6.8
SEL-311C Relay Instruction Manual Date Code 20060320
Close and Reclose Logic
Reclose Supervision Logic
then a reclosing relay open interval time-out seals in Figure 6.2. Then, when
79CLS asserts to logical 1, the sealed-in reclosing relay open interval time-out
condition will propagate through Figure 6.2 and on to the close logic in
Figure 6.1.
Unlatch Reclose Supervision Logic (Bottom of Figure 6.2)
Refer to the bottom of Figure 6.2. If the reclosing relay open interval time-out
condition is sealed-in, it stays sealed-in until one of the following occurs:
➤ The close logic output CLOSE (also see Figure 6.1) asserts
(Relay Word bit CLOSE = logical 1).
➤ The reclosing relay goes to the Lockout State (Relay Word bit
79LO = logical 1).
➤ The circuit breaker closes (52A = logical 1).
➤ The reclose initiation condition (79RI) makes a rising edge
(logical 0 to logical 1) transition.
➤ SELOGIC control equation setting 79CLS asserts (79CLS =
logical 1).
➤ The Reclose Supervision Limit Timer times out (Relay Word
bit RCSF = logical 1 for one processing interval).
The Reclose Supervision Limit Timer is inoperative if setting 79CLSD = OFF.
With 79CLSD = OFF, reclose supervision condition 79CLS is not time
limited. When an open interval times out, reclose supervision condition
79CLS is checked indefinitely until one of the other above unlatch conditions
comes true.
The unlatching of the sealed-in reclosing relay open interval time-out
condition by the assertion of SEL
OGIC control equation setting 79CLS
indicates successful propagation of a reclosing relay open interval time-out
condition on to the close logic in Figure 6.1.
See Additional Settings Example 2 on page 6.10.
Settings Example
Refer to the top of Figure 6.2.
The example setting for the SEL
OGIC control equation reclose supervision
setting is:
79CLS = 1 (numeral 1)
The example setting for the Reclose Supervision Limit Timer setting is:
79CLSD = 0.00 cycles
Any time a reclosing relay open interval times out, it propagates immediately
through Figure 6.2 and then on to Figure 6.1, because SEL
OGIC control
equation setting 79CLS is always asserted to logical 1. Effectively, there is no
special reclose supervision.
Additional
Settings Example 1
Refer to the top of Figure 6.2 and Figure 6.4.
SEL-311C relays are installed at both ends of a transmission line in a high-
speed reclose scheme. After both circuit breakers open for a transmission line
fault, the SEL-311C(1) Relay recloses circuit breaker 52/1 first, followed by
the SEL-311C(2) Relay reclosing circuit breaker 52/2, after a synchronism
check across circuit breaker 52/2.
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