The function's outputs are START, TRIP and BLOCKED signals which 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 three (3) output signals. In the instant operating mode the
function outputs START and TRIP events simultaneously with an equivalent time stamp. The time stamp
resolution is 1 ms. The function also provides a cumulative counter for the START, TRIP and BLOCKED
events.
The following figure presents a simplified function block diagram of the neutral overvoltage function.
Figure. 5.3.12 - 81. Simplified function block diagram of the U0> function.
Measured input
The function block uses analog voltage measurement values. The function block uses RMS values. A
-20 ms averaged value of the selected magnitude is used for pre-fault data registering.
Table. 5.3.12 - 120. Measurement inputs of the U0> function.
Signal
Description
Time base
U0RMS
RMS measurement of voltage U0/V
5ms
U
L1
RMS
RMS measurement of voltage U
L1
/V
5ms
U
L2
RMS
RMS measurement of voltage U
L2
/V
5ms
U
L3
RMS
RMS measurement of voltage U
L3
/V
5ms
The selection of the AI channel currently in use 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 a 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-M255
-M255
Instruction manual
Version: 2.06
© Arcteq Relays Ltd
IM00020
147
Summary of Contents for AQ-M255
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