Signals; Settings; Monitored Data; Operation Principle - ABB REC650 Technical Manual

Section 8
Frequency protection
8.1.4
8.1.5
Table 137: SAPTUF Group settings (basic)
Name
Operation
StartFrequency
tDelay
tRestore
RestoreFreq
8.1.6
8.1.7
180

Signals

Table 135: SAPTUF Input signals
Name
U3P
BLOCK
Table 136: SAPTUF Output signals
Name
TRIP
START
RESTORE
BLKDMAGN

Settings

Values (Range) Unit
Off -
On
35.00 - 75.00 Hz
0.000 - 60.000 s
0.000 - 60.000 s
45.00 - 65.00 Hz

Monitored data

Table 138: SAPTUF Monitored data
Name
FREQ

Operation principle

The underfrequency protection (SAPTUF) function is used to detect low power
system frequency. If the frequency remains below the set value for a time period
greater than the set time delay the 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
Type Default Description
GROUP - Three phase group signal for voltage inputs
SIGNAL
BOOLEAN 0 Block of function
Type Description
BOOLEAN General trip signal
BOOLEAN General start signal
BOOLEAN Restore signal for load restoring purposes
BOOLEAN Measurement blocked due to low voltage
amplitude
Step Default
- Off
0.01 48.80
0.001 0.200
0.001 0.000
0.01 49.90
Type Values (Range)
REAL -
1MRK 511 287-UEN A
Description
Operation Off / On
Frequency set value
Operate time delay
Restore time delay
Restore frequency if frequency is above
frequency value
Unit Description
Hz Measured frequency
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