how to cool the transformer at high temperatures

You're afraid of heat, and the distribution transformer is afraid of heat! In fact, the transformer may indeed fail due to overheating under certain conditions, and today we will talk about the cooling system of the transformer and how to cool the transformer at high temperatures.

 

Transformer overheating is a phenomenon that occurs during the operation of the transformer. It may cause a series of problems such as insulation aging, winding burnout, and oil deterioration in oil-immersed transformers, all of which may cause serious failures or even damage to the transformer.
In hot weather, the coil of the transformer will heat up more easily, which will affect its efficiency. If the heat cannot be dissipated in time, it may cause the coil to burn out, and in severe cases, it may even cause a fire. This will not only affect the normal operation of the transformer, but may also cause safety hazards to the surrounding environment and equipment.
High temperature will also cause the performance of the transformer's insulation material to deteriorate, thereby affecting its electrical performance. As the temperature rises, the insulation resistance of the insulation material will decrease, resulting in an increase in leakage current, and in severe cases, it may even cause a short circuit accident. In addition, the life of the insulation material will also be shortened, increasing the risk of transformer failure.

 

Two， How to cool down the transformer
In the hot summer, people need fans and air conditioners, and power transformers must also be cooled. So how to cool down the transformer?
The transformer itself is designed with heat dissipation in mind and is equipped with a cooling system. The cooling system of the transformer is divided into two parts: the internal cooling system and the external cooling system. The internal cooling system is to ensure that the heat of the core and winding is dissipated into the surrounding medium. The external cooling system is to ensure that the heat of the medium can be dissipated outside the transformer. The external cooling system usually includes radiators, fans, water pumps and other systems.
The cooling system of the transformer can be divided into many types according to the cooling medium and cooling method. Common cooling methods include natural cooling, oil immersion cooling, forced oil circulation cooling, air cooling, water cooling, evaporative cooling and phase change material cooling.
Natural cooling: Use air convection and radiation to dissipate the heat generated by the transformer into the surrounding environment. This cooling method is simple and economical, but the cooling effect is greatly affected by factors such as ambient temperature and humidity. It is suitable for transformers with small capacity and low load. This cooling method has little effect in hot weather.

Oil-immersion cooling: The insulating oil in the transformer tank is used as a heat transfer medium. The heat is transferred to the outside of the tank through the circulation of the oil, and then the heat is dissipated into the air through the radiator. This cooling method has good heat dissipation effect and is suitable for large-capacity and high-load transformers. However, the insulating oil needs to be replaced regularly, and the maintenance cost is high. In addition, under high temperature conditions, the oil temperature will also rise, and excessively high oil temperature will also affect its cooling effect.

Air-cooled cooling: A radiator is installed outside the transformer tank, and the radiator is blown by a fan to dissipate the heat into the air. This cooling method is suitable for small transformers. The heat dissipation effect is greatly affected by factors such as ambient temperature and humidity, but the maintenance cost is low.

 

Water-cooled cooling: A water-cooled radiator is installed outside the transformer oil tank, and the heat is dissipated into the water through the contact between water and the radiator. This cooling method has a good heat dissipation effect and is suitable for large transformers, but it consumes water resources and has high water quality requirements.

The cooling method of the transformer is generally represented by a combination of four codes:

Dielectric type		Cycle type
Mineral oil	O	natural c	N
Noncombustible synthetic insulating fluid	L	Forced circulation of oil is not guided	F
Gas	G	Forced circulation oil guide	D
Water	W
Air	A

For example: ONAN means oil-immersed self-cooling, that is, natural circulation of internal oil and natural circulation of external air.
The above cooling methods are all cooling methods used in daily operation of transformers. In daily life, power system personnel are also required to regularly detect the status of the transformer and regularly check and record the upper oil temperature. The upper oil temperature of the transformer with natural circulation should generally not exceed 85°C to prevent accelerated deterioration of the insulation material. At the same time, regular monitoring of load and current, increased power consumption in summer, long-term overload operation of transformers is more likely to overheat. For the situation of unbalanced three-phase load, timely adjustments should be made to maintain balanced power supply.

However, under high temperature conditions, if the cooling effect cannot be achieved by relying on the transformer's own cooling system, the power grid staff will have to use some auxiliary means, such as evaporative cooling, convection heat exchange, etc.

Put ice cubes under the transformer and use the principle of heat absorption and evaporation of ice cubes to cool the transformer

 

In addition, the cooling system can be optimized and some new cooling methods can be adopted.  introduced a main transformer condensation intelligent rapid cooling device, which used a "special air conditioner" for the transformer. This system can produce dry cold air 20°C lower than the ambient temperature and transport it to the bottom of the main transformer through pipes to achieve efficient cooling.

In short, through the transformer's own cooling system, strengthen monitoring and maintenance, the use of new cooling methods and other measures, can effectively ensure the safe operation of the transformer in high temperature weather.