Outage of the public power grid

Update timeline

1. identified Aug 09, 2026, 03:31 PM UTC

   We're currently monitoring a outage of the public power grid connection for TornadoDC FRA1. The datacenter has switched over to generator power supply and is supplied from there, UPSes took over the load until generator load transfer. We're investigating the issue.

2. resolved Aug 09, 2026, 03:49 PM UTC

   We had a defective fuse in the building NSHV. The same has been exchanged, the facility has switched back to regular grid supply.

3. postmortem Aug 11, 2026, 09:50 AM UTC

   The incident was caused by the failure of an NH fuse within the building’s main low-voltage switchboard \(NSHV\), specifically within the section supplying Tornado Datacenter. To mitigate the impact of such upstream power failures, Tornado Datacenter operates an automatic standby generator system that continuously monitors the quality and availability of the public grid supply. If grid parameters fall outside the defined operating limits, the generator starts automatically. Once generator voltage and frequency are stable and within specification, the datacenter’s electrical infrastructure automatically transfers the load to generator supply. The complete process takes approximately 20 seconds. During this transition period, the datacenter load is supplied without interruption by multiple UPS systems operating from battery power. The entire emergency power chain is tested every three months as part of scheduled black-building simulations. During these tests, the public grid supply to the datacenter is intentionally disconnected for approximately one hour to verify the operation of the UPS systems, automatic generator start, load transfer, sustained generator operation, and subsequent return to utility power. During the incident in question, the public grid supply to the datacenter became unavailable following the failure of the upstream NH fuse. As designed, the UPS systems immediately maintained power to the datacenter while the standby generator started and assumed the load. Qualified in-house electrical engineers subsequently identified and replaced the failed fuse. After the building supply had been restored and verified, the datacenter infrastructure automatically transferred back from generator operation to the public grid. The underlying cause was an increased electrical load associated primarily with higher cooling demand and the rapid growth of Tornado Datacenter. Several heatwaves during summer 2026, combined with the operation of the newly implemented chilled-water cooling system, resulted in significantly higher peak loads. Over a period of several months, repeated operation close to the fuse’s thermal limits led to progressive thermal ageing and ultimately caused the fuse to operate during a peak-load condition. As a long-term capacity expansion, we are currently planning the implementation of a new transformer substation, which is scheduled to become operational in the first quarter of 2027. This expansion will substantially increase the available electrical capacity and provide additional headroom for the continued growth of the datacenter, especially capacity in future Room B \(~1MW\).