Introduction to high frequency transformer cooling method

2019-06-24 10:54:16 JUKE CHINA ODM OEM Transformer factory Read

Introduction to high frequency transformer cooling method

     The common cooling methods for High frequency transformers are mainly oil-immersed self-cooling (ONAN); oil-immersed air-cooling (ONAF); forced oil circulating air cooling (OFAF); forced oil circulating water cooling (OFWF); forced-oriented oil circulating air cooling (ODAF) ); forced-oriented oil circulation water-cooled ODWF). According to the requirements of the transformer selection guidelines, the selection of cooling methods is recommended as follows:
 
1. Oil immersion self-cooling: By immersing the transformer windings in the transformer oil, the heat is transferred to the oil pipe radiator by the natural thermal cycle of the oil, and is naturally ventilated and cooled by the oil pipe radiator. Mainly suitable for: 3,500kVA and below, 35kV and below; 50000kVA and below, 110kV products.
 
2, oil-immersed air-cooled: the winding is immersed in the transformer oil, relying on the natural thermal cycle of the oil to bring the heat to the oil pipe radiator, and is cooled by the electric fan. Mainly suitable for: 12500kVA ~ 63000kVA, 35kV ~ 110kV products; 75000kVA or less, 110kV products; 40000kVA and below, 220kV products.
 
3. Forced oil circulation air cooling: The oil circulation is forced by the transformer oil pump to make the oil flow through the air cooler for cooling. Mainly suitable for: 50000 ~ 90000kVA, 220kV products.
 
4. Forced oil circulation water cooling: a cooling method in which the oil pump is forced by the transformer oil pump to make the oil flow through the water cooler for heat dissipation. Mainly suitable for: general hydropower plants with boost voltages of 220kV and above, 60MVA and above.
 
5. Forced-oriented oil circulation air-cooling or water-cooling: (The cooling method of using the transformer oil pump to force the oil circulation to make the oil flow through the water cooler for heat dissipation. ODAF or ODWF) is mainly suitable for: 75000kVA and above, 110kV products; 120,000kVA And above, 220kV products; 330kV and 500kV products.
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When the oil-cooled cooling method is selected, when the oil pump and the fan lose power supply, the transformer cannot be operated for a long time. It can't run for a long time even if it is empty. Therefore, two separate power supplies should be selected for use by the chiller. When the oil-cooled water cooling method is selected, when the oil pump cooling water loses power, it cannot be operated. The power supply should select two independent power supplies.
    There is no special cooling device for oil intrusion. It uses the natural convection of oil to bring the heat from the windings and core to the tank wall or tube (slice) radiator, and then rely on the convection conduction of air to transfer heat. Distribute. This cooling method is often used for small capacity transformers. The oil intrusion type is on the inner side of the transformer-disassembled radiator, and a cooling fan is installed to accelerate the cooling of the oil in the radiator by using a fan blower. The same transformer, with air-cooled cooling, can increase capacity by 30-35%. Medium-capacity transformers generally use air-cooled cooling. Forced air cooling and strong oil water cooling are two ways of cooling the hot oil in the transformer tank, using an oil pump to enter the oil cooler, after cooling, return to the fuel tank, cooling the windings and the fuel tank. The oil cooler is made into a special shape that is easy to dissipate heat, and the heat of the oil is taken away by using a fan blower or circulating water as a cooling medium. These two cooling methods have a strong cooling effect, and these two cooling methods are commonly used in large-capacity transformers.
Dry-type transformers can be cooled in two ways: 1. AN-air (circulating) natural cooling; 2. AF-air blowing cooling. According to the technical requirements of dry-type transformers, the transformer can meet the rated operation requirements under the condition of AN cooling. However, dry-type transformers usually have fans, which are used for emergency use by users. So strictly speaking, dry-type transformers have only one cooling method, that is, the air is naturally cooled.