6–94
350 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL
S3 PROTECTION
CHAPTER 6: SETPOINTS
Figure 6-41: Thermal Overload protection logic diagram
SETPOINTS
Phase
A current
(IA
)
RUN
SETPOINT
FUNCTION
Disabled
=
0
Latched
Alarm
PICKUP
AND
Phase B current (IB
)
Phase C current (IC)
Operate Output Relay
1
(TRIP)
LED:
TRIP
Event Recorder
Transient Recorder
Alarm
OR
OR
Phase Currents
AND
SETPOINT
OUTPUT
RELA
Y X
Trip
AND
SETPOINT
BLOCK
1:
Of
f=
0
BLOCK
2:
Of
f=
0
BLOCK
3:
Of
f=
0
OR
Message
THERMAL OVERLOAD
Ph
A
Thermal OP
Ph B
Thermal OP
Ph C
Thermal OP
OR
Trip
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
V
ALUES
Ph
A
Thermal
Alarm
Message
OR
SETPOINT
ALARM
ALARM
θ
θ>
Ph B
Thermal
Alarm
Ph C
Thermal
Alarm
LED
:ALARM
RESET
Command
AND
S
R
LA
TCH
Event Recorder
Transient Recorder
898762A1.CDR
Do Not Operate, Operate