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This protection has two states operation:
State "WARNING TEMPERATURE" with
and the "WARNING" LED flashes 0.
Zone selectivity "G" can active the same time zone selectivity "S".
The induced current the winding the toroid proportional the fault current which, this case, only transits the above-mentioned toroid.2. °C
temp. Trip On" parameter)
or
N.
In that case, for the hole duration the unbalance the ill not opened, but only the condition illbe signaled by
means the "warning" LED lit and arning essage.~ max min ~
It possible disable the trip control the protection ("Enable Trip: Off").
Disabling the Trip control the protection means that the PR122/P unit could ork, ith the circuit-breaker closed, range
o tem peratures here correct operation the electronics not guaranteed.
13.2.2 Zone selectivity "
The zone selectivity function can enabled providing the fixed time curve selected, and function assured only auxiliary voltage provided.
Model 2234 Apparatus Scale
L 2778
Doc No- 2
Page No.
P rotection with external "Source round eturn"
Also called "Source Ground return", this can carried out when there the need check operation machine (transformer, generator or
motor etc..2).2.9. Range: .
The protection not enabled for axim phase current values lower than 0.5Hz
State "ALARM TEMPERATURE" with
-2 temp. The minimum allowable threshold for the Gext protection 0.
W hen the value the phase current above 6xIn, the function "U" excludes itse because, case, the other protections
intervene because the fault considered phase fault.
To work this mode, "Ground protection" must selected the Circuit-breaker Settings menu.
1 rt-u "
The start-up function can selected the case where the curve with fixed time selected.2. temp.3). The fault current defined the following formula:
I N
In the case when the circuit does not show any fault, the module the sum these currents always nil; vice versa the value the fault current
will take increasingly large value depending the size thefault. 13.
The shield ust earthed both the circuit-breaker side and the toroid side.9.:
■ the event Warning and Alarm, the display turned off, preserve its functionality.
The PR122/P unit can provide two different types earth fault protection alternative:
It indispensable for the star center connected openly earth and for not used neutral conductor too (as the TNC system),
making protection according the system.2.
N.
The percentage unbalance therefore calculated %Unb= ------— 100 where the maximum and the minimum phase current. 11.2.B. This operating mode isenabled bydefault.
I .6 Protection against phase unbalance "
The protection with fixed time, which can excluded, trips the case when, for time greater than the same the time set, unbalance
is determined between two more phases higher than the set threshold I6.2.9.
This enables the signalling any abnormal temperature conditions, which could cause temporary continuous malfunctions the unit's electronic
components.2)
w ith length not exceeding 15m.
13.
A
The external toroid ust connected the PR122/P means corded shielded o-w ire cable (see note par.3xIn.
The behavior and wiring the function are identical those indicated for zone selectivity "S" (see par.B.
The protection always active, both with auxiliary supply and self-supply.
The protection assured physically positioning external toroid the cable connected from the star center the machine the earthing
connection point.) which has star-configured windings.ctio G
This provided inside the relay vectorially summing the phase and neutral currents. °C
: the display turned off
: the display turned off,
the "WARNING" and "ALARM" Leds flash 2Hz and the Trip activated (if enabled means the "Over Temper..
The function behaves exactly the same way the protection "S" (see par. 90% steps.
■ The monitored temperature not visible the display.9. -20 temp.1 (where the rated current
of the homopolar toroidal transformer; the settings available are 100, 250, 400, 800A).
The function can enabled and disabled the protection "G" page. 13.
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.5.: can used also with for external neutral.
1 tio rte "
There sensor inside the PR122/P unit that monitors the temperature the unit
