STS
STS in the SpeicherCampus context: a fast transfer device for backup power or island mode. Technically, the term is usually described as Static Transfer Switch.
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.