An uninterruptible power supply sits between the grid and a critical load, using stored energy in batteries or flywheels to bridge power outages without a single cycle of interruption. It constantly conditions the incoming AC power, rectifying it to DC and inverting it back to clean AC. This guarantees that sensitive equipment like server racks or control room SCADA systems do not crash during a blackout or severe voltage sag.
The main breaker tripped but the servers stayed up because the uninterruptible power supply took the load instantly.
Also heard as
- UPS
Related terms
UPS
Uninterruptible power supply, a battery or flywheel system that instantly provides backup power during an outage.
Black start
Restarting a power system from total shutdown using generators that can start without any outside supply.
SCADA
Supervisory control and data acquisition: the system that lets a control room watch and switch remote plant.