Transformer

What does transformer mean?

The transformer connects the voltage levels: it steps medium voltage (typically 10-30 kV) down to the site’s 400 V — or the storage voltage up. In larger projects it is a planning topic of its own, with lead time, cost and space requirements.

For storage projects the transformer matters twice: as a bottleneck when its rated power cannot carry additional charging or discharging power — and as a cost block when grid-scale systems like the PotisBank DC blocks need their own medium-voltage connection.

What matters in practice

• check transformer rating and current utilization before sizing the storage
• calculate simultaneity: storage charging must not overload the transformer
• for MWh projects, put transformer and switchgear costs into the budget early
• include medium-voltage transformer lead times in the project schedule

Practical example

An industrial site plans 500 kW of storage power on a 630 kVA transformer already 70 % loaded. The solution: limit charging power to low-load periods via the EMS — the storage fits without replacing the transformer.

The Speichercampus perspective

Speichercampus reviews the transformer situation in every larger project — it co-decides system size, charging logic and the boundary between C&I and grid-scale class.