UPS-generator backup chain failure

UPS-generator backup chain failure refers to a breakdown of the electrical backup system meant to absorb a grid outage without any service interruption: the UPS provides immediate continuity while generators start up, after which the generators take over for an extended period. A failure at any link, degraded UPS batteries, a faulty control module, a generator that fails to start or a poorly synchronized transfer, turns a grid outage that would normally be invisible into a complete systems shutdown. This risk is particularly insidious because the backup chain is rarely exercised under real conditions, with most tests run unloaded or only partially, so a latent defect can remain invisible for years before surfacing at the worst possible moment, during an actual grid outage. For insurers, this peril places the frequency and realism of switchover testing at the heart of risk assessment, with a site tested only through simulation being statistically more exposed than one subjected to regular full-load real-world tests.

In August 2016, the failure of an electrical control module at a Delta Air Lines data center in Atlanta prevented a proper switchover to backup generators, causing thousands of flight cancellations over several days at an estimated cost of roughly $150 million.

UPS failure, défaillance onduleur, backup generator failure, chaîne de secours électrique