Schweitzer Engineering Laboratories SEL-421-4 - Table 6.40 Settings for Autoreclose and Synchronism Check Example

6.149
Date Code 20171021 Instruction Manual SEL-421 Relay
Protection Applications Examples
Autoreclose and Synchronism-Check Example
You do not need to shift the angle of the synchronism check because both the
source and reference voltage are measured A-Phase-to-neutral.
KS2A := 0. Synch Source 2 Angle Shift (0, 30, 60, 90, 120, 150, 180, 210, 240,
270, 300, 330 degrees)
There is no alternate synchronism source for Circuit Breaker 2 in this application
example.
ALTS2 := NA. Alternative Synch Source 2 (SELOGIC Equation)
Assume that there is no slip between the source and reference voltages.
25SFBK2 := OFF. Maximum Slip Frequency—BK2 (OFF, 0.005–0.5 Hz)
Set the maximum allowable voltage angular difference between the source and
reference voltages equal to 20 degrees when attempting to reclose Circuit
Breaker 2.
ANG1BK2 := 20.0. Maximum Angle Difference 1—BK2 (3.0–80 degrees)
Set the maximum allowable voltage angular difference between the source and
reference voltages equal to 20 degrees when attempting to manually close Circuit
Breaker 2.
ANG2BK2 := 20.0. Maximum Angle Difference 2—BK2 (3.0–80 degrees)
The relay does not compensate the synchronism check to account for circuit
breaker closing time because setting 25SFBK2 is OFF. Leave the close time com-
pensation setting at the default.
TCLSBK2 := 1.00. Breaker 2 Close Time (1.00–30 cycles)
Block the synchronism check if Circuit Breaker 2 is closed.
BSYNBK2 := 52AA2 AND 52AB2 AND 52AC2. Block Synchronism Check—
BK2 (SEL
OGIC Equation)
Example Complete
This completes the application example that describes setting the SEL-421 for
one shot of high-speed single-pole reclosing and one shot of three-pole reclosing
for two circuit breakers. This example showed a configuration for synchronism
check, as well. Analyze your particular power system to determine the appropri-
ate settings for your application.
Relay Settings
Table 6.40 provides a list of all the SEL-421 autoreclose settings.
Table 6.40 Settings for Autoreclose and Synchronism Check Example
(Sheet 1 of 3)
Setting Prompt Entry
Recloser Closing (Group)
E79 Reclosing (Y, Y1, N) Y
NSPSHOT Number of Single-Pole Reclosures (N, 1, 2) 1
ESPR1 Single-Pole Reclose Enable—BK1 (SEL
OGIC Equation) IN205
ESPR2 Single-Pole Reclose Enable—BK2 (SEL
OGIC Equation) IN206