The Difference Between Dry-type Transformers and Transformer Oil Immersed Type

Many people are easy to confuse dry transformers and transformer oil immersed types and cannot tell the difference between them. In the complex building (basement, floor, roof, etc.) and crowded places need to use dry transformer. Transformer oil immersed type is used in an independent substation. The transformer in the box generally adopts dry-type transformers, and the outdoor temporary electricity is usually transformer oil immersed type. During construction, dry-type transformer and transformer oil immersed type are selected according to the space. Transformer oil immersed type can be selected when the space is large, and dry-type  transformer can be selected when the space is crowded. In areas where the regional climate is humid and hot, it is advisable to use transformer oil immersed types. If dry-type transformer is used, it must be equipped with forced air cooling equipment.

Ⅰ. Appearance of dry-type transformers and transformer oil immersed types

Different packaging forms: dry-type transformer cores and coils are exposed, while transformer oil immersed types expose the outer casing of the transformer. Different lead forms: different dry-type transformers mostly use silicone rubber bushing, and transformer oil immersed types mostly use porcelain bushing.

Ⅱ. Voltage and heat dissipation for dry-type transformers and transformer oil immersed types

Different capacities and voltages: dry-type transformers are generally suitable for power distribution. Most of the capacity is below 1600KVA, the voltage is below 10K, and some have a voltage level of 35KV, while transformer oil immersed types can achieve full capacity. The voltage level has also achieved all voltages, and many UHV 1000KV test lines must use transformer oil immersed types.

Different insulation and heat dissipation: dry-type transformers are generally insulated with resin, which is cooled by natural air, and large capacity fan cooling, while the transformer oil immersed type is insulated by insulating oil, and the circulation of the insulating oil inside the transformer transfers the heat generated by the coil to the radiator of the transformer for heat dissipation.

Ⅲ. Load capacity of dry-type transformers and transformer oil immersed types

Different load bearing capacity: Generally, dry-type transformers should operate at rated capacity, while transformer oil immersed types have better overload capacity. Different cost: For transformers of the same capacity, the purchase price of dry-type transformers is much higher than that of transformer oil immersed types. Dry-type transformers models generally start with SC, which is different from 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 transformer oil immersed types most use porcelain sleeves.

Dry-type transformers are mostly used in places that require "fire prevention and explosion-proof". Generally, large buildings and high-rise buildings should use dry-type transformers. Transformer oil immersed types may have oil spray or leakage after an "accident", causing fires. Most of them are used outdoors and the places where "accident oil pools" are excavated.