4000 Kva Oil-filled Transformer

The 4000 kVA Oil Immersed Transformer is specifically engineered as a Step-Up Unit for utility-scale photovoltaic (PV) power plants. Unlike standard distribution transformers that step down voltage, this unit functions in reverse, boosting the low voltage output from central inverters (typically 600V - 800V) up to medium voltage (33kV or 35kV) for grid transmission.

As a specialized solar transformer, it is designed to operate under the harsh, cyclic loading conditions of solar farms. It features a robust structural design capable of handling the "pulsed" nature of solar energy, where loads fluctuate rapidly with cloud cover, without suffering from thermal fatigue.

Efficiency in solar farm layout is key. A defining feature of our 4000 kVA model is the option for a Dual Low-Voltage (LV) winding configuration (e.g., Dy11y11 vector group).

• The Logic: This allows two separate 2.0 MW inverters to be connected to a single solar transformer.
• The Benefit: By galvanically isolating the two LV inputs, we minimize the circulating currents between inverters and significantly reduce the balance of system (BOS) costs by cutting down on trenching and cabling requirements.

Solar farms are often located in deserts or high-radiation zones.

• Outdoor Resilience: As a rugged oil filled transformer, the tank is coated with C4 or C5-High class UV-resistant paint to withstand decades of direct sunlight. The cooling system is oversized to function effectively even at ambient temperatures of 50°C.
• Night-Time Efficiency: Since solar plants generate zero revenue at night, "No-Load Loss" (Iron Loss) is a critical economic metric. We utilize high-permeability laser-scribed silicon steel to minimize core excitation power, ensuring the transformer doesn't drain profits during the night.

Close-up detail of stacked silicon steel core laminations showing

smooth edge finish.

• HV Connection: Typically fitted with an IP54 Cable Box suitable for terminating large cross-section XLPE cables coming from the MV switchgear.
• Internal Protection: Equipped with a Buchholz Relay and Pressure Relief Device (PRD) with trip contacts. In the event of an internal arc fault, these devices instantly isolate the transformer to prevent fire risks in remote solar fields.

• Utility-Scale Solar Parks: Connecting central inverters to the 33kV collector ring.
• Energy Storage Systems (BESS): Managing the bi-directional power flow for large battery containers (4MWh+) providing frequency regulation services.

4000 kVA oil immersed step-up transformer installed in a

utility-scale solar PV power plant.