Schweitzer Engineering Laboratories SEL-587Z - Example 4.8 Transformer Settings Example

4.15
Date Code 20020903 SEL-587Z Instruction Manual
Control Logic
SEL
OGIC Control Equation Variables/Timers
EXAMPLE 4.8 Transformer Settings Example
When the SEL-587Z is used as transformer protection, configure a
dedicated breaker failure protection element as follows (see
Figure 4.6):
SV6 = TR1*50P1 SELOGIC Variable SV6
SV7 = TR1*50P1 SELOGIC Variable SV7
Retrip:
OUT1 = SV6T Output Contact OUT1
Breaker failure trip:
OUT2 = SV7T Output Contact OUT2
Figure 4.6 Breaker Failure Function Created
With SEL
OGIC Control Equation Variables/Timers.
TR1 functions as a breaker failure initiate input. Phase instantaneous
overcurrent element 50P1 functions as the fault detector.
Timer pickup setting SV6PU provides retrip delay, if desired (can be
set to zero).
Timer pickup setting SV7PU provides breaker failure timing. Timer
dropout setting SV7DO holds the breaker failure trip output (output
contact OUT2) closed for extra time if needed after the breaker
failure logic unlatches (fault detector 50P1 or TR1 drops out).
TR1
50
P
1
S
V7
T
S
V
7
S
V
6
S
V
6T
S
V
6
P
U
S
V
6
D
O
S
V7P
U
S
V7D
O
OU
T1
(Retri
p)
OU
T2
(
Breaker
F
a
il
u
r
e
Tri
p)