GE 339

CHAPTER 6: SETPOINTS S3 PROTECTION
339 MOTOR PROTECTION SYSTEM – INSTRUCTION MANUAL 6–59
Figure 6-25: Current Unbalance logic diagram
896823A1.cdr
SETTINGS
OUTPUT RELAY X
Do Not Operate, Operate
I
a
< Cuttoff Current
I
b
< Cuttoff Current
I
c
< Cuttoff Current
()
c
I
b
I
a
I
avg
I ++〈=
3
1
FLA
avg
I
factor
AFLA
avg
Iif
factor
AFLA
avg
Iif
=< =◊
,
1,
%100
1
2
Unbal 〈〈=
factor
A
I
I
RUN
UNBAL ALARM PKP
UNBAL = PICKUP
I
avg
= 0.25 x FLA
Unbal = 40%
OR
AND
OR
2s
0
SETTING
UNBAL ALARM FUNC:
Disabled=0
Enabled =1
OR
AND AND
LOGIC OPERANDS
UNBAL ALARM PKP
TARGET MESSAGE
UNBAL ALARM State Operate
ANY ALARM PKP
LATCH
S
R
OR
S3 CURRENT UNBAL
SETTING
UNBAL TRIP FUNC:
Disabled=0
Enabled =1
S3 CURRENT UNBAL
SETTING
BLOCK 1:
OFF = 0
S3 CURRENT UNBAL
BLOCK 2:
OFF = 0
BLOCK 3:
OFF = 0
OR
I
a
I
b
I
c
ACTUAL VALUES
  
  
++〈=
  
  
++〈=
c
aI
b
Ia
a
II
c
Ia
b
aI
a
II
2
3
1
2
2
3
1
1
SETTING
S3 CURRENT UNBAL
UNBAL ALARM DELAY
SETTING
S3 CURRENT UNBAL
t
PKP
0
UNBAL ALARM State Pickup
RUN
UNBAL TRIP CURVE
SETTING
S3 CURRENT UNBAL
UNBAL TRIP PKP UNBAL TRIP TDM UNBAL TRIP RESET TIME
Unbal = Pickup
UNBAL ALARM OP ANY ALARM OP
LOGIC OPERANDS
UNBAL TRIP PKP
TARGET MESSAGE
UNBAL TRIP State Operate
ANY TRIP PKP UNBAL TRIP State Pickup UNBAL TRIP OP ANY TRIP OP SINGLE PHASING OP
OR
SINGLE PHASEING TRIP State Operate
OR
SETTING
S4 CONTROL
Emergency Restart
OFF = 0
Lockout Reset
OFF = 0
Reset
OFF = 0
INPUTS
Emergency Restart Input
Lockout Reset Input
Reset Input
AND
KEYPAD RESET
AND
AND
LATCH
S
R
UNBAL TRIP MAX TIME UNBAL TRIP MIN TIME
t
I2/I1