Three-phase oil-immersed power transformer

The oil-immersed three-phase transformer is a primary power transmission and distribution equipment widely used in power systems, industrial and mining enterprises, residential areas, commercial buildings, power plants, and other industries. It is mainly used to convert high-voltage electrical energy into low-voltage electrical energy that meets the needs of production, service life, and equipment operation, ensuring stable, efficient, and safe power supply. With strict production standards, advanced structural design, and reliable performance, it has become an indispensable key equipment in modern power grids.

1. General structure

The transformer has a compact and well-thought-out overall design. The foundation is a sealed oil tank made of high-quality cold-rolled steel plate. The tank body undergoes precision welding and shot blasting, followed by coating with a special paint that offers anti-corrosion, anti-rust, and anti-aging properties. This effectively protects the equipment from moisture, rain, dust, and harmful environmental gases, making it suitable for operation in harsh indoor and outdoor conditions. The scientific overall layout of the equipment, with clear functional zoning, not only facilitates daily inspection and maintenance but also enhances the operational stability of the transformer.

2. Main core

The magnetic core is made of high-quality cold-rolled grain-oriented electrical steel with high magnetic permeability and low losses. It is assembled using a multi-layer lamination method with tight clamping, which significantly reduces eddy current and hysteresis losses, improves the energy efficiency of the transformer, and reduces heat generation during operation. The surface of the magnetic core is coated with insulating enamel, enhancing insulation performance and preventing short circuits between steel sheets, ensuring safe and stable operation of the core.

3. Winding part

The windings are made of high-purity oxygen-free copper wire or copper foil, which possess excellent electrical and thermal conductivity, minimizing active losses in the windings. Modern winding technology is employed: turns are arranged evenly and tightly, ensuring high insulation reliability. Inter-turn and inter-phase insulation is made of heat-resistant, high-grade insulating paper and varnish, capable of withstanding high temperatures and stress loads, preventing inter-turn and inter-phase short circuits, and guaranteeing long-term stable operation of the windings. According to individual customer requirements, the windings can be designed in various modifications for different voltage classes and load capacities.

4. Insulating oil system

The transformer uses special transformer oil, which serves as an insulating and heat-dissipating medium. The oil has excellent insulating properties, a high flash point, low viscosity, and good thermal conductivity. It ensures reliable insulation of the magnetic core and windings, prevents electrical breakdown, and transfers the heat generated during transformer operation to the tank body for subsequent dissipation into the atmosphere. The tank is equipped with an oil conservator, which automatically compensates for changes in oil volume due to temperature fluctuations, prevents contact between the oil and air, reduces the oxidation rate, and extends the service life of the insulating oil. Additionally, the tank is equipped with an oil level indicator and a sampling valve, allowing regular monitoring of the oil level and laboratory analysis of the oil.

5. Protective components

The transformer is equipped with a full set of standard protective devices to ensure safe and reliable operation. An explosion-proof valve is installed, which automatically releases excess pressure in the event of an emergency pressure increase inside the tank (during short circuits and other faults), preventing tank rupture and ensuring the safety of personnel and equipment. A thermometric device (temperature sensor or thermometer) is mounted for continuous monitoring of the transformer oil temperature; when parameters exceed safe limits, a timely alarm signal is issued for prompt action. The configuration also includes a safety valve and a moisture absorber, which prevent moisture from entering the tank, preserve the insulating properties of the oil, and eliminate faults caused by dampness.

6. Technical Specifications

The transformer fully complies with international electrotechnical standards (IEC, ANSI) and national regulations, with stable operational performance. The rated voltage ranges from 10 kV to 35 kV, and the rated power ranges from 50 kVA to 2500 kVA. No-load and load losses are significantly lower than the requirements of national standards, ensuring energy savings and reduced operating costs. The equipment has high resistance to short-circuit currents, withstanding short-circuit current impacts without damage. The noise level does not exceed 65 dB, meeting environmental requirements for residential areas and commercial facilities. The high insulation class ensures resistance to overvoltages and safe operation of the equipment.

7. Installation and Maintenance

The transformer has a simple structure, light weight, and is convenient for transportation and installation. It can be installed on a concrete foundation or steel frame, and the installation process is simple and quick. The equipment design takes into account ease of maintenance, with free spaces provided for access to all parts and components. Daily maintenance includes checking the level, color, and temperature of the oil, noise level, periodic replacement of transformer oil and filter elements, and cleaning the external surface of the equipment. Low maintenance costs and a long overhaul period significantly reduce the customer's operating expenses in the long term.

8. Application areas

Due to their high performance and resistance to external conditions, oil-immersed three-phase power transformers are widely used in various industries. They are employed for power distribution in industrial and mining enterprises (factories, mines, production workshops), ensuring stable electricity supply for technological equipment; they operate in residential complexes and commercial buildings to convert high voltage to low voltage for domestic needs and commercial equipment; they are used in power plants and substations as part of power grids for electricity transmission and distribution, ensuring stable operation of the power system. The equipment adapts to various climatic conditions—high and low temperatures, high humidity, arid climates—and offers versatility in application.