Oil-immersed transformers take oil as the main means of transformer insulation and rely on oil as the cooling medium (self-cooling). Air cooling. Water). The main transformer of the general booster station is oil-immersed, and the ratio is 20kV / 500kV. The dry transformer relies on air convection for cooling. Small capacity transformer ratio 6000V/400V. Dry-type transformer and oil-type transformer, in addition to the same working principle, the biggest difference is that there is no oil inside the transformer, and there are many differences.
1, from the appearance, packaging forms are different, the dry type transformer can directly see the iron core and coil, and the oil type transformer can only see the transformer shell;
2, lead form is not the same, dry type transformers mostly use silicone rubber bushing, and oil type transformers mostly use porcelain bushing;
3, capacity and voltage is different, dry type transformer is generally suitable for distribution, capacity is mostly below 1600KVA, the voltage is below 10KV, there are individual do 35KV voltage level; The oil type transformer can be from small to large to do all the capacity, the voltage level also do all the voltage; The UHV 1000kV test line under construction in China must be oil-type transformer.
4. Insulation and heat dissipation are not the same, dry transformers generally use resin insulation, by natural air cooling, large capacity by fan cooling, and oil transformers by insulating oil insulation, insulating oil in the transformer internal circulation will be generated by the coil to the transformer radiator (piece) heat dissipation.
5, from the application site, dry transformers are mostly used in the need for "fire, explosion proof" places, generally large buildings, high-rise buildings are easy to use; And the oil type transformer because of the "accident" after there may be oil gushing or leakage, resulting in fire, most of the application in the outdoor, and there is a site dug "accident oil pool" place.
6, the bearing capacity of the load is different, the general dry transformer should be run at the rated capacity, and the overload capacity of the oil transformer is better.
7. The cost is different. For transformers with the same capacity, the purchase price of dry transformers is higher than that of oil-type transformers.
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