Dry Type VS Oil Immersed Transformer

Advantages and disadvantages of dry type transformer and oil imemrsed transformers.

• In price, dry type transformers becomes more expensive than oil immersed transformers.
• In capacity, large volumes of liquid immersed transformer more than cast resin dry type transformer.
• In comprehensive buildings and crowded places need to use dry transformer. The oil immersed type transformer is in an independent substation.
• In the construction according to the space to choose dry and oil filled transformer, large space can choose oil cooled transformer, choose dry type transformer when the space is crowded.
• Regional climate is humid hot areas, easy to use oil immersed transformer. If the use of dry transformer case, must be equipped with forced air cooling equipment.

1. Appearance

Different encapsulation forms, dry transformer can directly see the iron core and coil, and oil transformer can only see the transformer shell;

2. The lead form is different

Dry transformers mostly use silicone rubber bushing, and oil transformers mostly use porcelain bushing;

3. Voltage difference

Dry type transformer is generally suitable for distribution, the capacity is mostly below 2500KVA, the voltage is below 10KV, and there are individual 35KV voltage level; And the oil filled transformer can be from small to large to achieve all capacity, voltage levels also do all voltage; The ultra high voltage 1000KV test line being constructed in our country is certainly using oil type transformer.

4. Insulation and heat dissipation

Dry type transformers are generally insulated by resin, cooled by natural air, and cooled by large capacity fan, while oil ommersed transformers are insulated by insulating oil, and the coil generated by the circulating of insulating oil in the transformer will be cooled on the radiator (sheet) of the transformer.

5. Application

Dry type transformer is mostly used in the need of "fire, explosion-proof" places, generally large buildings, high-rise buildings easy to use; And oil immersed type transformer due to the "accident" after the possibility of oil ejection or leakage, resulting in fire, mostly used in the outdoor, and there is a site to dig the "accident oil pool".

6. The bearing of loads

Generally dry type transformer should run under rated capacity, and oil type transformer overload power is better.

7. Different cost

For the same capacity transformer, the purchase price of dry type transformer is much higher than that of oil immrsed transformer.

The biggest difference between oil-immersed transformer and dry transformer is that there is no "oil", and because the oil is liquid, with liquidity, oil-immersed transformer must be a shell, shell inside is transformer oil, oil soaked in the transformer coil, from the outside can not see the transformer coil; And dry transformer without oil, do not use the shell, can directly see the transformer coil; Another characteristic is that the oil-immersed transformer has oil pillow above, and the transformer oil is stored inside, but now the new oil-immersed transformer also has transformer production without oil pillow;

Oil-immersed power transformer in order to facilitate heat dissipation, that is, in order to facilitate the flow of internal insulation oil heat dissipation, the external design of the radiator, just like the heat sink, but the three phase  dry transformer does not have this radiator, heat dissipation depends on the transformer coil below the fan, the fan is a bit like the indoor unit of household air conditioning.

Oil-immersed distribution transformer due to the need for fire prevention, generally installed in a separate transformer room or outdoor, and cast resin transformer must be installed indoors, generally installed in low-voltage distribution room, and low-voltage distribution cabinet side by side installation.