ABB Relion 650 Series Technical Manual page 262

Section 8
Frequency protection
Table 189: SAPTUF (81) Output signals
Name
TRIP
PICKUP
RESTORE
BLKDMAGN
8.1.5 Settings
Table 190: SAPTUF (81) Group settings (basic)
Name Values (Range)
Operation Disabled
Enabled
PUFrequency 35.00 - 75.00
tDelay 0.000 - 60.000
tRestore 0.000 - 60.000
RestoreFreq 45.00 - 65.00
8.1.6 Monitored data
Table 191: SAPTUF (81) Monitored data
Name
FREQ
8.1.7 Operation principle
Underfrequency protection (SAPTUF, 81) function is used to detect low power system frequency. If
the frequency remains below the set value for a time period corresponding to the chosen time
delay, the corresponding trip signal is issued. 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.
8.1.7.1 Measurement principle
The fundamental frequency of the measured input voltage is measured continuously, and
compared with the set value,
magnitude. If the voltage magnitude decreases the setting
preprocessing function, which is set as a percentage of a global base voltage parameter, SAPTUF
256
Type Description
BOOLEAN Common trip signal
BOOLEAN General pickup signal
BOOLEAN Restore signal for load restoring purposes
BOOLEAN Measurement blocked due to low voltage amplitude
Unit Step
- -
Hz 0.01
s 0.001
s 0.001
Hz 0.01
Type Values (Range)
REAL -
PUFrequency . The frequency function is dependent on the voltage
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Default Description
Disabled Disable/Enable Operation
48.80 Frequency set value
0.200 Operate time delay
0.000 Restore time delay
49.90 Restore frequency if frequency is above
frequency value
Unit Description
Hz Measured frequency
MinValFreqMeas in the SMAI
1MRK 506 326-UUS B
PID-1969-OUTPUTSIGNALS v6
PID-1969-SETTINGS v6
PID-1969-MONITOREDDATA v8
M13354-3 v4
M13354-6 v4
Line distance protection REL650
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