Advantages and disadvantages of dry type transformer and oil immersed transformer
Dry conversion is more expensive than oil in price.
In terms of capacity, there are more oil transformers with large capacity than dry ones.
Dry transformer should be used in complex building (basement, floor, roof, etc.) and crowded places. Oil transformer is used in independent substation.
The transformer inside the box transformer generally adopts the box transformer. Oil transformer is generally used for outdoor temporary power consumption.
In construction, dry transformer and oil transformer are selected according to space, oil transformer can be selected when space is large, and dry transformer is selected when space is crowded.
The regional climate is relatively humid and muggy, easy to use oil change. If dry type transformer is used, it must be equipped with forced air cooling equipment.
1. Appearance
The core and coil can be seen directly in dry-type transformer, while only the shell can be seen in oil-based transformer;
2. Different lead forms
Most dry-type transformers use silicone rubber bushing, while most oil transformers use porcelain bushing;
3. Capacity and voltage are different
Dry type transformer is generally suitable for distribution, with capacity below 1600KVA, voltage below 10kV, and some of them reach 35kV voltage level; however, oil type transformer can achieve full capacity from small to large, and the voltage level can also achieve all voltages; oil type transformer must be used in the 1000kV UHV test line under construction in China.
4. Insulation is not the same as heat dissipation
Dry type transformer is generally insulated by resin, cooled by natural air, and cooled by fan for large capacity, while oil type transformer is insulated by insulating oil, and the heat dissipation is carried out on the radiator (fin) of transformer by the circulation of insulating oil in the transformer.
5. Applicable place
Most of the dry-type transformers are used in places where "fire-proof and explosion-proof" are needed, which are easy to be used in large-scale buildings and high-rise buildings. However, oil-based transformers are mostly used outdoors because of the possibility of oil gushing or leaking after an accident, and there are places where "accident oil pools" are excavated.
6. The bearing capacity of the load is different
Generally, dry-type transformer should operate at rated capacity, while oil type transformer has better overload capacity.
7. The cost is different
For the same capacity transformer, 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)
Difference between dry type transformer and oil immersed transformer
"Of course, the same thing is that all power transformers have iron cores for magnetic circuits and windings for circuits. The biggest difference is in "oil" and "dry". In other words, the cooling medium of the two is different. The former uses transformer oil (of course, other oil such as β oil) as cooling and insulating medium, while the latter uses air or other gases such as SF6 as cooling medium. Oil transformer is to place the body composed of iron core and winding in a tank full of transformer oil. The iron core and winding are often encased with epoxy resin pouring in dry transformer. There is also a kind of non enclosed type which is used more now. The winding is impregnated with special insulating paper and special insulating varnish to prevent the winding or iron core from getting damp. (and because the two categories are derived from different classification methods in terms of technology, use and structure, we can say it in a narrow sense)
In terms of output and consumption, at present, the voltage level of dry transformer is only 35kV, and the capacity is smaller than that of oil transformer, which is about 2500kVA. So at present, the amount of oil is still increasing. However, due to its environmental protection, flame retardant, shock resistance and other advantages, it is often used in indoor power supply and distribution stations with high requirements, such as hotels, office buildings, high-rise buildings, etc. If you're just a transformer user, it's enough to know that. "
Each has its own advantages and disadvantages. The oil transformer has low cost and convenient maintenance, but it is flammable and explosive. Due to its good fire resistance, dry transformer can be installed in the load center area to reduce voltage loss and power loss. But dry transformer price is high, volume is big, moistureproof dustproof is poor, and noise is big.
The dry type transformer can be disassembled and transported for convenience. It is clean and easy to maintain. It does not need engine base and has no oil leakage pool
It is better to distinguish from the appearance;
The biggest difference between oil immersed transformer and dry-type transformer is whether there is "oil". Because oil is liquid and has fluidity, oil immersed transformer must have a shell. The inside of the shell is transformer oil, and the coil of transformer is soaked in oil, so the coil of transformer can not be seen from the outside. However, dry-type transformer does not have oil Another feature is that there is a conservator on the top of the oil immersed transformer and the transformer oil is stored inside. However, the new type of oil immersed transformer is also produced without oil conservator;
For the convenience of heat dissipation, i.e. for the flow and heat dissipation of the internal insulating oil, the oil immersed transformer has designed a radiator outside, just like the heat sink. However, the dry-type transformer does not have this radiator. The heat dissipation depends on the fan under the transformer coil, which is a bit like the indoor unit of the household air conditioner;
Due to the need of fire prevention, oil immersed transformer is generally installed in a separate transformer room or outdoor, while dry-type transformer must be installed indoors. Generally, it is installed in low-voltage distribution room and installed side by side with low-voltage distribution cabinet.
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