KR200382236Y1 - Underground distribution transformer applying refrigeration cycle to cooling system - Google Patents

Abstract

The present invention changes the structure of the inlet-cooled existing underground distribution transformer (aka PAD transformer, inlet-cooled ground-mounted transformer) and applies the refrigeration cycle to the cooling device to cool the heat generated from the underground distribution transformer using the refrigeration cycle. The present invention relates to an underground distribution transformer having a higher cooling effect.

In the transformer, heat is generated by no-load loss and load loss. 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, it causes the internal breakdown of the transformer by the insulation breakdown. Therefore, the transformer capacity is determined by the degree of cooling the heat applied to the transformer. Conventional underground distribution transformers are inflow-cooled ground-mounted transformers that are connected to the distribution system and installed on the ground using 6.6kV and 22.9kV underground distribution lines. Therefore, many underground distribution transformers are installed in urban areas where many underground lines are installed. However, due to cooling problems, the installed capacity is increased due to the limited transformer capacity. However, as shown in FIG. 7, when the capacity is increased, the time for which the transformer temperature is a problem is very short.

In the present invention, the capacity of the transformer can be increased by cooling the transformer by an effective freezing method for this short time. If the capacity of underground distribution transformers can be increased, the number of underground distribution transformers installed in urban areas can be reduced to improve city aesthetics and reduce potential risks caused by transformer breakdown.

Description

Underground distribution transformer applying refrigeration cycle to chiller

Since the life of the transformer varies according to the degree of deterioration of the insulation wound around the transformer windings, the capacity related to the transformer allowable current may also depend on the method of removing heat applied to the transformer so that the winding insulation does not deteriorate. Underground distribution transformers (aka PAD transformers, inlet-cooled ground-mounted transformers) are installed in the distribution system. In particular, since distribution lines are constructed as underground lines in urban areas, underground distribution transformers are increasing in roadsides, green areas, and underground spaces. Increasing the number of underground distribution transformers can deteriorate the aesthetics of the city center and cause great damage to the surroundings in the event of a failure. The underground distribution transformer is installed at a place where many people come and go, and the space provided for installation is small, so that a large cooling fan cannot be used, and the cooling method adopts inflow cooling.

The present invention intends to apply the refrigeration cycle, which is the most effective cooling method in this short time, paying attention to the fact that the temperature is very short in the annual temperature duration curve of the transformer as shown in FIG. By using the refrigeration cycle can improve the cooling function to remove some of the radiator 21 installed inside the underground distribution transformer and eliminate the need for additional space by installing the condenser 33 and compressor 34 of the refrigeration cycle in this space. The turbine 71 is installed during the refrigeration cycle to add power or physical energy production functions in the generator (or mechanism) 72 connected to the turbine shaft.

1 is a perspective view of a conventional underground distribution transformer.

Figure 2 is an explanatory view of the arrangement of the radiator for cooling the existing underground distribution transformer. A plurality of radiators 21 are installed on the left and right sides and the rear side except the front of the transformer tank 22 to dissipate heat generated inside the transformer.

3 is a plan view of an underground distribution transformer in which a refrigeration cycle according to the present invention is additionally installed as a cooling device in an inflow cooling method. The top of the set of radiators 21 is removed, but the bottom is removed, and the condenser 33 and the compressor 34, which are important facilities of the refrigeration cycle, are disposed in this space. In order to prevent condenser heat from entering the underground distribution transformer, the condenser is kept in a separate space by using a heat insulator 37, and a cooling fan 35 is also added to the space for cooling the condenser. Ventilation holes 36 are installed in the underground distribution transformer enclosure 11 in the space where the condenser is installed to increase the cooling effect. The evaporator 31 is installed between the radiators 21 to maximize the cooling effect and the evaporators 31 connect the pipes to form a closed circuit as a whole. In the present invention, the refrigeration cycle is composed of a compressor 34, a condenser 33, an expansion valve (or capillary tube) 32, an evaporator 31, and a compressor 34 again. The compressor 34 compresses the gaseous refrigerant, and in the condenser 33, the compressed refrigerant dissipates heat to become liquid, and the liquid refrigerant becomes gaseous while passing through the expansion valve (or capillary tube) 32. It causes a change and the volume begins to expand. The refrigerant exiting the expansion valve (or capillary tube) 32 becomes gas while absorbing heat of vaporization from the radiator 21 around the evaporator 31 in the evaporator 31 connected to the expansion valve (or capillary tube) 32. The gas passing through the evaporator 31 enters the compressor 34 and is compressed to end one cycle of the refrigeration cycle. It is also included in the scope of the present invention to add a control device that senses the transformer winding temperature or the insulating oil temperature to smoothly operate the refrigeration cycle at the user's will.

4 is a right side view and a front view of a transformer in a battery employing a refrigeration cycle as a cooling device.

5 is an explanatory diagram of an underground distribution transformer adopting a refrigeration cycle as a cooling device and reinforcing the underground distribution transformer enclosure 11 with insulation. Since the temperature of the transformer is a problem during the summer, the solar heat flowing into the transformer through the underground distribution transformer enclosure 11 made of steel is also enormous. Since the refrigeration cycle will operate at a time when the transformer temperature is a problem, a method of reinforcing the inside of the underground distribution transformer enclosure 11 with the insulation 37 to increase the cooling effect of the refrigeration cycle is also included in the scope of the present invention.

6 is an explanatory diagram of an underground distribution transformer in which a refrigeration cycle other than the evaporator 31 is installed outside the transformer. It is also included in the scope of the present invention to install some equipment of the refrigeration cycle by securing a space on a part of the side as well as the upper part.

7 is an explanatory view of a refrigeration cycle. The regenerative generation refrigeration cycle in addition to the normal refrigeration cycle inserts a turbine 71 between the evaporator 31 and the compressor 34. The generator (or machine) 72 is installed in the turbine 71 shaft. As the refrigerant vaporizes in the evaporator 31 and flows into the compressor 34, the turbine 71 is rotated and power or physical energy is produced by a generator (or a mechanical device) connected to the shaft of the turbine 71. The electric power thus produced is used as an internal device of the underground distribution transformer, in particular, the cooling fan 35 as an independent power source or as a compressor power source through a parallel operation assistance device, or a fan is installed on the shaft of the turbine 71 to provide a cooling fan 35. Direct use is also included in the scope of the present invention.

8 is an explanatory diagram of a temperature curve of a year of a transformer. Even if we plot the temperature increase of 30% and 50% in the normal operating temperature curve, it can be seen that the time for which temperature is a problem and the area requiring cooling are very small. If the transformer capacity is limited by this small amount of time, the cooling unit with refrigeration cycle is effective for increasing the transformer capacity.

By cooling the heat applied to the underground distribution transformer using the refrigerant vaporization heat by the refrigeration cycle, the heat inside the transformer can be effectively cooled to increase the capacity of the transformer and increase efficiency. In particular, as shown in the annual temperature continuity curve, the transformer temperature problem is only a short time of year. If only a cooling system using an effective refrigeration cycle is employed during this time, the number of transformers to be installed can be reduced. It can improve aesthetics and drastically reduce investment costs.

1 is a perspective view of a conventional underground distribution transformer.

Figure 2 is an explanatory view of a conventional radiator for cooling the underground distribution transformer.

3 is a plan view of an underground distribution transformer employing a refrigeration cycle as a cooling device.

4 is a right side view and a front view of an underground distribution transformer employing a refrigeration cycle as a cooling device.

5 is an explanatory view of the insulation reinforcement underground distribution transformer employing a refrigeration cycle as a cooling device.

6 is an explanatory diagram of an underground distribution transformer in which a refrigeration cycle other than an evaporator is installed outside a transformer.

7 is an explanatory view of a refrigeration cycle.

8 is an explanatory diagram of a transformer annual temperature sustain curve.

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

11: underground distribution transformer enclosure 12: vent

13: enclosure 21: radiator

22: transformer tank 31: evaporator

32: expansion valve (or capillary) 33: condenser

34 compressor 35 cooling fan

36: vent 37: insulation

71: turbine 72: generator (or mechanism)

Claims (1)

An evaporator 31 installed between the underground distribution transformer and the internal radiator 21; Evaporator (31), compressor (34), condenser (33), expansion valve (or capillary tube) 32, in order to be circulated back to the evaporator (31) and connected to the pipe is installed inside the underground distribution transformer enclosure (11) A refrigeration cycle; Underground distribution transformer applying a refrigeration cycle to the cooling device characterized by the insulation (37).