6.12
SEL-351A Relay Instruction Manual Date Code 20080213
Close and Reclose Logic
Reclosing Relay
Reclosing Relay
Note that input:
Reclosing Relay Open Interval Time-Out
in Figure 6.2 is the logic input that is qualified by SEL
OGIC control equation
setting 79CLS, and then propagated on to the close logic in Figure 6.1 to
automatically reclose a circuit breaker. The explanation that follows in this
reclosing relay subsection describes all the reclosing relay settings and logic
that eventually result in this open interval time-out logic input into Figure 6.2.
Other aspects of the reclosing relay are also explained. Up to four (4)
automatic reclosures (shots) are available.
The reclose enable setting, E79, has setting choices N, 1, 2, 3, 4, C1, C2, C3,
and C4. Setting E79 = N defeats the reclosing relay. Setting choices 1–4 are
the number of desired automatic reclosures (see Open Interval Timers on
page 6.16). Setting choices 1–4 also have the reclosing relay go to the Lockout
state upon reclose supervision failure (refer to Reclose Supervision Logic on
page 6.5).
Setting choice C1–C4 similarly are the number of desired automatic
reclosures (C1 for one reclosure, C2 for two reclosures, etc.). Setting choices
C1–C4, however, do not have the reclosing relay go to the Lockout state upon
reclose supervision failure. Instead, the reclosing relay increments the shot
counter and starts timing on the next open interval. This operation emulates a
rotating drum timer style reclosing relay—going onto the next open interval
time and reclose opportunity if supervising conditions for the present reclose
opportunity are not true. If the reclosing relay increments to the last shot value
(no more open intervals left; see Figure 6.6 and Table 6.3), the reclosing relay
is then driven to the Lockout State.
Reclosing Relay
States and General
Operation
Figure 6.5 explains in general the different states of the reclosing relay and its
operation.
Courtesy of NationalSwitchgear.com
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