Application Guide - NP900 Series
101 (504
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A996A
Figure 3.2.8-47 Simplified function block diagram of the HOC function.
3.2.8.1
M
EASURED INPUT VALUES
Function block uses analog current measurement values from the phase currents or
residual currents. For each measurement input the HOC function block utilizes the
fundamental frequency and harmonic components of the selected current input and by
user selection the monitored magnitude can be either per unit RMS values of the
harmonic component or harmonic component percentage content compared to
fundamental frequency RMS. -20ms averaged value of the selected magnitude is used for
pre-fault data registering.
