Dry Type Transformer vs Oil Type Transformer: Comparing the Differenes

What is a Dry-type Transformer?

Dry-type Transformer is a kind of transformer, which is characterized by its cooling method. Dry-type transformers do not rely on oil or other liquids for cooling and insulation, but rely on environmental air or through fan cooling.

The main characteristics include:

1.High safety: Due to the absence of a liquid medium, it is safer to use, reducing the risk of fire.

2.Easy to maintain: Since there is no oil, there is no need for regular replacement or addition of coolant, which greatly reduces maintenance costs and time.

3.High reliability: Due to its characteristics, dry-type transformers have good applications in places with high humidity or complex environments, such as underground facilities, chemical plants, etc.

4.Small environmental impact: Since oil is not used for cooling and insulation, it helps protect the environment.

5.Good heat dissipation effect: Compared with liquid cooling, air cooling is more effective and more suitable for high-temperature environments or environments with large loads.

Dry-type transformers are widely used in high-rise buildings, underground facilities, airports, platforms, hospitals, shopping centers, residential areas and other places that need electricity.

What is a oil-immersed transformer?

An oil-immersed transformer, also known as an oil-cooled transformer, is a type of transformer that uses insulating oil for cooling and insulation during operation. The core and windings inside the transformer operate while being immersed in insulating oil.

Its main features include:

1.Efficient Cooling: Liquids, such as transformer oil, typically have better thermal conductivity than air, so oil-immersed transformers can be cooled more effectively.

2.High Capacity: They come in a variety of sizes, from tens of kilovolt-amps to gigavolt-amps, and are used for various purposes, such as power transmission and distribution, thermal power stations, and nuclear power stations.

3.Maintenance Required: Since insulating oil is used, regular inspections and maintenance are necessary to ensure its good performance. This includes checking oil samples to see the content of particles and moisture in the oil.

4.Safety Issues: The insulating oil used in oil-immersed transformers may cause fires under high temperatures or arcs, so strict fire prevention measures are required.

Oil-immersed transformers are widely used in power systems, mainly for power transmission and distribution systems.

Dry Type Transformer vs Oil Type Transformer: Comparing the Differenes

Feature	Dry-Type Transformer	Oil-Immersed Transformer
Cooling Medium	Air	Insulating Oil
Insulating Material	Dry Air or Epoxy Resin	Insulating Oil
Environmental Requirements	Relatively lenient, not affected by ambient temperature	Consideration of ambient temperature and humidity
Fire Resistance	High fire resistance, less prone to fire incidents	Fire prevention facilities required, as insulating oil poses fire hazards
Maintenance and Inspection	Relatively simple, no frequent oil quality checks	Periodic checks of oil quality, maintenance, and addressing oil leaks
Fault Handling	Easy to locate and handle faults	Complex fault handling, involves dealing with insulating oil issues
Cost	Generally expensive, but costs are gradually decreasing with technological advancements	Initial investment is lower, but maintenance and oil management costs are higher
Usability	Suitable for special environments such as hazardous areas	Widely used in power systems, commonly found in substations and transmission lines

Which is more suitable for use in high-temperature environments, a dry-type transformer or an oil-immersed transformer?

In high-temperature environments, oil-immersed transformers might be a better choice compared to dry-type transformers. The reasons for this are as follows:

Better cooling effect: Insulating oil can effectively transmit and dissipate heat more efficiently than air. Therefore, in high-temperature environments, oil-immersed transformers can better cool the internal components of the transformer and prevent overheating damage.

Better insulation effect: The insulating oil of an oil-immersed transformer not only cools the transformer but also provides excellent electrical insulation. Under high-temperature environments, the insulation materials of dry-type transformers may be subjected to greater thermal stress and aging. In contrast, the insulating oil of oil-immersed transformers can better resist the effects of high temperatures on insulation.

Larger capacity: Because of their cooling and insulation effects, oil-immersed transformers generally can handle larger loads and capacities. This is particularly important in high-temperature environments, which more easily lead to overheating and overloading of equipment.

However, it is worth noting that while oil-immersed transformers are suitable for high temperatures, in practical applications, consideration must also be given to safety and maintenance costs. For example, oil-immersed transformers require strict fire prevention measures to prevent fires caused by insulating oil at high temperatures. Moreover, compared to dry-type transformers, oil-immersed transformers require more frequent maintenance and replacement of insulating oil. Therefore, in choosing a transformer, trade-offs need to be made based on actual needs and conditions.

What is the difference in the frequency of maintenance and replacement of insulating oil for oil-immersed transformers compared to dry-type transformers?

Comparing oil-immersed transformers to dry-type transformers, the maintenance schedule, especially relating to the insulation oil, tends to be more extensive.

Depending primarily on the usage and environment, the insulating oil in an oil-immersed transformer should be tested every 2-3 years, to assess factors like breakdown voltage, water content, acidity, etc. If the oil is contaminated or has degraded, it needs to be purified, reconditioned, or on occasion replaced entirely.

On the other hand, dry-type transformers are essentially maintenance-free in regards to coolants since they rely on air cooling instead of oil. This brings a clear advantage when summing up the ongoing service costs. Conducting an annual general inspection to check for any dust buildup or obstructions to the airflow is usually sufficient.

Of course, these periods can vary based on the specific usage conditions and demands. Although dry-type transformers require less routine servicing, both transformer types still need regular inspections to ensure continuous efficient, and safe operations.