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
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.
Table. 5.4.4 - 71. General settings of the function.
Name
Range
Default
Description
Setting control
from comm bus
1:
Disabled
2:
Allowed
1:
Disabled
Activating this parameter permits changing the pick-up level of the protection stage
via SCADA.
Measured
magnitude
1: RMS
2: TRMS
3: Peak-
to-peak
1: RMS
Defines which available measured magnitude is used by the function. This
parameter is available when "Input selection" has been set to "I01" or "I02".
Input selection
1: I01
2: I02
3:
I0Calc
1: I01
Defines which measured residual current is used by the function.
In the AQ-C215 relay the first (NEF1) and second (NEF2) instances of non-directional earth fault
function include the capacitor bank neutral unbalance protection functionality with natural unbalance
compensation. The following settings in the General settings are for the NEF1 and NEF2 instances, and
they control the function's behavior in the capacitor bank neutral unbalance protection application.
Table. 5.4.4 - 72. General settings for the function's NEF1 and NEF2 instances.
Name
Range
Default
Description
Functionality
0: Earth fault
protection
1: Capacitor
unbalance
0: Earth
fault
protection
Selects the functionality for the NEF1 and NEF2 stages in capacitor protection
relays.
Natural
unbalance
compensation
0: Not used
1: In use
0: Not
used
Selects whether the natural unbalance compensation is in use. When the
compensation is in use, you can give the function more sensitive settings. When
the compensation is not in use, the natural unbalance can cause the function to
operate either too sensitively or too coarsely (depends on which side of the
capacitor bank has more natural unbalance).
Compensat
natural
unbalance
0: -
1:
Compensate
0: -
Defines a triggering parameter which is activated during the function's
commissioning on the energized capacitor bank. The parameter is self-resetting
and it returns to "0: -" after user input and natural unbalance compensations are
made.
Pick-up
The
I0
set
setting parameter controls the the pick-up of the I0> function. This defines the maximum
allowed measured current before action from the function. The function constantly calculates the ratio
between the
I0
set
and the measured magnitude (
I
m
) for each of the three phases. The reset ratio of 97
% is built into the function and is always relative to the
I0
set
value. The setting value is common for all
measured phases. When the
I
m
exceeds the
I0
set
value (in single, dual or all phases) it triggers the
pick-up operation of the function.
A
AQ
Q-C215
-C215
Instruction manual
Version: 2.07
© Arcteq Relays Ltd
IM00040
119