Both dry-type transformers and oil-immersed transformers are power transformers. What is the difference between them?
1. External appearance and shape
Dry-type transformers generally do not have a casing, and the core and coil can be seen directly; oil-immersed transformers have a casing, and the internal structure of the transformer cannot be seen.
2. The form of the lead wire
Silicone rubber bushings are used for dry-type transformers; porcelain bushings are used for oil-type transformers.
3. Different insulation and heat dissipation
Dry-type transformers are usually insulated with resin and cooled with natural air. Large-capacity transformers are cooled by fans; oil-type transformers are insulated with insulating oil. The insulating oil circulates inside the transformer to transfer the heat generated by the coil to the radiator fins of the transformer to dissipate heat.
4. Different capacities and voltages
Oil-immersed transformers have a larger capacity than dry-type transformers. Dry-type transformers are generally suitable for power distribution. Most of the capacity is below 1600KVA, the voltage is below 10KV, and some voltage levels are below 35KV; oil-type transformers can almost achieve full capacity, and all voltage levels can be made.
5. Different load capacity
Generally speaking, dry-type transformers should be operated at rated capacity, while oil-type transformers have better overload capabilities.
6. Different costs
For transformers with the same capacity, the purchase price of dry-type transformers is much higher than that of oil-type transformers.
7. Applicable places
Dry-type transformers are generally used in complex buildings (basement, middle floors, roofs, etc.) and places that require "fireproof" and "explosion-proof" such as densely populated places, and oil transformers are used in independent substation places.