Schweitzer Engineering Laboratories SEL-351-5, Instruction Manual

Page: 256 / 706

6.18
SEL-351-5, -6, -7 Relay Instruction Manual
Date Code 20070117
Close and Reclose Logic
Reclosing Relay
The 79RSD and 79RSLD settings are set independently (setting 79RSLD can
even be set greater than setting 79RSD, if desired). SEL
OGIC
control equation
setting 79BRS (block reset timing) can be set to control reset timing [see
Block Reset Timing Setting (79BRS) on page 6.25 ].
Monitoring Open Interval and Reset Timing
Open interval and reset timing can be monitored with the following Relay
Word bits:
If the open interval timer is actively timing, OPTMN asserts to logical 1.
When the relay is not timing on an open interval (e.g., it is in the Reset State or
in the Lockout State), OPTMN deasserts to logical 0. The relay can only time
on an open interval when it is in the Reclose Cycle State, but just because the
relay is in the Reclose Cycle State does not necessarily mean the relay is
timing on an open interval. The relay only times on an open interval after
successful reclose initiation and no stall conditions are present [see
Skip Shot
and Stall Open Interval Timing Settings (79SKP and 79STL, Respectively) on
page 6.23
].
If the reset timer is actively timing, RSTMN asserts to logical 1. If the reset
timer is not timing, RSTMN deasserts to logical 0. See
Block Reset Timing
Setting (79BRS) on page 6.25 .
Reclosing Relay Shot
Counter
Refer to Figure 6.6 .
The shot counter increments for each reclose operation. For example, when
the relay is timing on open interval 1, 79OI1, it is at shot = 0. When the open
interval times out, the shot counter increments to shot = 1 and so forth for the
set open intervals that follow. The shot counter cannot increment beyond the
last shot for automatic reclosing [see
Determination of Number of Reclosures
(Last Shot) on page 6.17 ]. The shot counter resets back to shot = 0 when the
reclosing relay returns to the Reset State.
When the shot counter is at a particular shot value (e.g., shot = 2), the
corresponding Relay Word bit asserts to logical 1 (e.g., SH2 = logical 1).
The shot counter also increments for sequence coordination operation. The
shot counter can increment beyond the last shot for sequence coordination
[see
Sequence Coordination Setting (79SEQ) on page 6.26 ].
Relay Word Bits Definition
OPTMN Indicates that the open interval timer is actively timing
RSTMN Indicates that the reset timer is actively timing
Table 6.3 Shot Counter Correspondence to Relay Word Bits and Open
Interval Times
Shot
Corresponding Relay
Word Bit
Corresponding Open
Interval
0 SH0 79OI1
1 SH1 79OI2
2 SH2 79OI3
3 SH3 79OI4
4 SH4