Schweitzer Engineering Laboratories SEL-311L, Instruction Manual, Page: 225 / 734

Date Code 20010625 Close and Reclose Logic 6-7
SEL-311L Instruction Manual
Settings and General Operation
Figure 6.2 contains the following SEL
OGIC
control equation setting:
79CLS (reclose supervision conditions—checked after reclosing relay open interval time-
out)
and setting:
79CLSD (Reclose Supervision Limit Time)
See the settings sheets at the end of Section 9: Setting the Relay for setting ranges.
For Most Applications (Top of Figure 6.2)
For most applications, the Reclose Supervision Limit Time setting should be set to zero cycles:
79CLSD = 0.00
With this setting, the logic in the top of Figure 6.2 is operative. When an open interval times out,
the SEL
OGIC
control equation reclose supervision setting 79CLS is checked just once.
If 79CLS is asserted to logical 1 at the instant of an open interval time-out, then the open interval
time-out will propagate onto the final close logic in Figure 6.1 to automatically reclose the
circuit breaker.
If 79CLS is deasserted to logical 0 at the instant of an open interval time-out, the following
occurs:
•
No automatic reclosing takes place.
•
Relay Word bit RCSF (Reclose Supervision Failure indication) asserts to logical 1 for
one processing interval.
•
The reclosing relay is driven to the Lockout State.
See Settings Example and Additional Settings Example 1 that follow in this subsection.
For a Few, Unique Applications (Bottom of Figure 6.2 and Figure 6.3)
For a few unique applications, such as slip between two systems, the Reclose Supervision Limit
Time setting is not set equal to zero cycles:
e.g., 79CLSD = 60.00
With this setting, the logic in the bottom of Figure 6.2 is operative. When an open interval times
out, the SEL
OGIC
control equation reclose supervision setting 79CLS is then checked for a time
window equal to setting 79CLSD.
If 79CLS asserts to logical 1 at any time during this 79CLSD time window, then the open
interval time-out will propagate onto the final close logic in Figure 6.1 to automatically reclose
the circuit breaker.