Settings - ABB REG650 Technical Manual

Section 10
Frequency protection
10.3.5
Table 179: SAPFRC (81) Group settings (basic)
Name Values (Range)
Operation Disabled
Enabled
PUFreqGrad -10.00 - 10.00
tTrip 0.000 - 60.000
RestoreFreq 45.00 - 65.00
tRestore 0.000 - 60.000
10.3.6
10.3.6.1
300
Table 178: SAPFRC (81) Output signals
Name Type
TRIP BOOLEAN
PICKUP BOOLEAN
RESTORE BOOLEAN
BLKDMAGN BOOLEAN

Settings

Unit Step
- -
Hz/s 0.01
s 0.001
Hz 0.01
s 0.001
Operation principle
Rate-of-change frequency protection SAPFRC (81) is used to detect fast power system
frequency changes, increase as well as, decrease at an early stage. SAPFRC (81) has a
settable definite time delay.To avoid an unwanted trip due to uncertain frequency
measurement at low voltage magnitude, a voltage controlled blocking of the function is
available from the preprocessing function that is, if the voltage is lower than the set
blocking voltage in the preprocessing function, the function is blocked and no PICKUP
or TRIP signal is issued. If the frequency recovers, after a frequency decrease, a restore
signal is issued.
Measurement principle
The rate-of-change of the fundamental frequency of the selected voltage is measured
continuously, and compared with the set value, PUFreqGrad. If the voltage magnitude
decreases below the setting MinValFreqMeas in the preprocessing function, which is
set as a percentage of a global base voltage parameter, SAPFRC (81) is blocked, and
the output BLKDMAGN is issued. The sign of the setting PUFreqGrad, controls if
SAPFRC (81) reacts on a positive or on a negative change in frequency. If SAPFRC (81)
is used for decreasing frequency that is, the setting PUFreqGrad has been given a
Description
Operate/trip signal for frequency gradient
Start/pick-up signal for frequency gradient
Restore signal for load restoring purposes
Blocking indication due to low magnitude
Default Description
Disabled Disable/Enable Operation
0.50 Frequency gradient pick up value, the sign
defines direction
0.200 Operate time delay in positive / negative
frequency gradient mode
49.90 Restore is enabled if frequency is above set
frequency value
0.000 Restore time delay
1MRK 502 043-UUS B
Technical Manual