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

Section 8
Frequency protection
8.2.5
Table 142: SAPTOF Group settings (basic)
Name
Operation
StartFrequency
tDelay
8.2.6
8.2.7
8.2.7.1
184
Table 141: SAPTOF Output signals
Name
TRIP
START
BLKDMAGN

Settings

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

Monitored data

Table 143: SAPTOF Monitored data
Name
FREQ

Operation principle

Overfrequency protection SAPTOF is used to detect high power system frequency.
SAPTOF has a settable definite time delay. If the frequency remains above 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 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 frequency measuring element continuously measures the frequency of the
positive sequence voltage and compares it to the setting StartFrequency. The
frequency signal is filtered to avoid transients due to switchings and faults in the
power system. If the voltage magnitude decreases below the setting MinValFreqMeas
in the SMAI preprocessing function, which is discussed in the Basic IED Functions
chapter and is set as a percentage of a global base voltage parameter UBase, SAPTOF
is blocked and the output BLKDMAGN is issued. All voltage settings are made in
Type Description
BOOLEAN General trip signal
BOOLEAN General start signal
BOOLEAN Measurement blocked due to low amplitude
Step Default
- Off
0.01 51.20
0.001 0.200
Type Values (Range)
REAL -
1MRK 511 287-UEN A
Description
Operation Off / On
Frequency set value
Operate time delay
Unit Description
Hz Measured frequency
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