Schweitzer Engineering Laboratories SEL-421-4 - Table 5.81 Synchronism-Check Relay Word Bits; Figure 5.121 Synchronism-Check Relay Word Bits

5.161
Date Code 20171021 Instruction Manual SEL-421 Relay
Protection Functions
Synchronism Check
Figure 5.121 Synchronism-Check Relay Word Bits
Table 5.81 Synchronism-Check Relay Word Bits (Sheet 1 of 2)
Relay
Word Bit
Description
59VP V
P
within healthy voltage window
59VS1 V
S1
within healthy voltage window
59VDIF1 Circuit Breaker BK1 synchronizing voltage difference less than limit
25ENBK1 Circuit Breaker BK1 synchronism-check element enabled
SFZBK1 Circuit Breaker BK1 slip frequency less than 0.005 Hz (“no slip” condition)
SFBK1 0.005 Hz  Circuit Breaker BK1 slip frequency < 25SFBK1
25W1BK1 Voltage angle across Circuit Breaker BK1 < ANG1BK1
25W2BK1 Voltage angle across Circuit Breaker BK1 < ANG2BK1
25A1BK1 Same operation as 25W1BK1, except for the restrictive operation (0° closure attempt)
when setting 25SFBK1  OFF and the system is slipping (see Figure 5.130)
25A2BK1 Same operation as 25W2BK1, except for the restrictive operation (0° closure attempt)
when setting 25SFBK1  OFF and the system is slipping (see Figure 5.130)
FAST1 Bus 1 frequency greater than line frequency (f
S1
> f
P
)
SLOW1 Bus 1 frequency less than line frequency (f
S1
< f
P
)
59VS2 V
S2
within healthy voltage window
59VDIF2 Circuit Breaker BK2 synchronizing voltage difference less than limit
25ENBK2 Circuit Breaker BK2 synchronism-check element enabled
SFZBK2 Circuit Breaker BK2 slip frequency less than 0.005 Hz (“no slip” condition)
SFBK2 0.005 Hz  Circuit Breaker BK2 slip frequency < 25SFBK2
25W1BK2 Voltage angle across Circuit Breaker BK2 < ANG1BK2
25W2BK2 Voltage angle across Circuit Breaker BK2 < ANG2BK2
Bus 2
Bus 1
Synchronism-Check Voltage Source 1
59VS1 — V
S1
healthy
Synchronism-Check Voltage Reference
59VP — V
P
healthy
Synchronism-Check Voltage Source 2
59VS2 — V
S2
healthy
Line
Synchronism-Check Across Breaker BK1
25ENBK1 — synchronism enabled
SFZBK1 — no slip
SFBK1 — slip < 25SFBK1
FAST1 — f
S1
> f
P
SLOW1 — f
S1
< f
P
25W1BK1 — synchronism within ANG1BK1
25A1BK1 — variation of 25W1BK1
25W2BK1 — synchronism within ANG2BK1
25A2BK1 — variation of 25W2BK1
Synchronism-Check Across Breaker BK2
25ENBK2 — synchronism enabled
SFZBK2 — no slip
SFBK2 — slip < 25SFBK2
FAST2 — f
S2
> f
P
SLOW2 — f
S2
< f
P
25W1BK2 — synchronism within ANG1BK2
25A1BK2 — variation of 25W1BK2
25W2BK2 — synchronism within ANG2BK2
25A2BK2 — variation of 25W2BK2
BK2
BK1
3
11
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