Schweitzer Engineering Laboratories SEL-351A - Figure 6.8 Sequence Coordination between the SEL-351 A and a Line Recloser; Figure 6.9 Operation of SEL-351 A Shot Counter for Sequence Coordination

6.27
Date Code 20080213 Instruction Manual SEL-351A Relay
Close and Reclose Logic
Reclosing Relay
Figure 6.8 Sequence Coordination Between the SEL-351A and a Line
Recloser
Assume that the line recloser is set to operate twice on the fast curve and then
twice on the slow curve. The slow curve is allowed to operate after two fast
curve operations because the fast curves are then inoperative for tripping. The
SEL-351A phase time-overcurrent element 51PT is coordinated with the line
recloser fast curve. The SEL-351A single-phase time-overcurrent elements
51AT, 51BT, and 51CT are coordinated with the line recloser slow curve.
q Fault occurs beyond line recloser; w fault cleared by line recloser fast curve; e line recloser recloses into fault; r fault
cleared by line recloser slow curve.
Figure 6.9 Operation of SEL-351A Shot Counter for Sequence Coordination With Line Recloser (Additional
Settings Example 1)
Fast Curve
(Line Recloser)
51P1
Slow Curve
(Line Recloser)
t
I
F
I
51P1T
(SEL-351)
51AT, 51BT, 51CT
(SEL-351)
SEL-351
R
Line Recloser
I
F
79SEQ = 79RS * 51P1
SH0 + SH1
SH1
SH0
Shot Counter 0 1 2 3
4
qw ew e r e r
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