GE 339

CHAPTER 6: SETPOINTS S3 PROTECTION
339 MOTOR PROTECTION SYSTEM – INSTRUCTION MANUAL 6–113
Figure 6-47: Neutral Directional logic diagram
Zero Sequence Voltage (-V0)
SETPOINT
NTRL DIR FUNCTION: Disabled = 0
Latched Alarm
SETPOINTS
BLOCK 1: Off = 0 BLOCK 2: Off = 0 BLOCK 3: Off = 0
OR
NTRL DIR REVERSE
(To Neutral TOC and Neutral IOC )
Alarm
OR
OR
REVERSE
(Message)
AND
Control
Neutral Current (In) Ground current (Ig)
Voltage Polarization
-3V_0
3I_0
FWD
REV
REV
RUN
SETPOINT
NTRL DIR MTA
Current Polarization
REV
RUN
SETPOINT
NTRL DIR POLARIZING: Current
Dual Voltage
OR OR
SETPOINT
MIN POL VOLTAGE: |V0| >MINIMUM
AND
Ig > 0.05 x CT
AND
In > 0.05 x CT
AND
OR XOR
AND
NAND
AND
Ntrl Dir Reverse
(Event Recorder, Transient Recorder)
Direction OK
LED: ALARM
RESET
Command
AND
S R
LATCH
896017A3.cdr
OUTPUT RELAY X Do Not Operate, Operate
SETPOINT