What Is Selective Coordination?_
The goal is to limit outage scope to the smallest possible segment of the distribution system. Devices are chosen and set so their operating times and current thresholds create a clear hierarchy from branch to main. This requires review of time-current curves for each breaker or fuse in the chain.
Technical Details
Coordination studies compare the published curves of series devices to confirm that the downstream unit clears the fault before the upstream unit begins to unlatch. The study accounts for available short-circuit current at each point and any motor or capacitive inrush that could affect trip timing. Results are documented on a one-line diagram with the final settings applied to adjustable breakers or noted for non-adjustable units.
How Leviathan Systems Works with Selective Coordination
During rack-level power-up of H100 or GB200 NVL72 systems the PDU branch breakers must coordinate with row-level distribution so a single rack fault does not de-energize neighboring racks.
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GPU Rack Assembly & Rack-and-Stack →