CHAPTER 8: CONTROL
UNDERFREQUENCY RESTORATION
850 FEEDER PROTECTION SYSTEM – INSTRUCTION MANUAL
8–55
Figure 8-25: Underfrequency Restoration logic diagram
FASTPATH:
Upon voltage and frequency recovery (measured frequency above programmed
minimum), and “Close” output relay selected as Self-Reset type, the UF Restore operating
condition and hence the Close output relay will reset automatically after the breaker is
detected closed. If the “Close” output relay is selected as Pulsed type, the output relay will
stay closed, until the programmed Seal-In time expires.
894070A3.cdr
LED: PICKUP
SETPOINTS
BLOCK:
Of
f=0
AND
SETPOINTS
UF REST
ORE
FUNCTION:
Disabled
Alarm
Latched
Alarm
Configurable
OR
The V
oltage Input is the same as the one used for UF
or Freq.
ROC element selected under the setpoint
“UF
Restore initiation”
None
AND
SETPOINTS
UF REST
ORE
MINIMUM FREQUENCY
:
f
MINIMUM
FREQUENCY
f
RUN
SETPOINTS
UF REST
ORE
REST
ORE DELA
Y
:
t
RSR
0
UF Restore OP
FlexLogic Operands
UF Restore PKP
AND
AND
Command
RESET
OR
LED:
ALARM
WYE
DEL
T
A
VA
VA
B
VB
VBC
VC
VCA
OR
AND
Command
RESET
SETPOINTS
UF REST
ORE
INCOMPLETE
SEQUENCE
TIME:
t
IST
0
Status Input
to BKR1 Close Relay
Select output relay
Vx
Positive
-
sequence,
Composite or
Auxiliary V
oltage
SETPOINTS
UF REST
ORE
MINIMUM VOL
T
AGE:
V
MINIMUM
RUN
S
LA
TCH
Set
-
Dominant
R
SETPOINTS
UF REST
ORE
INITIA
TION:
Off = 0,
Underfreq 1 OP
,«
Underfreq 6 OP
,
Freq Rate 1 DWN OP
,«
Freq Rate 6
DWN OP
Close
AND
SETPOINTS
OUTPUT
RELA
YS (3
-7):
Do Not Operate, Operate
UF Restore Init
AND
from BKR1 Status
FlexLogic Operand
BKR 1 Closed
FlexLogic Operand
BKR 1 Closed
BKR 1 Open
BKR 1 Open
SETPOINT
SYNCHROCHECK
SUPER
VISION:
Bypass
Sync1 Close Perm
Sync1 Close Perm
From Synchrocheck 1
AND
AND
OR
Sync2 Close Perm
From Synchrocheck 2
AND
AND
Sync2 Close Perm
Summary of Contents for Multilin 850
Page 10: ...VIII 850 FEEDER PROTECTION SYSTEM INSTRUCTION MANUAL ...
Page 135: ...CHAPTER 3 INTERFACES SOFTWARE INTERFACE 850 FEEDER PROTECTION SYSTEM INSTRUCTION MANUAL 3 41 ...
Page 151: ...CHAPTER 3 INTERFACES SOFTWARE INTERFACE 850 FEEDER PROTECTION SYSTEM INSTRUCTION MANUAL 3 57 ...
Page 153: ...CHAPTER 3 INTERFACES SOFTWARE INTERFACE 850 FEEDER PROTECTION SYSTEM INSTRUCTION MANUAL 3 59 ...
Page 439: ...CHAPTER 7 MONITORING FUNCTIONS 850 FEEDER PROTECTION SYSTEM INSTRUCTION MANUAL 7 19 ...
Page 644: ...11 20 850 FEEDER PROTECTION SYSTEM INSTRUCTION MANUAL FLEXELEMENTS CHAPTER 11 METERING ...