6.140
SEL-421 Relay Instruction Manual Date Code 20171021
Protection Applications Examples
Autoreclose Example
Enable the voltage check elements.
EVCK := Y. Reclosing Voltage Check (Y, N)
Set the dead line voltage threshold equal to 15 V secondary.
27LP := 15.0. Dead Line Voltage (1.0–200 V secondary)
Set the live line voltage threshold equal to 50 V secondary.
59LP := 50.0. Live Line Voltage (1.0–200 V secondary)
Set the dead bus voltage threshold for Circuit Breaker 1 equal to 15 V secondary.
27BK1P := 15.0. Breaker 1 Dead Busbar Voltage (1.0–200 V secondary)
Set the live bus voltage threshold for Circuit Breaker 1 equal to 50 V secondary.
59BK1P := 50.0. Breaker 1 Live Busbar Voltage (1.0–200 V secondary)
Example Complete
This completes the application example that describes setting the SEL-421 for
one shot of three-pole reclosing for a single circuit breaker. Analyze your partic-
ular power system to determine the appropriate settings for your application.
Relay Settings
Table 6.39 provides a list of all the SEL-421 autoreclose settings. Those settings
that were applied for this particular application appear in boldface.
Figure 6.36 Potential Sources
SEL-421
1
3
Line
Disconnect
(Line Potential)
(Bus Potential)
VAZ
VY
BK1
Table 6.39 Settings for Autoreclose Example (Sheet 1 of 2)
Setting Prompt Entry
Relay Configuration
E79 Reclosing (Y, Y1, N) Y
Recloser Closing (Group)
NSPSHOT Number of Single-Pole Reclosures (N, 1, 2) N
N3PSHOT Number of Three-Pole Reclosures (N, 1–4) 1
E3PR1 Three-Pole Reclose Enable—BK1 (SELOGIC Equation) IN106
BKCFD Breaker Close Failure Delay (OFF, 1–99999 cycles) 600
ULCL1 Unlatch Closing for Breaker 1(SEL
OGIC Equation) 52AA1
79DTL Recloser Drive to Lockout (SEL
OGIC Equation) LOP
79BRCT Block Reclaim Timer (SEL
OGIC Equation) NA
To Next Page
Loading...
