10.3.1
Identification
Function description
IEC 61850
identification
IEC 60617
identification
ANSI/IEEE C37.2
device number
Rate-of-change frequency protection
SAPFRC
df/dt
><
SYMBOL-N V1 EN
81
10.3.2
Functionality
The rate-of-change frequency protection function SAPFRC gives an early indication
of a main disturbance in the system. SAPFRC measures frequency with high
accuracy, and can be used for generation shedding, load shedding and remedial action
schemes. SAPFRC can discriminate between a positive or negative change of
frequency. A definite time delay is provided for operate.
SAPFRC is provided with an undervoltage blocking.
10.3.3
Function block
SAPFRC
U3P*
BLOCK
TRIP
START
RESTORE
BLKDMAGN
IEC09000281_1_en.vsd
IEC09000281 V1 EN
Figure 108:
SAPFRC function block
10.3.4
Signals
Table 164:
SAPFRC Input signals
Name
Type
Default
Description
U3P
GROUP
SIGNAL
-
Three phase group signal for voltage inputs
BLOCK
BOOLEAN
0
Block of function
Table 165:
SAPFRC Output signals
Name
Type
Description
TRIP
BOOLEAN
Operate/trip signal for frequency gradient
START
BOOLEAN
Start/pick-up signal for frequency gradient
RESTORE
BOOLEAN
Restore signal for load restoring purposes
BLKDMAGN
BOOLEAN
Blocking indication due to low amplitude
1MRK 504 135-UEN A
Section 10
Frequency protection
239
Technical manual
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