Sel 411L - Figure 4.26 Healthy Voltage Window and Indication; Figure 4.27 Synchronism-Check Enable Logic

P.4.56
SEL-411L Relay Protection Manual Date Code 20151029
Autoreclosing and Synchronism-Check
Synchronism Check
Figure 4.26 Healthy Voltage Window and Indication
Block Synchronism-Check
If the block synchronism-check BSYNBKn SELOGIC control equation (where
n = 1 or 2 for Circuit Breaker BK1 or Circuit Breaker BK2, respectively)
asserts, synchronism-check cannot proceed for the corresponding circuit
breaker. Following is an example for Circuit Breaker BK1:
BSYNBK1 := 52AA1 AND 52AB1 AND 52AC1 Block Synchronism-Check—BK1
(SEL
OGIC Equation)
If Circuit Breaker BK1 is closed, the three-pole indication back to the relay
shows 52AA1 equals 52AB1 equals 52AC1 equals logical 1. Thus,
BSYNBK1 equals logical 1, and synchronism-check is blocked for Circuit
Breaker BK1. There is no need to qualify or continue with the synchronism-
check for circuit breaker closing; the circuit breaker is already closed.
Synchronism-Check Enable Logic
The relay combines the voltage check elements and block synchronism-check
condition to create a synchronism-check enable condition for each circuit
breaker, as shown in Figure 4.27.
Figure 4.27 Synchronism-Check Enable Logic
V
S1
V
S2
25VL=60
25VH=73
59VS1 =
logical 1
59VP =
logical 1
59VS2 =
logical 1
Voltage
magnitude
(V
P
base)
Corresponding
Relay
Word Bits:
V
P
6
CYC
59VP
59VS1
BSYNBK1
V
P
healthy
V
S1
healthy
Block synchronism check for Circuit Breaker BK1
0
25ENBK1
(Enable synchronism check
for Circuit Breaker BK1)
SEL OGIC
Setting
6
CYC
59VP
59VS2
BSYNBK2
Relay
Word
Bits
Relay
Word
Bits
Relay
Word
Bits
Relay
Word
Bits
V
P
healthy
V
S2
healthy
Block synchronism check for Circuit Breaker BK2
0
25ENBK2
(Enable synchronism check
for Circuit Breaker BK2)
SEL OGIC
Setting