Battery storage imposes truly bidirectional flow and harmonic-rich converters: the transformer is specified for that duty from the start, not patched afterwards.
A conventional distribution transformer is designed for downward flow and a roughly sinusoidal load. A battery system charges and discharges, the flow reverses several times a day, and the PCS converters inject harmonics that heat the windings beyond the apparent RMS current. The engineering answer: a K-adapted design (thermal oversizing of the windings), screens and vector group chosen for inverter duty, and endurance against repeated thermal cycling.
Tell us in your request: PCS rating and number of units, harmonic spectrum (THDi), cycling profile (cycles/day), dedicated or shared transformer, site constraints (outdoor, coastal, altitude).
| Parameter | Typical BESS range |
|---|---|
| Power | 630 – 3,150 kVA per conversion unit |
| Impedance | 6 – 8 % depending on PCS requirement |
| K-factor | K4 – K13 depending on harmonic spectrum |
| Vector group | Dyn11 (others per conversion scheme) |
| Dielectric | mineral oil · ester (enhanced fire safety) · cast resin |
| Delivered lead time | 15 to 18 weeks, production + shipping |
Indicative pre-sizing values, the final specification follows your requirement and the actual PCS duty, confirmed at quotation.
Technically it will run, but it ages prematurely: converter harmonics create additional losses its thermal design never accounted for. A K-adapted design costs little at the design stage and avoids an early replacement.
Both architectures exist: one transformer per conversion unit, or a shared multi-winding unit. The choice follows the project's electrical scheme, tell us yours and we will quote both if useful.
No, but it is often chosen: high fire point and biodegradability strengthen the fire-safety case for a storage site. Mineral oil, ester or cast resin, we quote against your risk analysis.
Select “Storage / BESS” in the Application field of the configurator, or send your specification, first reply within 48 h.
Configure a quote →