Shaanxi Hanzhong Transformer Co., ltd

Many people tend to confuse dry type transformers and oil filled transformers, and they can't tell the difference between dry type transformer and oil type transformer. Today, Shaanxi Hanzhong Transformer Co., Ltd. which is a professional china transformer manufacturer, will answer the difference between the two in detail.

Types of Transformer

Dry type transformer types are required to be used in comprehensive buildings like basements, floors, roofs and so on and densely populated fields. The oil transformer is used in an independent substation. Transformers in box substations generally use dry type transformers. Oil transformers are generally used for temporary outdoor electricity use. During construction, choose dry and oil transformers according to the space. When the space is large, you can choose an oil type transformer. When the space is more crowded, please choose dry transformers.

Dry Transformer vs Oil Transformer

In terms of price, dry type transformers are more expensive than oil filled transformers. In terms of capacity, there are more large-capacity oil filled transformers than dry type transformers.



Oil filled power transformer is easy to use in areas where the climate is relatively humid and sultry. If a dry type transformer is used, it must be equipped with forced air cooling.


Ⅰ. Appearances difference between oil and dry transformers


Different packaging forms, dry type transformers can directly see the iron core and coil, while oil filled transformers can only see the outer shell of the transformer.


Ⅱ. Lead forms difference between oil and dry transformers


Different dry type transformer mostly uses silicone rubber bushings, while most oil filled transformer uses porcelain bushings.


Ⅲ. Capacity and voltage difference between oil and dry transformers


Dry type transformers are generally suitable for power distribution. Most of the capacity is below 1600KVA, and the voltage is under 10K. Some of them can achieve 35KV voltage level. However, oil filled transformers can achieve full capacity from small to large, and the voltage level also achieves all voltages. The UHV 1000KV test line under construction in our country must use oil filled transformers.


Ⅳ. Insulation and heat dissipation difference between oil and dry transformers


Dry type transformers are generally insulated by resin and are cooled by natural air. The large capacity is cooled by fans, while oil filled transformers are insulated by insulating oil. The circulation of insulating oil inside the transformer transfers the heat generated by the coil to the radiator fin of the transformer for heat dissipation.


Ⅴ. Applications difference between oil and dry transformers


Dry type transformers are mostly used in places that require anti-fire and anti-explosion. Generally, they are easy to use in large buildings and high-rise buildings. Oil filled transformers may spray or leak after an accident, causing fires. Most of them are used outdoors. There are places where it is safe to dig oil.


Ⅵ. Load bearing capacity difference between oil and dry transformers


Generally, dry type transformer should be operated under rated capacity, while oil immersed type transformer has better overload capacity.


Ⅶ. Cost difference between oil and dry transformers


For transformers of the same capacity, the purchase price of dry type transformers is much higher than that of oil filled transformers. Dry type transformers generally start with SC, epoxy resin casting encapsulation type, SCR non-epoxy resin casting solid insulation encapsulation type, and SG open type. Dry type transformers mostly use silicone rubber bushings, while oil-type transformers mostly use porcelain bushings.

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