Schweitzer Engineering SEL-351P - Start Loss of Load Diversity Timer

1-8 Factory-Set Logic Date Code 990215
SEL-351P Manual Técnico
cold load pickup scheme
actively engaged for at
least one element
phase
SEF
ground
restore min. trips scheme
enabled for at least one
element
phase
SEF
ground
SV5
PU
0
restore
min. trips
time limit
SV5
lockout state
reclose cycle state
reset state
reclosing
relay
defeated
SV6
PU
0
loss of
load
diversity
time
SV6
SV5T
(restore
min. trips)
SV6T
(loss of
load
diversity)
cold load pickup scheme enabled
for phase or ground elements
SEL OGIC
Settings
Relay
Word
Bits
Rela
y
Word
Bits
SV8
SV10
SV12
RPP
RPG
RPS
52A
recloser closed
79LO
79CY
79RS
CLP
DWG: M351R026
CLG
79RS
phase
ground
Figure SECTION 1: .1: Loss of Load Diversity (top) and Restore Min. Trips
(bottom) Logic for Cold Load Pickup Scheme
Start Loss of Load Diversity Timer
Loss of load diversity timer SV6PU in
Figure SECTION 1: .1 starts timing when both the
following conditions are true:
• Recloser is open (Relay Word bit 52A = logical 0)
• SEL-351P is in the lockout state (Relay Word bit 79LO = logical 1) or
the reclosing
relay is defeated
EZ setting Reclose interval 1 = 0 (SET EZ command) or enable setting E79 = N (SET n
command) defeats the reclosing relay (it is effectively nonexistent; Relay Word bits 79RS =
79CY = 79LO = logical 0).
When SV6PU times out, Relay Word bit SV6T asserts to logical 1, indicating a loss of load
diversity condition. SV6T propagates to the logic in
Figure SECTION 1: .2 through Figure
SECTION 1: .4 for phase, ground, and SEF overcurrent elements, respectively. The logic in
these three figures operates similarly – let’s examine the operation of
Figure SECTION 1: .2
(phase).