• differential characteristic comparator
• block signal check
• output processing.
The inputs for the function are the following:
• setting parameters
• measured and pre-processed current magnitudes.
The function's output signals can be used for direct I/O controlling and user logic programming. The
function generates general time-stamped ON/OFF events to the common event buffer from each of the
two (2) output signals. The time stamp resolution is 1 ms. The function also provides a
resettable cumulative counter for the REF, TRIP and BLOCKED events.
The following figure presents a simplified function block diagram of the restricted earth fault function.
Figure. 5.3.9 - 112. Simplified function block diagram of the I0d> function.
Measured input
The function block uses analog current measurement values. It uses the RMS magnitude of the current
measurement inputs. Both calculated residual currents and measured residual currents are always
used. The user can select inputs I01 or I02 for residual current measurement.
Please note that when the function is in cable end differential mode, the difference is only calculated
when the measured I0 current is available.
Table. 5.3.9 - 94. Measurement inputs of the I0d> 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
IL1Ang
Angle of phase L1 (A) current
5ms
IL2 Ang
Angle of phase L2 (B) current
5ms
A
AQ
Q-T215
-T215
Instruction manual
Version: 2.04
157
