Schweitzer Engineering Laboratories SEL-787, Instruction Manual

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4.68
SEL-787 Relay Instruction Manual Date Code 20081022
Protection and Logic Functions
Trip/Close Logic
Rolling demand meter response at “Time = 15 minutes” = 3.0/3 = 1.0 per unit.
Trip/Close Logic
Trip/Close Logic
Settings
The trip logic and close logic for the SEL-787 operate in a similar manner.
Each has a
SEL
OGIC
control equation setting to set or latch the logic and
another
SEL
OGIC
control equation setting to reset or unlatch the logic. Each
also has other elements or functions that will unlatch the logic. The output of
each logic is a Relay Word bit that can be assigned to operate output contacts,
or in any other manner for which a Relay Word bit can be used. The specifics
of each type of logic are discussed below.
Table 4.24 Trip/Close Logic Settings
Setting Prompt
Setting
Range
Setting Name := Factory Default
MIN TRIP TIME 0.0–400.0 sec TDURD := 0.5
CLOSE 1 FAIL DLY 0.0–400.0 sec CFD1 := 0.5
CLOSE 2 FAIL DLY 0.0–400.0 sec CFD2 := 0.5
TRIP 1 EQUATION SV TR1 := 50P11T OR 51P1T OR 51Q1T OR
NOT LT02 AND SV04T OR OC1
TRIP 2 EQUATION SV TR2 := 51P2T OR 51Q2T OR LT02 AND
SV04T OR OC2
TRIP XFMR EQN SV TRXFMR := 87R OR 87U
REMOTE TRIP EQN SV REMTRIP := 0
UNLATCH TRIP 1 SV ULTRIP1 := NOT (51P1P OR 51Q1P OR
52A1)
UNLATCH TRIP 2 SV ULTRIP2 := NOT (51P2P OR 51Q2P OR
52A2)
UNLATCH TRP XFMR SV ULTRXFMR := NOT (87R OR 87U)
BREAKER1 STATUS SV 52A1 := 0
CLOSE1 EQUATION SV CL1 := SV03T AND NOT LT02 OR CC1
UNLATCH CLOSE 1 SV ULCL1 := TRIP1 OR TRIPXFMR
BREAKER 2 STATUS SV 52A2 := 0
CLOSE 2 EQUATION SV CL2 := SV03T AND LT02 OR CC2
UNLATCH CLOSE 2 SV ULCL2 := TRIP2 OR TRIPXFMR