ABB RED615 Technical Manual page 345

1YHT530004D05 D
615 series
Technical Manual
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Figure 175: High-pass filter
Level detector
The harmonics current is compared to the Start value setting. If the value exceeds
the value of the Start value setting, Level detector sends an enabling signal to the
Timer module.
Current comparison
The maximum of the harmonics currents reported by other parallel feeders in the
substation, that is, in the same busbar, is fed to the function through the
I_REF_RES input. If the locally measured harmonics current is higher than
I_REF_RES, the enabling signal is sent to Timer.
If the locally measured harmonics current is lower than I_REF_RES, the fault is
not in that feeder. The detected situation blocks Timer internally, and
simultaneously also the BLKD_I_REF output is activated.
The module also supervises the communication channel validity which is reported
to the Timer.
Timer
The START output is activated when Level detector sends the enabling signal.
Functionality and the time characteristics depend on the selected value of the
Enable reference use setting.
2f
Frequency
Section 4
Protection functions
339