Measured input
The function block uses analog current measurement values. The user can select the monitored
magnitude to be equal either to RMS values, to TRMS values, or to peak-to-peak values. TRMS mode
uses values from the whole harmonic spectrum of 32 components. Peak-to-peak mode picks
measurement values directly from the samples. A -20 ms averaged value of the selected magnitude is
used for pre-fault data registering.
The fault current angle is based on the comparison between the positive sequence voltage
U
1
and the
positive sequence current
I
1
. If the positive sequence voltage is not available (three line-to-line voltages
but no
U
0
), the voltage angle is based on a faulty phase line-to-line voltage. If the voltage drops below
1 V in the secondary side during a fault, the voltage memory is used for 0.5 seconds. After that the
reference angle of voltage is forced to 0°.
Table. 5.3.4 - 62. Measurement inputs of the Idir> 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
IL1TRMS
TRMS measurement of phase L1 (A) current
5ms
IL2TRMS
TRMS measurement of phase L2 (B) current
5ms
IL3TRMS
TRMS measurement of phase L3 (C) current
5ms
IL1PP
Peak-to-peak measurement of phase L1 (A) current
5ms
IL2PP
Peak-to-peak measurement of phase L2 (B) current
5ms
IL3PP
Peak-to-peak measurement of phase L3 (C) current
5ms
U
1
RMS
RMS measurement of voltage U
1
/V
5ms
U
2
RMS
RMS measurement of voltage U
2
/V
5ms
U
3
RMS
RMS measurement of voltage U
3
/V
5ms
U
4
RMS
RMS measurement of voltage U
4
/V
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.
Table. 5.3.4 - 63. General settings of the function.
Name
Description
Range
Step Default
Measured
magnitude
Defines which available measured magnitude is used by the
function.
1: RMS
2: TRMS
3: Peak-to-
peak
-
1: RMS
A
AQ
Q-F205
-F205
Instruction manual
Version: 2.04
© Arcteq Relays Ltd
IM00013
111
Summary of Contents for AQ F205
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