4.6.2.6
Signals
Table 675: LSHDPFRQ Input signals
Name
Type
Default
Description
F
SIGNAL
0
Measured frequency
dF/dt
SIGNAL
0
Rate of change of fre-
quency
BLOCK
BOOLEAN
0=False
Block signal for acti-
vating the blocking
mode
BLK_REST
BOOLEAN
0=False
Block restore
MAN_RESTORE
BOOLEAN
0=False
Manual restore signal
Table 676: LSHDPFRQ Output signals
Name
Type
Description
OPERATE
BOOLEAN
Operation of load shedding
OPR_FRQ
BOOLEAN
Operate signal for under fre-
quency
OPR_FRG
BOOLEAN
Operate signal for high df/dt
START
BOOLEAN
Start
ST_FRQ
BOOLEAN
Pick-Up signal for under fre-
quency detection
ST_FRG
BOOLEAN
Pick-Up signal for high df/dt
detection
RESTORE
BOOLEAN
Restore signal for load re-
storing purposes
ST_REST
BOOLEAN
Restore frequency attained
and restore timer started
4.6.2.7
Settings
Table 677: LSHDPFRQ Group settings (Basic)
Parameter
Values (Range)
Unit
Step
Default
Description
Load shed mode
1=Freq<
6=Freq< OR df/dt
8=Freq< AND df/dt
1=Freq<
Set the operation
mode for load
shedding function
Restore mode
1=Disabled
2=Auto
3=Manual
1=Disabled
Mode of operation
of restore function-
ality
Start value Freq
0.800...1.200
xFn
0.001
0.975
Frequency set-
ting/start value
Start value df/dt
-0.200...-0.005
xFn /s
0.005
-0.010
Setting of frequen-
cy gradient for
df/dt detection
Table continues on the next page
Protection functions
1MRS757644 H
718
620 series
Technical Manual