Figure. 5.3.11 - 128. Selectable measurement magnitudes with 2LL+U4 VT connection (P-E voltages not available without
residual voltage).
P-P Voltages and P-E Voltages selections follow phase-to-neutral or phase-to-phase voltages in the
first three voltage channels (or two first voltage channels in the 2LL+U3+U4 mode).
U4 input selection
follows the voltage in Channel 4.
U3Input selection only follows the voltage in Channel 3 if the
2LL+U3+U4 mode is in use.
Pick-up
The
U
set
setting parameter controls the pick-up of the U< function. This defines the minimum allowed
measured voltage before action from the function. The function constantly calculates the ratio
between the
U
set
and the measured magnitude (
U
m
) for each of the three voltages. The reset ratio of
103 % is built into the function and is always relative to the
U
set
value. The setting value is common for
all measured amplitudes, and when the
U
m
exceeds the
U
set
value (in single, dual or all voltages) it
triggers the pick-up operation of the function.
Table. 5.3.11 - 110. Pick-up settings.
Name
Description
Range
Step
Default
U
set
Pick-up setting
0.00…120.00%U
n
0.01%U
n
60%U
n
U Block
setting
Block setting. If set to zero, blocking is not in use. The operation is
explained in the next chapter.
0.00…100.00%U
n
0.01%U
n
10%U
n
The pick-up activation of the function is not directly equal to the START signal generation of the
function. The START signal is allowed if the blocking condition is not active.
Using
Block setting to prevent nuisance trips
It is recommended to use the
Block setting parameter to prevent the relay from tripping in a situation
where the network is de-energized. When the measured voltage drops below the set value, the relay
does not give a tripping signal. If the measured voltage has dropped below the
Block setting
parameter, the blocking continues until all of the line voltages have increased above the U< pick-up
setting. Please see the image below for a visualization of this function. If the block level is set to zero
(0), blocking is not in use.
A
AQ
Q-F205
-F205
Instruction manual
Version: 2.04
176
© Arcteq Relays Ltd
IM00013
Summary of Contents for AQ F205
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