In the realm of electrical engineering, transformers play a pivotal role in the transmission and distribution of electrical power. Among the various types of transformers, oil immersed transformers stand out due to their efficiency and reliability. These transformers are widely used in power grids, industrial settings, and commercial applications. In this post, we will delve into the fundamentals of oil immersed transformers, examining their construction, operation, benefits, and the crucial role they play in ensuring stable and efficient power distribution across different sectors. Whether you are an industry professional or simply curious about electrical systems, this comprehensive guide will provide valuable insights into the world of oil immersed transformers.

What is Oil Immersed Transformers?

There are two main types of transformers based on cooling: oil filled and dry. Oil immersed transformers use insulating oil inside a sealed steel tank to keep themselves cool. This oil absorbs heat from the transformer's core and coils, and then transfers it to the environment. Depending on the size of the transformer, it might rely on natural air circulation or fans to cool the oil.

To avoid deterioration, transformer oil must be kept at operating temperature that is less than 85°C. The daily temperature should be around 30°C in order for the transformers to run efficiently and prevent excessive oil deterioration. 

Structure and Operations of Oil Immersed Transformers

 

An oil filled transformer shares a similar structure to that of a standard transformer. Classified based on core insulation type, it is distinguished by its oil-immersed coils, which help reduce the internal heat. 

 

The essential components of an oil-immersed transformer include the magnetic core, windings, and bushings. The magnetic core provides a path for the magnetic flux. The windings, composed of conductor coils wrapped around the core, generate a magnetic field and are insulated with pressboard barriers and screens, with insulation thickness increasing with voltage. Bushings serve to connect the transformer windings to a substation.

 

Oil-filled transformers are commonly used in power distribution or electrical substations. Their core and coils are submerged in oil, which serves both to cool and insulate. The oil circulates through ducts in and around the coils and core assembly by convection. In smaller units, the oil is cooled by the tank's exterior, while in larger units, cooling is facilitated by an air-cooled radiator.

 

Types of Oil Immersed Transformers

 

The oil immersed transformers have two main types, such as one phase transformers and three phase transformers. 

 

1. One phase oil filled transformer

Single-phase oil-filled transformers efficiently adjust voltage for homes and businesses. They use a steel tank filled with insulating oil to cool the device and prevent electrical issues. By applying AC (alternative current) current, they step up or step down voltage based on their design. These transformers are common for power distribution, lighting, and specific equipment. While efficient and durable, they require maintenance and have environmental concerns due to the oil.

 

2. Three phase oil filled transformer

Three phase oil filled transformers are used for high power applications in industrial and commercial settings. They work similarly to single phase models, using oil for cooling and insulation, but with three sets of windings to handle three-phase power. This allows them to transform much larger amounts of voltage. Due to their size, they often require additional forced air cooling for better heat dissipation. Like single-phase transformers, they require maintenance and have environmental considerations due to the oil.

 

3. Power transformers

This type of transformers are designed to handle higher loads. They can step up and down voltages and transmit a current from one place to another.

 

4. Pole mounted transformers

This type of transformer is connected to an electrical pole. 

 

5. Pad mounted transformers 

This type of transformers are mounted to a concrete pad on the ground. 

Advantages of Oil Immersed Transformers

 

Contractors often need to decide between oil-filled and dry-type transformers, both of which offer distinct advantages. Here are some reasons why an oil-filled transformer might be the right choice.

 

Firstly, oil-filled transformers are more cost-effective, often costing up to half the price of a dry-type transformer with the same capacity.

 

Secondly, oil-immersed transformers excel at cooling due to oil being a superior cooling medium. They also support higher voltage capacities, with oil-immersed transformers having no voltage limits compared to the 35 kV limit of dry-type transformers. This makes oil-filled transformers more versatile.

 

Furthermore, oil-filled transformers are more environmentally friendly as they are easier to recycle than dry-type transformers. They are also smaller in size and better suited for outdoor environments, minimizing risks associated with oil spills or other accidents.

Purpose of Oil Immersed Transformers

 

Oil type transformers can be installed on the ground, on pads, or mounted on poles for outdoor use. They provide efficient performance across various applications, such as transmission and distribution networks, renewable energy generation, and small industries.

 

With their large capacity, oil transformers significantly conserve electrical energy, minimize power loss, save energy resources, and reduce costs for users. Additionally, the oil within the transformer cools the internal wire cores, enhancing the durability and electrical performance of the equipment.

Some cautions when using an Oil Immersed Transformers

 

Oil filled transformers rely on oil for their operation, making the quality of the oil crucial for the transformer's lifespan and safety. Regular inspections and maintenance of the transformer system are essential to ensure optimal performance and safety. Neglecting this can lead to issues and pose significant dangers.

 

Additionally, waste oil can easily pollute the environment, impacting the lives of nearby residents. Therefore, proper waste management and gradual treatment of used oil are also very important.

 

Conclusion 

 

To conclude, oil filled transformers are integral to various applications, such as providing efficient and reliable performance. However, maintaining the quality of the oil and ensuring regular maintenance are critical to the longevity and safety of these transformers. Proper management of waste oil is also essential to minimize environmental impact. By understanding and addressing these aspects, users can maximize the benefits of oil-filled transformers while mitigating potential risks.

 

In SANAKY, we are one of the top producers of transformers in Vietnam, and we have plenty of models that allow flexibility for our beloved customers. For further assistance in selecting the right product or for any inquiries, please feel free to leave a comment below or reach out to us via the provided email or phone number.