Three-phase oil-immersed electric power transformer

An oil-immersed three-phase transformer is essential power transmission and distribution equipment, widely used in power grids, industrial and mining facilities, residential areas, commercial buildings, power plants, and other industries. It is primarily used to convert high-voltage electricity to low-voltage power, meeting the needs of production, equipment lifespan, and operation, ensuring a stable, efficient, and safe power supply. Thanks to strict manufacturing standards, modern structural design, and reliable performance, it has become an indispensable key component in the modern power grid.

1. General design

The transformer has a compact and well-thought-out overall design. Its core is a sealed oil tank made of high-quality cold-rolled steel plate. The tank body undergoes precision welding and shot blasting, followed by a special paint coating with 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 use in harsh indoor and outdoor conditions. The intelligent overall layout of the equipment, with its clearly separated functional zones, not only simplifies daily inspection and maintenance but also improves the transformer's operational stability.

2. Main core

The magnetic core is made of high-quality cold-rolled oriented electrical steel with high magnetic permeability and low losses. It is assembled using a multilayer stacking method with tight clamping, which significantly reduces eddy and hysteresis losses, improves the transformer's energy efficiency, and reduces heat generation during operation. The magnetic core surface is coated with insulating enamel, which improves insulation properties and prevents short circuits between the steel sheets, ensuring safe and stable core operation.

3. Winding part

The windings are made of high-purity oxygen-free copper wire or copper foil, which have excellent electrical and thermal conductivity, minimizing active losses in the windings. Modern winding technology is used: the turns are laid evenly and tightly, ensuring high insulation reliability. Interturn and interphase insulation is made of heat-resistant, high-grade insulating paper and varnish, which withstand high temperatures and intense loads, prevent interturn and interphase short circuits, and guarantee long-term stable operation of the windings. Windings can be designed in various modifications to suit individual customer requirements, suiting different voltage classes and load capacities.

4. Insulating oil system

The transformer uses a special transformer oil that serves as an insulating and heat-dissipating medium. This oil features excellent insulating properties, a high flash point, low viscosity, and good thermal conductivity. It provides reliable insulation for the magnetic core and windings, prevents electrical breakdown, and conducts heat generated during transformer operation to the tank body for subsequent dissipation into the atmosphere. The tank is equipped with an oil expansion chamber, which automatically compensates for oil volume changes due to temperature fluctuations, prevents oil exposure to air, reduces oxidation, and extends the life of the insulating oil. Furthermore, the tank is equipped with an oil level indicator and a sampling valve, allowing for regular oil level monitoring and laboratory analysis.

5. Protective elements

The transformer is equipped with a full set of standard safety devices to ensure safe and reliable operation. An explosion-proof valve automatically relieves excess pressure in the event of an emergency pressure increase within the tank (due to short circuits or other faults), preventing rupture and ensuring the safety of personnel and equipment. A temperature sensor or thermometer is installed to continuously monitor the transformer oil temperature; if the temperature exceeds safe limits, a timely alarm is generated for prompt action. A safety valve and desiccant are also included, preventing moisture from entering the tank, preserving the insulating properties of the oil, and preventing malfunctions due to moisture.

6. Technical specifications

The transformer fully complies with international electrical standards (IEC, ANSI) and national regulations, delivering stable performance. Nominal voltage ranges from 10 kV to 35 kV, and rated power ranges from 50 kVA to 2500 kVA. No-load and load losses are significantly lower than national standard requirements, ensuring energy savings and reduced operating costs. The equipment is highly resistant to short-circuit currents and can withstand short-circuit currents without damage. Noise levels do not exceed 65 dB, meeting environmental requirements for residential and commercial environments. A high-grade insulation ensures overvoltage resistance and safe operation.

7. Installation and maintenance

The transformer has a simple design, is lightweight, and is easy to transport and install. Installation can be carried out on a concrete foundation or steel frame, and the process is simple and quick. The equipment is designed for ease of maintenance, with clear spaces provided for access to all units and components. Daily maintenance includes monitoring the oil level, color, and temperature, as well as noise levels, periodic replacement of transformer oil and filter elements, and cleaning of the equipment's exterior. Low maintenance costs and a long period between repairs significantly reduce the customer's operating costs in the long term.

8. Areas of application

Thanks to their high performance characteristics and resistance to external conditions, oil-immersed three-phase power transformers are widely used in various industries. They are used for power distribution in industrial and mining facilities (factories, mines, production facilities), ensuring a stable power supply to process equipment. They are also used in residential complexes and commercial buildings to convert high voltage to low voltage for household needs and the operation of commercial equipment. They are also used in power plants and substations within power grids for the transmission and distribution of electricity, ensuring the stable operation of the power system. This equipment adapts to various climatic conditions – high and low temperatures, high humidity, and arid climates – and offers versatility.