Sel 751A, Инструкция по эксплуатации

Страница: 165 / 640

4.73
Date Code 20100129 Instruction Manual SEL-751A Relay
Protection and Logic Functions
Reclose Logic
further than shot = 4. The shot counter returns to shot = 0 after the reset timer
times out. Reset timing is subject to SEL
OGIC
control equation setting 79BRS
[see Block Reset Timing Setting (79BRS) on page 4.71 ].
Sequence coordination operation does not change the reclosing relay state. For
example, if the relay is in the Reset State and there is a sequence coordination
operation, it remains in the Reset State.
EXAMPLE 4.18 Factory Settings Example
Sequence coordination is not enabled in the factory settings:
79SEQ := 0
EXAMPLE 4.19 Additional Settings Example 1
With sequence coordination setting:
79SEQ := 79RS AND 51P1P
sequence coordination is operable only when the relay is in the Reset
State (79RS = logical 1). Refer to
Figure 4.37 and Figure 4.38 .
Figure 4.37 Sequence Coordination Between the SEL-751A 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-751A phase time-overcurrent
element 51P1T is coordinated with the line recloser fast curve. The
SEL-751A single-phase time-overcurrent elements 51AT, 51BT, and
51CT are coordinated with the line recloser slow curve.
Fast Curve
(Line Recloser)
51P1
Slow Curve
(Line Recloser)
t
IF I
51P1T
(SEL-751A)
51AT, 51BT, 51CT
(SEL-751A)
SEL-751A
R
Line Recloser
I
F