The harmonics current I_HARM_RES is available in the monitored data view. The
value is also sent over horizontal communication to the other protection relays on
the parallel feeders configured in the protection scheme.
Normalized output
0.5
0
0
1.0
Frequency
2ff
Figure 236: 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.
Protection functions
1MRS757644 H
462 620 series
Technical Manual
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