Specifications

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Doc. No
Model
Apparatus
Scale
Page No
1SDH000460R0002
L5439
% Unb =
100
max
minmax
.
−
I
II
where I
max
is the maximum and I
min
is the minimum phase current.
WARNING: 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.
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.
13.2.9.7. Protection against overtemperature inside the relay “OT”
There is a sensor inside the PR122/P unit that monitors the temperature of the unit.
This enables the signalling of any abnormal temperature conditions, which could cause temporary or continuous malfunctions
of the unit’s electronic components.
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 flashes at 0.5Hz
State of “ALARM TEMPERATURE” with
temp. < –25°C
or
temp. > 85°C
: the display is turned off, the “WARN-
ING” and “ALARM” Leds flash at 2Hz and the Trip is activated (if enabled by means of the “Over Temper. Trip = On” parameter).
N.B.:
 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.
WARNING: Disabling the Trip control of the protection means that the PR122/P unit could work, with the circuit-
breaker closed, in a range of temperatures where correct operation of the electronics is not guaranteed.
13.2.9.8. Load control function
Single loads can be enabled/disabled on the load side before the overload protection L intervenes and trips the circuit-breaker
on the supply side. This is done by contactors or switch-disconnectors (wired outside the release), controlled by the PR122/P by
means of contacts on the PR120/K module or on the PR021/K external unit.
The current thresholds are lower than those available with the protection L, so that the load control can be used to prevent trip-
ping due to overloads. The function is active when an auxiliary power supply is present, or supply from PR120/V (see par. 15.1.4).
The operating logic involves the activation of three contacts when the preset thresholds LC1, LC2 and I
w
are exceeded.
Thresholds LC1 and LC2 are expressed as a percentage of I
1
(current threshold specified for protection L) while the “warning
current” I
w
is expressed as an absolute value. The allowable values are given in the following table:
Threshold LC1 50%...100% x I1 step 1% I1
Threshold LC2 50%...100% x I1 step 1% I1
Threshold Iw 0,3 ...10,0 x In step 0,05 In
From the PR122/P you can associate each of the PR120/K or PR121/K contacts with a configuration (NO or NC), a delay and the
eventual latch.
13.2.9.9. Voltage protections “UV”, “OV”, “RV”, “U” (PROTECTIONS AVAILABLE ONLY WITH THE ADDITIONAL
PR120/V MODULE)
The PR122/P unit provides 4 voltage protections, which can be disabled, with fixed adjustable time (t = k), active both with self-
supply and with auxiliary supply:
- Undervoltage “UV”
- Overvoltage “OV”
- Residual voltage “RV”
- Line voltage unbalance “U”
Apart from normal timing and “Trip” operation, the voltage protections can be in a state defined as “alarm” (with the “emergency”
led on and an alarm message displayed) providing there is an auxiliary or PR120/V module power supply. In fact, in the case where
the circuit-breaker is open and no current is detected, the timing leads to the “alarm” state and not to “TRIP”. This is because the
fault linked to the voltages can persist even with the circuit-breaker open. When the circuit-breaker is closed or the passage of a
current is detected, you pass immediately from the state of “alarm” to “TRIP” without timing (see par. 13.3.2).
13.2.9.9.1 Protection “UV”
When the minimum phase voltage drops below the set threshold U
8
the protection counts down the preset time interval t
8
and
then opens.
13.2.9.9.2 Protection “OV”
When the maximum phase voltage exceeds the set threshold U
9
the protection counts down the preset time interval t
9
and then
opens.
13.2.9.9.3 Protection “RV”
When the residual voltage exceeds the set threshold U
10
the protection counts down the preset time interval t
10
and then opens.
The residual voltage U
0
is calculated by vectorially summing the phase voltages. It is therefore defined by the following formula.
3210
UUUU ++=