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4.84
SEL-787 Relay
Instruction Manual
Date Code 20081022
Protection and Logic Functions
Global Settings (SET G Command)
EXAMPLE 4.5
Setting MPTXxx With a Specified Location of Analog
Quantity
MPTX01 := THE LOAD CURRENT IS %.2f AMPERES
MPAQ01 value = 157.44
Formatted message out when triggered: THE LOAD CURRENT IS
157.44 AMPERES
MPTX01 := THE LOAD CURRENT IS %d AMPERES
MPAQ01 value = 157.44
Formatted message out when triggered: THE LOAD CURRENT IS 157
AMPERES
Group Selection
The TGR setting defines the amount of time that the SS1, SS2, SS3, and SS4
SEL
OGIC
control equation logic results must remain stable before the relay
enables a new setting group. Typically, a one-second delay is sufficient.
SS1, SS2, SS3, and SS4 are SEL
OGIC
control equations that help define when
setting Group 1, 2, 3, and 4 are active. With the settings shown above, SS1 is
set equal to logical 1, thus setting Group 1 always is active.
Synchrophasor
Measurement
The SEL-787 Transformer Protection Relay provides Phasor Measurement
Control Unit (PMCU) capabilities when connected to an IRIG-B time source.
See
for the
settings.
Breaker Failure
Setting
The SEL-787 provides flexible breaker failure logic (see
) for two
breakers. In the default breaker failure logic, assertion of trip Relay Word bits
associated with a breaker starts a BFD timer if the sum of positive and
negative-sequence breaker current is above 0.02 • I
NOM
. If the current remains
above the threshold for BFD delay setting, Relay Word bit BFT will assert.
Use the BFT to operate an output relay to trip appropriate backup breakers.
Table 4.34
Setting Group Selection
Setting Prompt
Setting Range
Setting Name :=
Factory Default
GRP CHG DELAY
0–400 sec
TGR := 3
SELECT GROUP1
SEL
OGIC
SS1 := 1
SELECT GROUP2
SEL
OGIC
SS2 := 0
SELECT GROUP3
SEL
OGIC
SS3 := 0
SELECT GROUP4
SEL
OGIC
SS4 := 0
Table 4.35
Breaker Failure Setting
Setting Prompt
Setting Range
Setting Name := Factory Default
52A INTERLOCK
Y, N
52ABF := N
BRKR1 FAIL DELAY
0.00–2.00 sec
BFD1 := 0.50
BRKR1 FAIL INIT
SEL
OGIC
BFI1 := R_TRIG TRIP1 OR
R_TRIG TRIPXFMR
BRKR2 FAIL DELAY
0.00-2.00 sec
BFD2 := 0.50
BRKR2 FAIL INIT
SEL
OGIC
BFI2 := R_TRIG TRIP2 OR
R_TRIG TRIPXFMR
Summary of Contents for SEL-787
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