Underfrequency Protection Saptuf (81) - ABB Relion Technical Manual

1MRK 502 048-UUS A
Section 10
10.1
10.1.1
10.1.2
10.1.3
Technical manual
Frequency protection

Underfrequency protection SAPTUF (81)

Identification
Function description
Underfrequency protection
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.
Function block
SAPTUF (81)
V3P* TRIP
BLOCK PICKUP
RESTORE
BLKDMAGN
ANSI09000282-1-en.vsd
ANSI09000282 V1 EN
Figure 148: SAPTUF (81) function block
Frequency protection
IEC 61850 IEC 60617
identification identification
SAPTUF
f <
SYMBOL-P V1 EN
Section 10
ANSI/IEEE C37.2
device number
81
319