13.2.9.2.3 Zone selectivity “S. Crate LS1-131

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, 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

Start-Up Threshold I2

Threshold I2

Threshold Start-Up activation

Activation of Start-Up ts time

The start-up time is common to all the protections involved.

Range: 0.1s … 30s, with steps of 0.01s.

t

13.2.9.2.3 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.

ZSO

1

RELAY 1

ZSI

1

RELAY 0

ZSI

0

ZSO

2

RELAY 2

ZSI

2

ZSO n

RELAY n

ZSI n

ZSO 1a

RELAY 1a

Area 1

RELAY 1b Area 2 Area 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.

Model

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).

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

Excluded

Excluded

Excluded

Excluded

Inserted

Inserted

Inserted

Inserted

I f

> I

2

NO

NO

YES

YES

NO

NO

YES

YES

ZSI signal

0

1

0

1

0

1

0

1

ZSO signal

0

0

0

0

0

1

1

1

Trip T

No trip

No trip t

2

programmed t

2

programmed

No trip

No trip t selectivity t

2

programmed

The time t

2

must be set at a value higher than or equal to t selectivity

+50 ms, on the CB on the supply side, not required on the first one in the chain.

“I”

The protection is enabled/disabled from the menu.

In the case where zone selectivity “S” is active, during the trip of the relay for “I”, the ZSO output signal is activated in any case

L2234

L2778

L4681

L5179

L5439

Apparatus Emax Scale

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