Frequency Comparator
f < PuFrequency
Voltage
PICKUP
PICKUP
TRIP
Comparator
V < IntBlockLevel
BLOCK
Comparator
f > RestoreFreq
Block
OR
Time integrator
TimerOperation Mode 
Selector
TimeDlyOperate
TimeDlyReset
TimeDlyRestore
RESTORE
100 ms
Pickup
&
 Trip
Output 
Logic
en05000726_ansi.vsd
TRIP
BLKDMAGN
ANSI05000726 V1 EN
Figure 282: Simplified logic diagram for SAPTUF (81)
9.1.3  Function block
ANSI06000279-2-en.vsd
SAPTUF (81)
V3P*
BLOCK
BLKTRIP
BLKREST
TRIP
PICKUP
RESTORE
BLKDMAGN
FREQ
ANSI06000279 V2 EN
Figure 283: SAPTUF (81) function block
9.1.4  Input and output signals
Table 285: SAPTUF (81) Input signals
Name
Type Default Description
V3P GROUP
SIGNAL
- Voltage connection
BLOCK BOOLEAN 0 Block of function
BLKTRIP BOOLEAN 0 Blocking operate output.
BLKREST BOOLEAN 0 Blocking restore output.
1MRK505222-UUS C Section 9
Frequency protection
555
Technical reference manual