SACE TMAX XT UL/CSA LOW VOLTAGE MOLDED CASE C I RCUI T- BRE AKERS UL4 89 AND CSA CS2 2 . 2 STANDARDS
6/8
— Adaptive Protections
Benefits Thanks to the Tmax XT it is possible to have two sets of settings implemented in a single device. As a result, the following benefits are guaranteed: • Overcurrent protection and selectivity 100% guaranteed both in grid-connected and islanded conditions. • Service continuity is garanted by just adding a single unit to the switchboard in every plant con- dition. • Ease of use, thanks to the Ekip Connect software which allows an immediate and intuitive commis- sioning phase.
With the adaptive protections, when there is an utility outage, circuit-breaker A opens and B closes in order to achieve an islanded condition. In order to still guarantee selectivity, another set of protec- tion settings is required. Adding Tmax XT adaptive protections to the circuit-breaker C1 ensures this behaviour. The second protection setting is opti- mized for the characteristics of the local generator ensuring the incoming supply. Additionally, selective coordination with the load side switching devices is also guaranteed. With reference to Fig. 1: • Circuit-breaker A is open • 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 • Molded case switch QS1 is closed • Non-priority loads can be disconnected using an- other 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 coordina- tion between circuit-breakers C and B by means of the Adaptive Protection function embedded in the trip unit of the C circuit-breakers.
10 3 s
10 3 s
B
A
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
— Fig. 2 - Protection thresholds during on-grid operation
— Fig. 3 - Protection thresholds during islanded operation
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