10.2.5 Settings
Table 311: SAPTOF Group settings (basic)
Name
Values (Range) Unit Step Default Description
Operation Off
On
- - Off Operation Off / On
StartFrequency 35.00 - 90.00 Hz 0.01 51.20 Frequency set value
tDelay 0.000 - 60.000 s 0.001 0.000 Operate time delay
tReset 0.000 - 60.000 s 0.001 0.000 Time delay for reset
Table 312: SAPTOF Non group settings (basic)
Name Values (Range) Unit Step Default Description
GlobalBaseSel 1 - 12 - 1 1 Selection of one of the Global Base Value
groups
10.2.6 Monitored data
Table 313: SAPTOF Monitored data
Name
Type Values (Range) Unit Description
ULevel REAL - kV Level of measured
voltage
FREQ REAL - Hz Measured frequency
10.2.7 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 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.
10.2.7.1 Measurement principle
The fundamental frequency of the positive sequence voltage is measured
continuously, and compared with the set value, StartFrequency. Overfrequency
protection SAPTOF is dependent on the voltage magnitude. 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 percent of the UBase, which
Section 10 1MRK502052-UEN B
Frequency protection
550
Technical manual
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