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4 irectional Protection "
The PR123/P unit carries out excludable directional protection against short-circuit with adjustable fixed time active both with self-powering
and with auxiliary supply.
This function enables better selectivity level obtained than using release without "double S".
14..
Wiring and enabling zone selectivity "S" alternative using protection "D" and operation only guaranteed when there auxiliary voltage.
The shield ust only earthed the circuit-breaker the supply-side relay (ZSI side).
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.
The following logical table implemented manage the Zone Selectivity Input (ZSI) and Zone Selectivity Output (ZSO) signals:
Z one tiv ity Imax ZSI ZSO signal rip T
Excluded trip
Excluded trip
Excluded YES programmed
Excluded YES programmed
Inserted trip
Inserted trip
Inserted YES tselectivity
Inserted YES programmed
The time must set value corresponding least tselectivity n50ms, supply side, not required the first one the chain. Mo..n remain operational.
1 S
Thanks the new PR123/P release that enables two independent and simultaneously active protection thresholds specified, selectivity
can assured even critical conditions.2.The zone selectivity function, guaranteed only auxiliary voltage provided, enables the area the fault isolated, only isolating the part
of plant nearest the fault, while keeping the rest the plant operational.
The ZSO output can connected maximum ZSI relays the supply side the selectivity chain. Especially
in ring distribution systems, this enables the distribution stretch where the fault occurred identified and isolated without interfering with
the rest the installation (using zone selectivity). 2
Page No.2).2.9.
The protection functionality very similar protection "S" with fixed time, with the capacity recognize the current direction during the fault
period well. the wiring has been done correctly, all the zone
selectivity inputs the last circuit-breakers the chain and all the outputs the circuit-breakers the head each chain must empty.2.
To determine the direction the current, the value the phase reactive powers has higher than the nominal phase power
(PQ> Pnphase '
The PR123 enables you define the power flow the circuit-breaker from the menu:
from high low (Top Bottom),
from low high (Bottom Top),
selectable the menu Modules Measuring Module (PR120/V).
This done connecting all the zone selectivity outputs the releases belonging the same zone one another (ZSO K51/SZout) and taking
this signal the zone selectivity input (ZSI K51/SZin) the next release the supply side. 11.9. This function valid for only.
A
The axim length cable for zone selectivity, between units, 300 meters.
14.2.
The direction the current enables the determination whether the fault the supply side the load side the circuit-breaker.3 Zone selectivity "S"
As practical example, the figure above shows fault the load side the "Relay 1a" isolated the latter without the "Relay the "Relay
0" being affected; fault immediately downstream from the "Relay will isolated the latter without the "Relay being affected, thus ensuring
that the Areas 2.
Use corded shielded o-w ire cable (see note par.
Model 2234 Apparatus Scale
L2778
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