Specifications

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Doc. no.
Model
Apparatus
Scale
Page No
1SDH000460R0002
L5439
14.2.9.2.2 Start-up threshold “S”
The start-up function can be selected in the case where the curve with fixed time is selected.
The start-up function can be selected in the case where the curve with fixed time is selected.
The function can be disabled and it is a setting characteristic of the single protection units.
The start-up function enables the protection threshold (S, D, I and G) to be changed during a time interval lasting “ts”, starting
from “start-up”. The latter must be intended as follows:
- Passage of at least one of the phase currents above the activation threshold of the adjustable Start-Up with SD TestBus2, Ekip
Connect or PR010/T (0.1…10In, by 0.1In steps); A new start-up is possible after the current has dropped below this threshold.
I
t
Start-Up Threshold I2
ts
Threshold I2
Activation of Start-Up
Threshold Start-Up activation
• Start-up time
The start-up time is common to all the protections involved.
Range: 0.1s ... 30s, with steps of 0.01s.
14.2.9.2.3 Zone selectivity“S”
The zone selectivity function, guaranteed only if an auxiliary voltage is provided, enables the area of the fault to be isolated, only
isolating the part of plant nearest to the fault, while keeping the rest of the plant operational.
This is done by connecting all the zone selectivity outputs of the releases belonging to the same zone to one another (ZSO=K51/
SZout) and taking this signal to the zone selectivity input (ZSI=K51/SZin) of the next release on the supply side. If the wiring has
been done correctly, all the zone selectivity inputs of the last circuit-breakers in the chain and all the outputs of the circuit-breakers
at the head of each chain must be empty.
Area 1
RELAY 1a
RELAY 1b
ZSO
ZSO
1a 1b
RELAY 1
ZSI
1
ZSO
1
Area 2
Area n
RELAY 2
ZSI
2
ZSO
2
RELAY 0
ZSI
0
RELAY n
ZSI
n
ZSO
n
As a practical example, the figure above shows a fault on the load side of the “Relay 1a” isolated by the latter without the “Relay
1” or the “Relay 0” being affected; a fault immediately downstream from the “Relay 1” will be isolated by the latter without the
“Relay 0” being affected, thus ensuring that the Areas 2...n remain operational.
The ZSO output can be connected to a maximum of 20 ZSI relays on the supply side in the selectivity chain.
WARNING: The maximum length of cable for zone selectivity, between two units, is 300 meters.
Use corded shielded two-wire cable (see note A to par. 11.2.2).
The shield must only be earthed on the circuit-breaker of the supply-side relay (ZSI side).
Wiring and enabling zone selectivity “S” is an alternative to using protection “D” and operation is only guaranteed when there is
an auxiliary voltage.
The following logical table is implemented to manage the Zone Selectivity Input (ZSI) and Zone Selectivity Output (ZSO) signals:
Zone selectivity I
f
> I
2
ZSI signal ZSO signal Trip T
Escluded NO 0 0 No trip
Escluded NO 1 0 No trip
Escluded YES 0 0 t
2
programmed
Escluded YES 1 0 t
2
programmed
Inserted NO 0 0 No trip
Inserted NO 1 1 No trip
Inserted YES 0 1 t
selectivity
Inserted YES 1 1 t
2
programmed
The time t
2
must be set at a value corresponding to at least t
selectivity
+50ms, on CB on supply side, not required on the first one
in the chain.