
CHAPTER 6: SETPOINTS
S3 PROTECTION
350 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL
6–113
Figure 38: Thermal model protection logic diagram
SETPOINTS
Phase
A
current
(IA)
RUN
SETPOINT
THERMAL
MDL
FUNC
Disabled
=
0
Latched
Alarm
THERMAL
MDL
PICKUP
AND
Phase
B
current
(IB)
Phase
C
current
(IC)
Operate
Output
Relay
1
(TRIP)
LED:
TRIP
Event
Recorder
T
ransient
Recorder
Alarm
OR
OR
Phase
Currents
AND
SETPOINT
:
Operate
output
relays
upon
selection
OUTPUT
RELA
Y
4
OUTPUT
RELA
Y
5
OUTPUT
RELA
Y
6
OUTPUT
RELA
Y
3
T
rip
AND
SETPOINT
BLOCK
1:
O
ff=0
BLOCK
2:
O
ff=0
BLOCK
3:
O
ff=0
OR
Message
THERMAL
MODEL
Ph
A
Thermal
OP
Ph
B
Thermal
OP
Ph
C
Thermal
OP
OR
T
rip
HEA
TING
T
.
CONST
ANT
COOLING
T
.
CONST
ANT
T
TRIP
(ph
B)
T
TRIP
(ph
C)
T
TRIP
(ph
A)
Thermal
Capacity
ph
A,
%
Thermal
Capacity
ph
B,
%
Thermal
Capacity
ph
C,
%
ACTUAL
VALUES
Ph
A
Thermal
Alarm
Message
OR
SETPOINT
THERMAL
MDL
ALARM
ALARM
q
q>
Ph
B
Thermal
Alarm
Ph
C
Thermal
Alarm
LED:
ALARM
RESET
Command
AND
S
R
LA
TCH
Event
Recorder
T
ransient
Recorder
898762.cdr