STS

What does STS mean?

The Static Transfer Switch is an electronic transfer device that switches defined loads from the grid to the storage system during an outage — in under 20 ms on the OmniCube A215. Semiconductor switches make the transfer fast enough that controls, IT and many drives ride through with minimal interruption.

The distinction matters: an STS makes a storage system backup-capable, but it does not make it a UPS. A UPS bridges with zero interruption; the STS switches extremely fast. For most commercial loads that is sufficient — highly sensitive individual devices still need their own protection.

What matters in practice

• match the transfer time against the permissible interruption of the target loads
• grid disconnection and the protection concept are mandatory parts of STS planning
• inrush currents of the backup circuits limit the connectable load
• the switch-back on grid return must be defined

Practical example

The grid fails at a dairy farm. The STS transfers milking systems, refrigeration and controls to the storage system in under 20 ms — everything keeps running. Lighting and non-critical loads stay deliberately outside the backup circuit so the reserve lasts.

The Speichercampus perspective

Speichercampus always plans STS projects through a backup power concept: load list, power balance, inrush currents, bridging time. The fast transfer is a tool — the planning decides whether it holds.