4 Protection settings
4.10 Zone selective interlocking (ZSI)
PXR Electronic trip unit
01/21 MN012005EN
www.eaton.com
31
The maintenance mode can be activated remotely via a normally open
contact (e.g. a door switch) that has been wired to the interface module of
the circuit breaker.
Figure 7:
ARMS wiring
The maintenance mode can also be activated through the communication
interface. This can either be done using a communication module or via the
configuration software and the USB port.
If the maintenance mode is activated using one of these methods, the
deactivation must also be carried out in the same way.
4.10 Zone selective interlocking (ZSI)
The ZSI function (ZSI = zone selective interlocking) can be activated or
deactivated either via the navigation menu, or via the Power Xpert Protection
Manager software and a communication link. The ZSI function can be used in
conjunction with the short-time protection functions and the ground-fault
protection. ZSI ensures that the circuit breaker trips as fast as possible in the
event of any faults within its zone of protection, while also enabling safe
coordination among all circuit breakers in the system (the main power
supply, nodes, feeders and any downstream circuit breakers).
If ZSI is enabled, a fault within the zone of protection will immediately trip the
circuit breaker and send a corresponding restraining signal to any upstream
trip units to prevent them from tripping instantly. This restraining signal will
cause all upstream circuit breakers to continue operating with their own
coordination delays, to ensure that the supply is only interrupted locally.
Figure 8:
ZSI circuits
ARMS In
ARMS GND
Z
out
Z
in
Z
com
Z
out
Z
in
Z
com
Z
out
Z
in
Z
com
