What Is Inside a Containerized Box Transformer?

Many project buyers know box‑type transformers, yet few understand their internal layout.

To illustrate, we take a 1250kVA containerized box transformer for PV‑storage application as an example. It is a factory‑pre‑assembled 20‑foot container substation ready for on‑site installation.

Core Specifications

• Capacity: 1250kVA
• Transformer: SGB‑1250kVA / 0.8kV / 0.4kV, step‑up dry‑type
• Enclosure: Standard 20ft shipping container

Notably, this unit receives low‑voltage power from PCS, steps up voltage to 0.8kV for local loads or grid connection. The transformer supports bidirectional power flow within its rated parameters.

Internal Cabinet Layout (GGD switchgears inside container)

First of all, low‑voltage incoming cabinets collect power from multiple PCS units and provide circuit protection.

Next, the low‑voltage auxiliary power cabinet supplies power for cooling, lighting and control devices inside the container.

Furthermore, low‑voltage outgoing cabinets deliver transformed power to site loads, charging piles or the utility grid.

Besides, a separate compartment houses the transformer for better safety, heat dissipation and maintenance.

Last but not least, the SGB‑1250kVA transformer is the core component. It takes 0.4kV input from PCS and boosts voltage to 0.8kV.

Power Flow

To sum up, power flows as follows:

PV & battery → PCS → incoming cabinets → transformer (0.4kV→0.8kV) → outgoing cabinets → loads / grid.

On the other hand, it supports reverse operation: grid power flows backward to charge energy‑storage batteries.

Key Advantages for Overseas Projects

1. Factory pre‑assembly, cutting‑down on‑site installation work
2. 20ft container, easy sea‑freight transportation
3. Full‑set distribution & protection for PV‑storage sites

Need custom containerized box transformer for your PV‑storage project? We supply complete BOM, single‑line drawings and factory‑tested equipment. Contact us for your proposal.

Contact us – Distribution transformer,Oil immersed transformer,Dry type transformer-Unita Electric

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