Date Code 20001006 Close and Reclose Logic 6-3
SEL-351 Instruction Manual
The CLOSE command is included in the close logic in the factory settings:
CL = … + CC
Relay Word bit CC asserts for execution of the CLOSE Command. See CLO Command
(Close Breaker) in Section 10: Serial Port Communications and Commands for more
information on the CLOSE Command. More discussion follows later on the factory
settings for setting CL.
If previous firmware versions of the SEL-351 Relay with the CLOSE command imbedded
in the close logic also have setting CL set as:
CL = … + CC
this would appear as a redundancy in inputting the CLOSE command into the close logic.
But, this is no problem - just a redundancy in logic. Thus, SEL-351 Relays with various
firmware versions can be set the same with respect to setting CL = … + CC.
If a user wants to supervise the CLOSE command with optoisolated input IN6, the
following setting is made:
CL = … + CC*IN6
With this setting, the CLOSE command can provide a close only if optoisolated input IN6
is asserted. This is just one CLOSE command supervision example - many variations are
possible.
Unlatch Close
If the CLOSE Relay Word bit is asserted at logical 1, it stays asserted at logical 1 until one of the
following occurs:
• The unlatch close condition asserts (ULCL = logical 1).
• The circuit breaker closes (52A = logical 1).
• The reclose initiation condition (79RI) makes a rising edge (logical 0 to logical 1)
transition.
• Or the Close Failure Timer times out (Relay Word bit CF = 1).
The Close Failure Timer is inoperative if setting CFD = OFF.
Factory Settings Example
The factory settings for the close logic SELOGIC Control Equation settings are:
52A = IN1
CL = CC + LB4
ULCL = TRIP
The factory setting for the Close Failure Timer setting is:
Courtesy of NationalSwitchgear.com
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