Sel 551 - Figure 3.16 Reclosing Sequence from Reset to Lockout with Factory Settings

3.25
Date Code 20110408 Instruction Manual SEL-551 Relay
Relay Elements and Logic
Reclosing Relay
Reclosing Relay
Timer Settings
The open interval and reset timer factory settings are:
The operation of these timers is affected by SEL
OGIC control equation settings
discussed later in this section. Also see the setting sheets in Section 4: Setting
the Relay.
Open Interval Timers
If an open interval time is set to zero, then that open interval time is not
operable, and neither are the open intervals times that follow it.
In the above factory settings, the open interval time setting 79OI3 is the first
open interval time setting set equal to zero:
79OI3 = 0.000 cycles
Thus, open interval times 79OI3 and 79OI4 are not operable. In the factory
settings, both open interval times 79OI3 and 79OI4 are set to zero. But if the
settings were:
79OI3 = 0.000 cycles
79OI4 = 900.000 cycles (set to some value other than zero)
open interval time 79OI4 would still be inoperative, because a preceding open
interval time is set to zero (i.e., 79OI3 = 0.000).
If open interval time setting 79OI1 is set to zero (79OI1 = 0.000 cycles), no
open interval timing takes place, and the reclosing relay is rendered
nonexistent.
The open interval timers time consecutively; they do not have the same
beginning time reference point. In the above factory settings, the open interval
time setting 79OI1 times first. If the subsequent first reclosure is not
successful, then open interval time setting 79OI2 times. If the subsequent
second reclosure is not successful, the relay goes to the Lockout State. See the
example time-line Figure 3.16.
Figure 3.16 Reclosing Sequence From Reset to Lockout With Factory Settings
Timer Setting
Factory Setting
(in cycles)
Definition
79OI1 30.000 open interval 1 time
79OI2 600.000 open interval 2 time
79OI3 0.000 open interval 3 time
79OI4 0.000 open interval 4 time
79RSD 1800.000 reset time from reclose cycle state
79RSLD 300.000 reset time from lockout state
Open Interval Time-out
Shot
Counter
0
52A
79OI1 = 30
Reset State
Trip Close Trip Close Trip
Reclose Cycle State Lockout State
(79OI3 = 0)
79OI2 = 600
(Last Shot = 2)
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