Figure. 5.4.8 - 45. Simplified function block diagram of the CBFP function.
Measured input
The function block uses analog current measurement values. It always uses the RMS magnitude of the
current measurement input. The user can select I01, I02 or the calculated I0 for the residual current
measurement. A -20 ms averaged value of the selected magnitude is used for pre-fault data
registering.
Table. 5.4.8 - 90. Measurement inputs of the CBFP function.
Signal
Description
Time base
IL1RMS
RMS measurement of phase L1 (A) current
5ms
IL2RMS
RMS measurement of phase L2 (B) current
5ms
IL3RMS
RMS measurement of phase L3 (C) current
5ms
I01RMS
RMS measurement of residual input I01
5ms
I02RMS
RMS measurement of residual input I02
5ms
I0Calc
Calculated residual current from the phase current inputs
5ms
DOIN
Monitors digital output relay status
5ms
DIIN
Monitors digital input status
5ms
The selection of the used AI channel is made with a setting parameter. In all possible input channel
variations the pre-fault condition is presented with a 20 ms averaged history value from -20 ms
from START or TRIP event.
General settings
The following general settings define the general behavior of the function. These settings are static i.e.
it is not possible to change them by editing the setting group.
A
AQ
Q-M257
-M257
Instruction manual
Version: 2.07
110
© Arcteq Relays Ltd
IM00021
Summary of Contents for AQ-M257
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