Settings; Monitored Data; Operation Principle; Measurement Principle - ABB REG650 Technical Manual

Section 9
Frequency protection
9.1.5
Table 158: SAPTUF Group settings (basic)
Name
Operation
StartFrequency
tDelay
tRestore
RestoreFreq
9.1.6
9.1.7
9.1.7.1
256
Table 157: 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 159: SAPTUF Monitored data
Name
FREQ

Operation principle

Underfrequency protection (SAPTUF) 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 START or TRIP
signal is issued.

Measurement principle

The fundamental frequency of the measured input voltage is measured
continuously, and compared with the set value, StartFrequency. The frequency
function is dependent on the voltage magnitude. If the voltage magnitude decreases
the setting MinValFreqMeas in the SMAI preprocessing function, which is set as a
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 502 034-UEN -
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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