Schweitzer Engineering Laboratories SEL-351 - Other Settings Considerations; Drive-To-Lockout and Drive-To-Last Shot Settings (79 DTL and 79 DLS, Respectively); Factory Settings Example

6-22 Close and Reclose Logic Date Code 20001006
SEL-351 Instruction Manual
Other Settings Considerations
1. In the preceding additional setting example, the reclose initiate setting (79RI) includes input
IN1, that is connected to a 52a breaker auxiliary contact (52A = IN1).
79RI = !52A
If a 52b breaker auxiliary contact is connected to input IN1 (52A = !IN1), the reclose initiate
setting (79RI) remains the same.
2. If no reclose initiate supervision is desired, make the following setting:
79RIS = 1 (numeral 1)
Setting 79RIS = logical 1 at all times. Any time a logical 0 to logical 1 transition is detected by
setting 79RI, open interval timing will be initiated (unless prevented by other means).
3. If the following setting is made:
79RI = 0 (numeral 0)
reclosing will never take place (reclosing is never initiated). The reclosing relay is effectively
inoperative.
4. If the following setting is made:
79RIS = 0 (numeral 0)
reclosing will never take place (the reclosing relay goes directly to the lockout state any time
reclosing is initiated). The reclosing relay is effectively inoperative.
Drive-to-Lockout and Drive-to-Last Shot Settings (79DTL and 79DLS, Respectively)
When 79DTL = logical 1, the reclosing relay goes to the Lockout State (Relay Word bit
79LO = logical 1), and the front-panel LO (Lockout) LED illuminates.
79DTL has a 60-cycle dropout time. This keeps the drive-to-lockout condition up 60 more cycles
after 79DTL has reverted back to 79DTL = logical 0. This is useful for situations where both of
the following are true:
• Any of the trip and drive-to-lockout conditions are “pulsed” conditions (e.g., the OPEN
Command Relay Word bit, OC, asserts for only 1/4 cycle – refer to the following Factory
Settings Example).
• Reclose initiation is by the breaker contact opening (e.g., 79RI = !52A – refer to
Additional Settings Example in the preceding setting 79RI [reclose initiation]
discussion).
Then the drive-to-lockout condition overlaps reclose initiation and the SEL-351 stays in lockout
after the breaker trips open.
When 79DLS = logical 1, the reclosing relay goes to the last shot, if the shot counter is not at a
shot value greater than or equal to the calculated last shot (see Reclosing Relay Shot Counter
earlier in this subsection).
Courtesy of NationalSwitchgear.com