6.177
Date Code 20171021 Instruction Manual SEL-421 Relay
Protection Applications Examples
230 kV Tapped Transmission Line Application Example
PST02R Protection Sequence Timer 2 reset PST02R := PLT01
PST02IN Protection Sequence Timer 2 enable PST02IN := PSV02 AND IN103 230 kV bus is dead AND MOD is open
PST03PT Protection Sequence Timer 3 preset PST03PT := 3600.00 MOD latch reset if:
PST03R Protection Sequence Timer 3 reset PST03R := NOT PLT01
PST03IN Protection Sequence Timer 3 enable PST03IN := PSV01 AND IN101 AND
IN102
230 kV bus is hot AND BK1T AND
BK2T are open for 60 s
PST04PT Protection Sequence Timer 4 preset PST04PT := 330.00 Pulse close the MOD if:
PST04R Protection Sequence Timer 4 reset PST04R := NOT PSV01 OR NOT
IN101 OR NOT IN102 OR NOT IN103
OR PLT01 OR PST04Q
230 kV bus is not hot OR BK1T OR
BK2T is closed OR MOD is closed OR
PST04 output equals logical 1
PST04IN Protection Sequence Timer 4 enable PST04IN := PSV01 AND IN101 AND
IN102 AND IN103 AND NOT PLT01
230 kV bus is hot AND BK1T AND
BK2T are open AND MOD is open
AND MOD latch reset
OUT106* Output 106 AND NOT PCN02Q PST04ET > 300.00 AND NOT PCN02Q MOD close command
PCN01PV Protection Counter 1 preset PCN01PV := 2 MOD block trip if:
PCN01R Protection Counter 1 reset PCN01R := IN103
PCN01IN Protection Counter 1 enable PCN01IN := OUT103 Two trips without MOD open
PCN02PV Protection Counter 2 preset PCN02PV := 2 MOD block close if:
PCN02R Protection Counter 2 reset PCN02R := NOT IN103
PCN02IN Protection Counter 2 enable PCN02IN := OUT106 Two closes without MOD closed
PCT01PU Protection Conditioning Timer 1
Pickup
240.00
PCT01DO Protection Conditioning Timer 1
Dropout
0.00
PCT01IN Protection Conditioning Timer 1
Enable
NOT IN103 AND 25A1BK1 OR PLT01
AND IN103 AND 59VS1
MOD is closed AND synchronized OR
MOD latch set AND MOD is open
AND BK1T bus is hot for 4 s
PCT02PU Protection Conditioning Timer 2
Pickup
240.00
PCT02DO Protection Conditioning Timer 2
Dropout
0.00
PCT02IN Protection Conditioning Timer 2
Enable
NOT IN103 AND 25A1BK2 AND NOT
IN101 OR PLT01 AND IN103 AND
59VS2 AND NOT IN101
MOD is closed AND synchronized
AND BK1T is closed OR MOD latch
set AND MOD is open AND BK2T bus
is hot AND BK11T is closed for 4 s
a
This control output assignment is not a protection freeform SELOGIC control equation, but appears in this table for continuity of the overall
logic.
Table 6.48 Protection Freeform SELOGIC Control Equations (Sheet 2 of 2)
Setting Description Entry Comments
=>> SHO L <Enter>
Protection 1
Free-Form Protection SELogic
1: ### PROTECTION FREE-FORM AUTOMATION EXAMPLE
2: ###
3: ### SET CONTROL VARIABLE 1
4: ### ASSERTS WHEN PRIMARY POSITIVE SEQUENCE VOLTAGE IS
5: ### GREATER THAN 90% OF NOMINAL
Figure 6.53 Protection Free-Form SELOGIC Control Equations
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