GE Multilin 345 - Page 171

CHAPTER 6: SETPOINTS S3 PROTECTION
345 TRANSFORMER PROTECTION SYSTEM – INSTRUCTION MANUAL 6–55
Figure 6-25: Thermal Overload protection logic diagram
Operate #2 Trip
(TRIP W2 BKR)
Operate #1 Trip
(TRIP W1 BKR)
897815A1.cdr
TRIP (To Breaker Failure)
SETPOINTS
Phase A current (IA)
RUN
SETPOINT
FUNCTION Disabled = 0
Latched Alarm
PICKUP
AND
Phase B current (IB) Phase C current (IC)
LED: TRIP
Event Recorder
Transient Recorder
Alarm
OR
OR
Phase Currents
AND
Trip
AND
SETPOINT
BLOCK 1: Off = 0 BLOCK 2: Off = 0 BLOCK 3: Off = 0
OR
Message
THERMAL
OVERLOAD
Ph A Thermal OP Ph B Thermal OP
Ph C Thermal OP
OR
HEATING T . CONSTANT COOLING T. CONSTANT
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
ALARM
ALARM
θθ>
Ph B Thermal Alarm
Ph C Thermal Alarm
LED: ALARM
RESET
Command
AND
S R
LATCH
Event Recorder
Transient Recorder
SETPOINT
OUTPUT RELAY X
Do Not Operate, Operate