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DIR 1000587R0002 (Version 02)
3.6.5.
Protection “G”
Protection G is provided by the trip unit via vectorial calculation of the neutral and phase currents. The fault current is defi ned
by the following formula:
In the case when the circuit does not show any fault, the module of the sum of these currents is always nil; vice versa the value
of the fault current will take on an increasingly large value depending on the size of the fault. This operating mode is enabled by
default.
The protection, which can be disabled, can be the fi xed time (t=k), or inverse time (t=k/I
2
)
The tripping time with inverse time curve is given by the expression: t(s)=
. If the calculated value is less than t
4
, the
real tripping time is forced to t
4
(t(s)= t
4
).
NOTES
:
- t(s):
estimated tripping time
-
I
f
:
fault current; given in [In] (example: 0.4In)
- I
4
, t
4
:
protection G parameters set by the user, given in [In] and [s]
ATTENTION: Protection G is disabled for current values of over 8In (for I
4
0.8In), over 6In (for 0.5In
I
4
<0.8In),
over 4In (for 0.2In
I
4
<0.5In) and over 2In (for I
4
<0.2In).
ATTENTION: In the absence of a separate supplied 24V DC voltage, the minimum threshold setting is 0.25In with
rating plug= 400A and 0.2In for all the other sizes. If the entered value fails to comply with this limitation, the SW
overrides the threshold until it reaches the minimum value accepted and “Confi guration” error appears on the
display.
ATTENTION: It is possible to disable the trip control of the protection (“Enable Trip: Off”).
In that case, for the whole duration of the unbalance the CB will not be opened, but only the condition will be
signaled by means of the “warning” LED lit up and a warning message.
3.6.5.1.
Start-up threshold “G”
The function behaves in exactly the same way as the protection “S”.
3.6.6.
Protection "U"
Protection against current unbalance with a fi xed time response (can be disabled).
The breaker trips when, for the
t6
time setting or longer, an unbalance is detected between two or more phases that is higher
than the
I6
threshold setting.
The percentage of current unbalance is calculated in the following way:
% Unbal =
100
max
min
max
.
−
I
I
I
where I
max
is the maximum and I
min
the minimum phase current.
The trip command of the protection can be disabled: in this case, CB opening is not controlled and the condition is merely sig-
nalled by leds and a message on the display.
ATTENTION: When the value of the phase current is above 6xIn, the function “U” excludes itself because, in this
case, the other protections intervene because the fault is considered as a phase fault.
The protection is not enabled for maximum phase current values lower than 0.3xIn.
3.6.7.
Protection "T"
A sensor inside the trip unit signals abnormal temperature conditions which could lead to temporary or continuous faults in the
electronic components of the unit.
This protection has two states of operation:
State of “WARNING TEMPERATURE” with
–25°C < temp. < -20°C
or
70°C < temp. < 85°C
:
the display is turned off and the “WARNING” LED fl ashes at 0.5Hz
State of “ALARM TEMPERATURE” with
temp.
–25°C
or
temp.
85°C
: the display is turned off, the “WARNING”
and “ALARM” Leds fl ash at 2Hz and the Trip is activated (if enabled by means of the “Over Temper. Trip = On” parameter).
In the event of Warning and Alarm, the display is turned off, to preserve its functionality;
The monitored temperature is not visible on the display.
The protection is always active, both with auxiliary supply and in self-supply.
ATTENTION: If the Trip command of the protection were to be disabled, the trip unit would operate, with the
circuit-breaker closed, within a temperature range where correct operation of the protections is not guaranteed.
