Transformers can be divided into dry-type transformers and oil immersed transformers. What is the difference between them and how to choose them in actual purchase?
In terms of price, dry-type transformer is more expensive than oil immersed transformer.
Dry transformer is required in complex buildings (basement, floor, roof, etc.) and densely populated places. The oil transformer is used in an independent substation. The transformer in the box transformer generally adopts dry transformer. Oil transformer is generally used for outdoor temporary power. During construction, dry transformer and oil transformer are selected according to the space. Oil transformer can be selected when the space is large, and dry transformer can be selected when the space is crowded.
The regional climate is humid and muggy, so it is easy to use oil change. If dry transformer is used, forced air cooling equipment must be equipped.
Different packaging forms, dry-type transformer can directly see the iron core and coil, while oil transformer can only see the shell of the transformer.
2. Different lead forms
Silicone rubber bushing is mostly used in different dry-type transformers, while porcelain bushing is mostly used in oil transformers.
3. Different capacity and voltage
Dry type transformers are generally suitable for power distribution. Most of the capacity is below 1600KVA and the voltage is below 10K. Some of them can achieve 35kV voltage level, while oil transformers can achieve all the capacity from small to large, and the voltage level can also achieve all the voltages. The UHV 1000kV test lines under construction in China must adopt oil transformers.
4. Insulation and heat dissipation are different
Dry type transformers are generally insulated with resin, which is cooled by natural air, and large capacity is cooled by fan. Oil type transformers are insulated by insulating oil, and the heat generated by the coil is transferred to the radiator fin of the transformer by the circulation of insulating oil inside the transformer.
5. Applicable place
Dry type transformers are mostly used in places where “fire prevention and explosion-proof” are required, which are easy to be used in general large buildings and high-rise buildings. Oil transformers are mostly used outdoors, and there are places where “accident oil pool” is excavated because oil may eject or leak after “accident”.
6. Different load bearing capacity
Generally, dry-type transformer should operate under rated capacity, while oil transformer has better overload capacity.
7. Different cost
For transformers with the same capacity, the purchase price of dry-type transformer is much higher than that of oil type transformer. The model of dry-type transformer generally starts with SC, epoxy resin casting encapsulated type, SCR non epoxy resin casting solid insulation encapsulated type and SG open type. Most dry-type transformers use silicone rubber bushing, while most oil transformers use porcelain bushing.