KR200375025Y1 - Transformer cooling device using refrigerant vaporization heat of refrigeration cycle - Google Patents

Abstract

The present invention relates to a transformer cooling device that further enhances the cooling effect by cooling the heat generated from the transformer using a refrigeration cycle.

In the transformer, heat is generated by no-load loss and load loss. Small transformers are cooled by natural air cooling, but this method is difficult to apply as the transformer capacity increases. If the heat is not removed, the insulating material surrounding the transformer winding is degraded by the deterioration phenomenon, and if the degree is severe, the internal breakdown of the transformer may be caused by the insulation breakdown. Therefore, the transformer capacity is determined by the degree of cooling the heat applied to the transformer. As the voltage of the power system increases to 154kV, 345kV, 765kV, etc., the transformer capacity is increased and the transformer loss is increased. Therefore, it is necessary to effectively remove heat generated in the transformer. Conventionally, natural cooling through radiators and forced cooling by insulating oil circulation pumps and blowers have been used. In the case of underground substations, water cooling is used.

In recent years, even if there is a need to construct a new substation in the city center, there is a lack of site to build and there is a lot of opposition. Therefore, it is important to increase the capacity of the existing transformer by effectively removing the heat generated from the existing transformer. .

In the present invention, a phenomenon in which a refrigerant is vaporized in a refrigeration cycle and absorbs heat of vaporization from the surroundings is used for cooling the transformer. By changing the structure of the transformer radiator 11, the evaporator 41, which is a refrigerant vaporization part of the refrigerating cycle, was installed to contact the inside of the radiator or the radiator so as to effectively remove the heat of the insulating oil entering the transformer radiator 11. Since the vaporized refrigerant has physical energy due to volume expansion, a turbine 51 is installed between the radiator 41 and the compressor 45 of the refrigeration cycle by using this, and a generator (or a mechanical device) on the shaft of the turbine 51 is used. 52) to obtain electrical or physical energy.

Description

Transformer cooling device using refrigerant vaporization heat of refrigeration cycle

Since transformers have different lifespans depending on the degree of deterioration of the insulation wound around the transformer windings, the capacity associated with the transformer's allowable current also depends on the method of removing the heat applied to the transformer so that the winding insulation does not deteriorate. A power loss of about 340 kW for a 154 kV 45/60 MVA transformer, about 1,200 kW for a 345 kV 500 MVA transformer, and about 5,100 kW for a 765 kV 2000 MVA transformer occurs. This loss becomes heat inside the transformer and heats the insulating oil filled around the winding, which releases the heat thus obtained from the transformer body or radiator to the atmosphere by convection. When the capacity is small, natural cooling is performed. When the capacity is large, the insulating oil is forced to circulate to the radiator, and the cooling blower 31 installed around the radiator is operated to increase the cooling effect. However, although the blower consumes a lot of electricity to blow the wind, the generated wind does not have effective heat exchange with the radiator. Since the heat exchange with the atmosphere in such an inefficient way, a large radiator is needed to increase the cross-sectional area of the radiator, and even the radiator size is as large as the transformer body, which causes a large substation area. Recently, with the construction of underground substations in urban areas, the cooling problem becomes more and more serious. Underground substations use a water cooling system that cools the underground transformers by creating cooling water in the cooling towers above the ground.

The present invention proposes a cooling device that changes the structure of the transformer radiator 11 to facilitate heat exchange with the evaporator 41 in which the refrigerant of the refrigerating cycle is evaporated, thereby effectively removing heat applied to the transformer. First, the transformer radiator 11 and the evaporator 41 of the refrigerating cycle are made smaller in size in consideration of the effective heat exchange. In the case of underground substations, a separate type that allows the heat absorbing heat from the transformer to move away from the transformer to be removed may be separated from the location where the heat is absorbed from the transformer. Since the refrigerant evaporated in the evaporator 41 has physical energy due to volume expansion, a turbine 51 is installed between the radiator 41 and the compressor 45 of the refrigerating cycle to obtain a rotational force by using the refrigerant. A generator (or mechanical device) 52 is installed on the shaft to obtain electrical energy or physical energy.

1 is a perspective view of a conventional transformer.

2 is a front view of a transformer.

3 is a diagram illustrating a conventional transformer cooling method.

4 is an explanatory diagram of a transformer cooling device using refrigerant vaporization heat of a refrigeration cycle.

5 is an explanatory diagram in which an energy recovery device using a vaporization physical force of a refrigerant is added.

6 is an explanatory diagram of the annual temperature sustain curve of the transformer.

<Description of the code | symbol about the principal part of drawing>

11: transformer radiator 12: transformer body

13: Conservator 14: Bushing

31: cooling blower 41: evaporator

42: expansion valve (or capillary tube) 43: refrigerant storage tank

44 condenser 45 compressor

46: motor (or engine) 51: turbine

52: generator (or mechanism) 61: cooling zone

62: additional cooling zone

1 is a perspective view of a conventional transformer. It can be seen that a large transformer radiator 11 is attached to the transformer body 12 in parallel so that the total size of the transformer becomes larger.

2 is a front view of a transformer. It can be seen that the transformer radiators 11 are attached to the left and right sides of the transformer body 12.

3 is a view illustrating a wind-cooled cooling method of an existing transformer. The insulating oil heated in the transformer body 12 moves to the upper portion of the transformer body 12 by convection, and the insulating oil flows into the transformer radiator 11 and enters through a plurality of separated pipes, thereby greatly increasing the area in contact with the atmosphere. While cooling down, it cools by exchanging heat with the atmosphere. The cooled insulating oil descends below the transformer radiator 11 and then flows back into the transformer body 12 to end one cycle of convection. In order to increase the cooling effect, the cooling blower 31 installed around the transformer radiator 11 may be operated.

4 is an explanatory view of a cooling apparatus using refrigerant vaporization heat of a refrigerating cycle according to the present invention. In the present invention, the refrigeration cycle is composed of a compressor 45, a condenser 44, a refrigerant storage tank 43, an expansion valve (or capillary tube) 42, the evaporator 41. The compressor 45 compresses the refrigerant in a gaseous state, and in the condenser 44, the compressed refrigerant dissipates heat to become liquid, and the refrigerant, which becomes liquid, is supplied to the refrigerant storage tank 43 installed to increase the inertia of the cooling system. As the liquid phase cools down, the liquid refrigerant passes through the expansion valve (or capillary tube) 42, causing a state change to a gaseous state and the volume starts to expand. The refrigerant exiting the expansion valve (or capillary) 42 becomes a gas while absorbing heat of vaporization from the evaporator 41 connected to the expansion valve (or capillary) 42. In order to enhance the cooling effect, the transformer radiator 11 and the evaporator 41 that exchange heat are installed in parallel. The gas passing through the evaporator 41 enters the compressor 45 and is compressed to end one cycle of the refrigeration cycle. The transformer radiator 11 completely surrounds the evaporator 41 and the insulating oil contacts the surface of the evaporator 41 so that the evaporator 41 of the refrigeration cycle exchanges heat well with the transformer radiator 11. By installing all of the cooling devices as shown in Figure 4 in a plurality of transformer radiators 11 installed in parallel in the transformer body 12 to prevent the cooling of the transformer even if some of the cooling device failure. If the heat of the transformer can be easily removed, the same effect as a superconducting transformer can be obtained. It is also within the scope of the present disclosure to remove the refrigerant storage tank 43 installed between the expansion valve (or capillary tube) 42 and the condenser 44. In consideration of the considerably large transformer loss power, it is also included in the scope of the present invention to operate the cooling blowers 31 in parallel around the transformer radiator 11 cooled by the refrigeration system. Recently, since substations are often installed in buildings or underground, heat exchange between the transformer radiator 11 and the evaporator 41 takes place near the transformer, thus moving the heat absorbed by the gaseous refrigerant to another place far away. It is also within the scope of the present invention to construct a refrigeration system in a separate type to be able to move the heat in the indoor or underground space to the outside by compressing to 45 and dissipating heat absorbed by the condenser 44. The transformer radiator 11 can be easily separated and assembled from the transformer body 12 so that the cooling device according to the present invention can be treated as an accessory of the transformer radiator 11.

5 shows that the turbine 51 is installed between the evaporator 41 and the compressor 45 so that the turbine 51 can be turned by the physical force generated as the vaporized refrigerant becomes gas and expands in volume. Turbine 51 shaft is provided with a generator (or a mechanical device) 52 to obtain electrical energy or physical energy, energy production is also possible. The gaseous refrigerant that rotated the turbine 51 enters the compressor 45 and is compressed again to start a new cycle.

FIG. 6 is a graph in which the temperature applied to the transformer during one year of operation of the transformer is arranged in order from high to low. Transformer temperature varies with transformer load and ambient temperature. The area corresponding to the temperature above the transformer allowable temperature corresponds to the cooling area 61 and is cooled by the existing cooling method. However, when overloading the same transformer, the transformer temperature rises like the overload operation curve, and an additional cooling zone 62 is required, which requires additional cooling. If this zone is cooled by the cooling device according to the present invention, the transformer is a conventional concept. Unlike this, it is possible to operate up to more capacity, so it is very useful when overload operation is required in the area where substation construction is difficult such as downtown.

By cooling the heat applied to the transformer using the refrigerant vaporization heat by the refrigeration cycle, the heat can be effectively cooled to increase the capacity of the transformer and increase efficiency. In addition, by reducing the size of the transformer radiator 11 by cooling the transformer by a method of stronger refrigeration than the conventional methods such as natural cooling or air cooling or water cooling, the size of the substation site can be drastically reduced. In addition, the turbine 51 may be turned by the physical force due to the volume that is expanded during the vaporization of the refrigerant to produce electrical energy or physical energy.

Claims (2)

A plurality of evaporator 41 and transformer radiator 11 heat exchangers in which the evaporator 41 is completely enclosed by the transformer radiator 11 and the transformer insulating oil is in contact with the surface of the evaporator 41; Multiple evaporators 41 and transformer radiators 11 Heat exchangers, compressors 45, condensers 44, refrigerant storage tanks 43, multiple expansion valves (or capillaries), again multiple evaporators 41 and transformers Radiator (11) Transformer cooling device using the refrigerant vaporization heat of the refrigeration cycle characterized in that the cooling cycle is connected to the tube in order to circulate to the heat exchanger. A turbine (51) added between the plurality of evaporators (41) and the transformer radiators (11) of the heat exchanger and the compressor (45); Transformer (51) using the refrigerant vaporization heat of the refrigeration cycle characterized in that the generator (or mechanism) 52 connected to the shaft of the turbine (51).