1250kVA 10kV Three-Phase Step-Down Oil-Immersed Power Distribution Transformer

Overview of the 1250kVA 10kV Oil-Immersed Transformer

The 1250kVA 10kV three-phase step-down oil-immersed power distribution transformer converts 10kV primary power to a lower distribution voltage for industrial, utility and commercial loads. Design and validation follow recognized calculation and verification procedures, and superior process equipment, careful material selection and efficient manufacturing give the unit a small volume, light weight, low loss, low partial discharge and low noise.

The product is stable, reliable, economical and environmentally friendly. Typical installation sites include power plants, transformer substations, large industrial mining enterprises and petrochemical plants.

Design Features

Low-Loss Core and Windings

The core is built from high-grade cold-rolled grain-oriented silicon steel, and the windings use quality conductors with an insulation structure that improves short-circuit resistance and service life. This combination keeps no-load and load losses low and reduces partial discharge.

Rugged Tank Construction

The oil tank is made of high-strength steel with excellent corrosion resistance and pressure resistance, ensuring durability in long-term service. Optional temperature protection and overload protection devices can isolate the circuit quickly when an abnormality occurs to prevent damage.

Cooling and Monitoring Options

Different cooling methods are available, including natural air cooling and forced air cooling, to suit different ambient temperature requirements. An adjustable temperature control device keeps operation stable under various working conditions, and an intelligent monitoring system can be configured to track operating status in real time and provide early warning information.

Specification Range (10kV-35kV Class)

The table lists representative values; the full 400-2500kVA range and customized combinations are available. Rated voltage combinations, connection symbols and loss targets can be adapted to the project and local grid standard.

Typical Applications

Power plants and transformer substations.

Large industrial and mining enterprises.

Petrochemical plants and refineries.

Commercial complexes and utility distribution networks.

Selection and Operation Notes

Confirm the primary voltage, secondary voltage, connection symbol, impedance and ambient conditions with the project specification. Where the load includes motors or converters, check harmonic content and consider additional filtering. For outdoor installations, specify the appropriate protection level and finish; for high ambient temperatures, review loading and cooling mode with the manufacturer. Routine maintenance covers oil level, temperature readings, bushing inspection and periodic oil testing.

Frequently Asked Questions

Q: What voltage combinations are available for this transformer?
The high-voltage side can be supplied for 10 kV, 11 kV, 20 kV or 35 kV classes, with a low-voltage side of 0.4 kV as standard. Other combinations can be customized to the local grid standard.

Q: What do Ydn11 and Yyn0 mean?
These are vector group symbols. Ydn11 indicates a star-connected high-voltage winding, a delta-connected low-voltage winding with a neutral brought out, and a 30-degree phase displacement; Yyn0 is a star-star connection with both neutrals, commonly used for three-phase four-wire distribution.

Q: Can the transformer be monitored remotely?
Yes. An intelligent monitoring system can be configured to track oil temperature, load and operating status in real time and provide early warning information for predictive maintenance.

Q: What cooling options are available?
Natural air cooling (ONAN) is standard; forced air cooling (ONAF) can be added to increase the continuous rating where ambient temperature or load profile requires it.

Q: What protection devices are available?
Optional temperature protection and overload protection devices can trip or alarm when the equipment is abnormal, preventing damage. Pressure relief devices and oil level gauges can also be fitted.

Q: Which standards apply to this transformer?
Design, testing and loss measurement follow IEC 60076 and GB/T 6451 for oil-immersed distribution transformers, with the applicable standard confirmed by the purchaser.