REF or
Cable
end
Diff
0:REF
1:CED
-
REF
Selection of the operating characteristics. If selected REF the function operates with
normal accuracies and if CED is selected the natural unbalance created by the phase
current CT:s can be compensated for more sensitive operation. Default setting is REF.
Comp.
natural
unbal.
0:-
1:Comp -
-
When activated in on line the currently present calculated residual current will be
compensated to 0. This compensation does not have effect otherwise than in CED
mode.
Operating characteristics
Current dependent pick-up and activation of the REF function is controlled bysetting parameters, which
de nes the used current calculating method and operating characteristics.
Table. 5.4.10. - 107. Pick-up characteristics setting (SG selectable)
Name
Range
Step
Default
Description
I0 Input
0:I01
1:I02
-
I01
Selection of the used residual current measurement input. Default setting
is 0: I01
I0
Direction
0:Add
1:Subtract
-
Add
Differential current calculation mode. With this selection the directions of
the calculated and measured residual currents can be set to match the
application. Default setting is Add which means that I01 or I02 in
through fault yields 0 of differential current.
Bias
current
calc
0:(3Io+IoCalc)/2
1:max(3Io.I0calc) -
Residual
current
Selection of bias current calculation. Either maximum of all measured
currents or calculated residual current can be used for the differential
characteristics biasing. Residual current mode is more sensitive while
max current coarser. Default setting is Residual current.
I0d> pick
up
0.01…50.00%
(of In)
0.01%
10%
Setting for basic sensitivity of the differential characteristics.
Turnpoint
1
0.01…50.00xIn
0.01xIn 1.00xIn
Setting for rst turn point in the bias axe of the differential characteristics.
Slope 1
0.01…150.00%
0.01%
10.00%
Setting for the rst slope of the differential characteristics.
Turnpoint
1
0.01…50.00xIn
0.01xIn 3.00xIn
Setting for second turn point in the bias axe of the differential
characteristics.
Slope 2
0.01…250.00%
0.01%
40.00%
Setting for the second slope of the differential characteristics.
The pick-up activation of the function is not directly equal to trip-signal generation of the function. Trip
signal is allowed if blocking condition is not active.
In the following gure is presented the differential characteristics with default settings.
Figure. 5.4.10. - 63. Differential characteristics for REF function with default settings.
AQ-F255
Instruction manual
Version: 2.00
117
© Arcteq Relays Ltd