaching Transfer Trip (DUTT)
schemes.
To illuminate an LED to indicate a communications-assisted trip (via
SEL
OGIC
Control Equation settings TRCOMM or DTT), reprogram an
LED with Relay Word bit COMMT. The LED also has to be set as a trip-
latch LED (see Front-Panel Status and Trip Target LEDs subsection in
Section 1: Factory-Set Logic).
TRSOTF Switch-Onto-Fault Trip Conditions.
Setting TRSOTF is supervised by the switch-onto-fault condition SOTFE.
See Switch-Onto-Fault (SOTF) Trip Logic later in this section for more
information on switch-onto-fault logic.
TR Other Trip Conditions.
Setting TR is the SEL
OGIC
Control Equation trip setting most often used
if tripping does not involve communications-assisted (settings TRCOMM
and DTT) or switch-onto-fault (setting TRSOTF) trip logic.
Note in
Figure SECTION 5: .1 that setting TR is unsupervised. Any
element that asserts in setting TR will cause Relay Word bit TRIP to
assert to logical 1.
ULTR Unlatch Trip Conditions.
TDURD Minimum Trip Duration Time.
This timer establishes the minimum time duration for which the TRIP
Relay Word bit asserts. This is rising edge initiated timer. The settable
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