6.17
Date Code 20080213 Instruction Manual SEL-351A Relay
Close and Reclose Logic
Reclosing Relay
79OI2 = 600.00
79OI3 = 0.00
For this example:
Number of reclosures (last shot) = 2 = the number of set open interval
times that precede the first open interval set to zero.
Observe Shot Counter Operation (Only on Models With LCD)
Observe the reclosing relay shot counter operation, especially during testing,
with the front-panel shot counter screen (accessed via the {OTHER}
pushbutton). See Functions Unique to the Front-Panel Interface on page 11.6.
Reset Timer
The reset timer qualifies circuit breaker closure before taking the relay to the
Reset State from the Reclose Cycle State or the Lockout State. Circuit breaker
status is determined by the SEL
OGIC control equation setting 52A. (See Close
Logic on page 6.2 for more discussion on SEL
OGIC control equation setting
52A. Also see Optoisolated Inputs on page 7.2 for more discussion on
SEL
OGIC control equation setting 52A.)
Setting 79RSD
Qualifies closures when the relay is in the Reclose Cycle State. These closures
are usually automatic reclosures resulting from open interval time-out.
It is also the reset time used in sequence coordination schemes [see Sequence
Coordination Setting (79SEQ) on page 6.26].
Setting 79RSLD
Qualifies closures when the relay is in the Lockout State. These closures are
usually manual closures. These manual closures can originate external to the
relay, via the CLOSE command, or via the SEL
OGIC control equation setting
CL (see Figure 6.1).
Setting 79RSLD is also the reset timer used when the relay powers up, has
individual settings changed for the active setting group, or the active setting
group is changed (see Reclosing Relay States and Settings/Setting Group
Changes on page 6.14).
Typically, setting 79RSLD is set less than setting 79RSD. Setting 79RSLD
emulates reclosing relays with motor-driven timers that have a relatively short
reset time from the lockout position to the reset position.
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:
Courtesy of NationalSwitchgear.com
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