What Is The Difference Between Dry-type Transformers And Oil-immersed Transformers

The price of dry transformation is higher than that of oil transformation.

In terms of volume, the volume of large volume oil should be greater than the dry volume.

In complex buildings (basements, middle floors, rooftops, etc.) and areas with a large number of people, dry transformers are required. Hydraulic frequency converters are used in discrete substations.

In box type substations, box type substations are usually used. For temporary outdoor electricity use, hydraulic frequency converters are usually used.

During construction, dry type transformers and oil type transformers should be selected according to the size of the construction site. When the site is relatively large, oil type transformers can be selected, and when the site is relatively narrow, dry type transformers can be selected.

The climate in this region is relatively humid and stuffy, making it prone to oily changes. If the dry state is used, a forced air cooling device needs to be equipped

1. Appearance

On the packaging, dry type transformers can directly see the iron core and winding, while oil type transformers can only see the outer cover;

2. Different wire shapes

There are more dry type transformers with silicone rubber sleeves, while there are fewer oil type transformers with ceramic sleeves;

3. Different capacities and voltages

Dry type transformers commonly used for power distribution have a capacity of 1600 kVA, below 10 kV, and a few can reach a voltage level of 35 kV; The oil pressure converter can achieve maximum capacity and maximum voltage; At present, there are inevitably oil transformers in the 1000 KV ultra-high voltage test lines under construction in China.

4. Different insulation and heat dissipation properties

In general, dry-type transformers use resin insulation, which relies on natural air cooling. In high-capacity cases, they rely on fans for cooling. However, oil-type transformers rely on insulating oil for insulation, which circulates inside the transformer to dissipate heat from the heat generated by the coil to the radiator (fin) of the transformer.

5. Place of use

Dry type transformers are often used in places with "fire and explosion proof" requirements, and are often used in large buildings and high-rise buildings; Oil transformers, on the other hand, can cause fires due to oil leakage or oil leakage after an accident, and are often used outdoors, requiring excavation of "accident oil pools" in the wild.

6. Load bearing capacity

Normally, dry type transformers should operate within the rated power range, while oil type transformers prefer overload power.

7. Different costs

For transformers of the same capacity, the cost of purchasing dry type transformers is higher than that of oil type transformers.

The models of dry-type transformers usually come in three forms: SC, SCR, non epoxy, and SG.

Differences between oil immersed and dry type transformers

Of course, they all have one thing in common, which is that they both have an iron core as a magnetic circuit and a coil. However, the biggest difference lies in the "dry" and "oil" types. That is to say, the cooling medium used by the two is different. The former uses transformer oil (of course, there are other oils, such as β Oil), while the latter uses air or other gases such as SF6. The oil transformer is to put a device composed of iron core and coil into an oil tank filled with transformer oil. The dry transformation type usually uses epoxy resin to wrap the iron core and coil, and there is also a non wrapping type of coil. The coil is coated with a special insulating paper and a layer of special insulating paint, which can prevent the coil or coil from being affected by moisture. In terms of production and usage, the current voltage level of the dry transformer is only 35 kV, with a smaller capacity compared to the oil transformer, approximately 2500 kVA. And because the manufacturing process of dry transformers is more complex and costly than oil transformers of the same voltage level and capacity. So in terms of quantity, the current oil volume is still increasing. However, due to the advantages of being dry, environmentally friendly, flame retardant, and impact resistant, it is often used in places that require high temperatures such as hotels, office buildings, and high-rise buildings. For ordinary transformer users, these are sufficient Due to its excellent fire resistance, dry transmitters can be installed in the load center area to reduce voltage loss and power loss. However, dry-type transformers are expensive, bulky, resistant to moisture and dust, and have significant noise.

The oil transformation is gradual and can be disassembled using dry transformation, which is convenient for transportation and maintenance. It does not require a base for installation and has no leakage. Its advantages are relatively easy to identify from the appearance; photo example

The biggest difference between oil-immersed transformers and dry-type transformers is the presence of "oil". Since oil is liquid, oil-immersed transformers must have an outer cover that contains the transformer's oil, and the coil cannot be seen from the outside. Due to the absence of oil, dry-type transformers do not require the use of a casing and can directly observe the windings of the transformer; Another feature is that there is an oil conservator on the top of the immersed transformer to store the transformer oil oil. At present, there are transformers without oil conservator in the new immersed transformer;

In order to facilitate heat dissipation, an oil immersed transformer is designed with a heat sink on the outside, just like a heat sink. However, dry-type transformers do not have this heat sink, but rely on a fan below the transformer coil for heat dissipation, which is somewhat similar to indoor units in household air conditioners.

Due to fire protection requirements, oil immersed transformers are usually installed in an independent substation or outdoors, while dry type transformers must be installed indoors, usually in a low-voltage distribution room, and in parallel with low-voltage distribution cabinets.

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http://www.switchgear-china.com/power-distribution-transformer/dry-type-transformer/11kv-dry-type-amorphous-core-transformer.html

http://www.switchgear-china.com/power-distribution-transformer/oil-immersed-transformer/10kv-oil-immersed-transformer.html

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