Page 142 - SACE Tmax XT - Catalogue

6/8 SACE TMAX XT LOW VOLTAGE MOLDED CASE CIRCUIT-BREAKERS

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Adaptive Protections

With the adaptive protections, when there is an Benefits
utility outage, circuit-breaker A opens and B closes Thanks to the Tmax XT it is possible to have two
in order to achieve an islanded condition. In order sets of settings implemented in a single device.
to still guarantee selectivity, another set of As a result, the following benefits are guaranteed:
protection settings is required. Adding Tmax XT • Overcurrent protection and selectivity 100%
adaptive protections to the circuit-breaker C1 en- guaranteed both in grid-connected and is-
sure this behaviour. The second protection set- landed conditions.
ting is optimized for the characteristics of the lo- • Service continuity is garanted by just adding a
cal generator ensuring the incoming supply. single unit to the switchboard in every plant
Additionally, selective coordination with the load condition.
side switching devices is also guaranteed. • Ease of use, thanks to the Ekip Connect soft-
With reference to Fig. 1: ware which allows an immediate and intuitive
• Circuit-breaker A is open commissioning phase.
• Circuit-breaker B is closed
• Circuit-breakers at position C are closed and the
protection thresholds move automatically to
“Set B”
• Circuit-breakers at position D are closed
• Circuit-breaker E is open
• Switch-disconnector QS1 is closed
• Non-priority loads can be disconnected using
another functionality of the Tmax XT units (see
next paragraph).

Fig. 3 shows how it is possible to switch to a set
of parameters which guarantees selective coordi-
nation between circuit-breakers C and B by
means of the Adaptive Protection function em-
bedded in the trip unit of the C circuit-breakers.

10 3 s 10 3 s
A B
10 2 s 10 2 s
10s 10s
C C
D D
1s 1s
10 -1 s 10 -1 s
10 -2 s 10 -2 s
10 -3 s 10 -3 s 10 2 kA 10 3 kA
1kA 10kA 10 2 kA 10 3 kA 1kA 10kA
Time-Current curves Time-Current curves
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Fig. 2 - Protection thresholds during on-grid operation Fig. 3 - Protection thresholds during islanded operation