Eaton EDR-5000 Nstallation, Operation And Maintenance Manual page 585

EDR-5000 IM02602007E
Zone Coordination
General Description
What does Zone Coordination mean?
Zone Coordination means that the upstream protection device is doing a virtual autoreclosure while the downstream
protective device is doing a "real" autoreclosure. By means of the zone coordination, selectivity can be kept even if a
downstream protective device changes its tripping characteristic after a reclosure cycle. The virtual autoreclosure of
the upstream device follows the downstream autoreclosure.
What application can be realized by means of Zone Coordination?
A radial distribution system is protected by an upstream protective device (with a breaker) and a downstream protective
device with a reclosure and fuse. By means of the zone coordination, a "fuse saving scheme" might be realized. In
order to "save fuses", the downstream protective device might trip for the first reclosure attempt at low tripping values
(undergrade the fuse, trying to avoid a damaging of the fuse). If the reclosure attempt fails, the tripping values might be
raised (overgrade the fuse) for the second reclosure attempt (using higher tripping values/characteristics).
What is essential?
The triggering thresholds of the upstream and the downstream devices have to be the same but the tripping times have
to be selectively.
How is Zone Coordination activated?
The zone coordination function is part of the autoreclosure element and it can be enabled by setting the parameter
» Zone coordination« as » active« within the [Protection Para/AR/General Settings] menu for an upstream feeder
protection device.
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