ABB REC650 ANSI - Functionality; Identification; Underfrequency Protection SAPTUF (81)

Section 8 Frequency protection
8.1 Underfrequency protection SAPTUF (81)
8.1.1 Identification
Function description IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Underfrequency protection SAPTUF
f <
SYMBOL-P V1 EN
81
8.1.2 Functionality
Underfrequency occurs as a result of a lack of sufficient generation in the network.
Underfrequency protection SAPTUF (81) measures frequency with high accuracy, and is
used for load shedding systems, remedial action schemes, gas turbine startup and so on.
Separate definite time delays are provided for operate and restore.
SAPTUF (81) is provided with undervoltage blocking.
8.1.3 Function block
ANSI09000282-1-en.vsd
SAPTUF (81)
V3P*
BLOCK
TRIP
PICKUP
RESTORE
BLKDMAGN
ANSI09000282 V1 EN
Figure 78: SAPTUF (81) function block
1MRK 511 287-UUS A Section 8
Frequency protection
191
Technical manual