4.69
Date Code 20150130 Instruction Manual SEL-787 Relay
Protection and Logic Functions
Trip/Close Logic
REMTRIP Remote Trip Conditions SELOGIC Control Equation
You can map any Relay Word bit or SELOGIC equation to the REMTRIP to
trip a breaker or the transformer. For example, you can map a control input to
REMTRIP and map the REMTRIP to appropriate TRm equation.
Unlatch Trip Logic
Each of the three trip logic equations has an associated unlatch trip SELOGIC
equation. Following a fault, the appropriate trip signal is maintained until all
of the following conditions are true:
NOTE: The factory-default setting of
the ULTRIP provides an automatic
reset of the trip when the breaker
opens and selected 50/51 elements
are not picked up.
➤ Minimum trip duration time (TDURD) passes.
➤ The TRm (m =1,2, XFMR) SELOGIC control equation result
deasserts to logical 0.
➤ One of the following occurs:
➢ Unlatch Trip SELOGIC control equation setting
ULTRIP asserts to logical 1.
➢ Target Reset SELOGIC control equation setting
RSTTRGT asserts to logical 1.
➢ Target Reset Relay Word TRGTR asserts. The TRGTR
is asserted when the front-panel TARGET RESET
pushbutton is pressed or a target reset serial port
command is executed (ASCII, Modbus, or DeviceNet).
52A Breaker Status Conditions SELOGIC Control Equations
You can connect an auxiliary contact of the high and low side breaker to the
relay. The
SELOGIC control equations 52A1 and 52A2 allow you to configure
the relay for either 52b or 52a contact input (or other contact that indicates a
closed breaker). The factory-default setting assumes no auxiliary contact
connection (both 52A1 and 52A2 := 0).
If you connect the breaker auxiliary contact to a digital input, you must change
the factory-default logic equation. For example, set 52A1 := IN101 if you
connect the 52a contact of breaker 52-1 to input IN101.
Figure 4.51 shows a close logic diagram of breaker 52-1; the logic of breaker
52-2 is similar.
Figure 4.51 Close Logic
CFD1
0
CL1
ULCL1
CLOSE1
CF1
Close Failure Timer
SEL
OGIC
Equations
52A1
Relay
Word
Bits
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