CN201285685Y - Ground buried type distribution transformer - Google Patents

Abstract

The utility model discloses a buried distribution transformer which comprises a transformer case and a case cover, wherein a low-voltage leading-out device, a high-voltage leading-out device and a high-voltage protection device are arranged on the case cover; and a device body enclosed by insulating liquid is arranged in the transformer case. The buried distribution transformer improves the heat-resistant level without installing any ventilator, does not have any effect on the surroundings, shorts the construction period of a pit and simplifies the construction steps of the pit.

Description

Buried distribution transformer

technical field

The utility model relates to a distribution transformer, in particular to an underground distribution transformer.

Background technique

Buried distribution transformers are playing an increasingly important role in the development of urban power grids, especially in the landscaped streets of big cities, where power distribution equipment goes underground is becoming a trend in urban development. At present, the buried distribution transformers produced in China are generally installed in the pre-cast pits, and the corresponding ventilation and heat dissipation facilities are used to ensure that the temperature rise of the buried distribution transformers will not be too high. Therefore, the safe operation of buried distribution transformers depends to a large extent on the quality of the pits and heat dissipation facilities, and the domestic construction teams are uneven, and there are always some large and small pits more or less. Hidden danger. Such hidden dangers affect the safe operation of transformers to a large extent, so a key issue of buried distribution transformers is the design of temperature rise. The existing buried distribution transformers are all oil-immersed transformers, that is, the transformer body is immersed in oil. The oil used is traditional transformer oil. The heat resistance grade of traditional transformer oil is A grade, that is, the highest point temperature It cannot exceed 120 degrees. If it exceeds this temperature, the insulation performance of the oil will be greatly reduced, which will affect the safety of the product. If the design of the transformer is considered from the perspective of traditional transformer oil, the temperature rise design can be improved to properly alleviate the hidden dangers of ventilation and heat dissipation, but the volume of the transformer itself will increase with the increase in materials used, so the buried distribution transformer The cost of the product itself will be greatly increased. However, adding ventilation and heat dissipation facilities in the pit not only consumes the construction period, but also forces the pit to occupy a considerable area. The ventilation pipes must protrude from the ground, and related devices must be installed on the ground, which will have a certain impact on the surrounding environment. , and once the relevant ventilation and heat dissipation devices are damaged, it will also cause potential safety hazards for the transformer. Moreover, the water level in southern my country is low and humid, and the current situation of installing transformers underground requires prefabricated cement pits to be buried, and the accident rate of imported foreign buried transformers is high, which is not suitable for the domestic working environment.

Utility model content

The purpose of this utility model is to provide a buried distribution transformer in order to overcome the shortcomings of the prior art transformers such as long construction period and high accident rate. The buried distribution transformer has improved its heat resistance level and does not require installation Any ventilation device does not affect the surrounding environment at all, shortens the construction period of the pit, simplifies the construction steps of the pit, and can operate reliably under long-term water immersion.

The utility model achieves the above-mentioned purpose through the following technical scheme: a buried distribution transformer, its substantive feature is that it includes a transformer box and a box cover, and the box cover is provided with a low-voltage outlet device, A high-voltage outlet device and a high-voltage protection device, the transformer box is provided with a body surrounded by insulating fluid.

Wherein, the low-voltage outlet device, the high-voltage outlet device and the high-voltage protection device are respectively located on three sides of the box cover.

Wherein, the transformer box body and the box cover are welded.

Among them, the transformer box is surrounded by plate radiators.

Wherein, the low-voltage outlet device is a cable joint spiral structure.

Wherein, the high-voltage outlet device is a cable plug-in structure.

Wherein, the high-voltage protection device includes a protection fuse and an oil-immersed high-voltage load switch.

The positive and progressive effect of the utility model is that the utility model is used in the field of buried distribution transformers. After using this device, the buried distribution transformers do not need ventilation equipment on the ground, and the buried distribution transformers are removed from the pit. There is no need for other equipment other than this device to reduce the volume of the original liquid-immersed oil-immersed underground transformer. The construction requirements of the pit are low, and the body of the buried distribution transformer can transfer heat to the surrounding ground through this heat sink to meet the The temperature rise requirements of the buried distribution transformer in normal operation are met, and there is no ventilation device at the same time, that is, its high temperature resistance is improved, so as to cancel or reduce the ventilation and heat dissipation facilities of the pit, reduce the cost, and do not affect the surrounding area at all. environment; moreover, after the cable is laid in place, it only needs to dig a hole, bury it and wire it, which greatly shortens the construction period of the pit.

Description of drawings

Fig. 1 is a schematic diagram of an embodiment of the utility model.

FIG. 2 is a top view of FIG. 1 .

Detailed ways

A preferred embodiment is given below, and the utility model is described more clearly and completely in conjunction with the accompanying drawings.

Fig. 1 is a schematic diagram of an embodiment of the utility model. As shown in Figure 1, the utility model includes a transformer box 1 and a box cover 3, the transformer box 1 and the box cover 3 are welded to form a sealed structure, and the box cover 3 is provided with a low voltage Outlet device 2, a high-voltage outlet device 4 and a high-voltage protection device 5, the low-voltage outlet device 2, high-voltage outlet device 4 and high-voltage protection device 5 are respectively located on three sides of the box cover 3, the transformer box 1 is provided with an insulated Body 6 surrounded by liquid, the insulating liquid is a mixture of Class H and Class F insulating liquids.

Among them, the transformer box 1 is made of metal material with strong corrosion resistance and rust resistance, and plate radiators are installed around it to increase the heat radiation effect. The low-voltage outlet device 2 is a spiral structure of cable joints, considering the diversity of users, it can realize 1-3 outlets, and can reduce the number of low-voltage cable branch boxes. The high-voltage outlet device 4 is a cable plug-in structure, and all joints are protected by sealing accessories, which are matched with high-voltage cables and equipped with accessory supports. The high-voltage protection device 5 is composed of two parts, one is a full-range protection fuse, and the other is an oil-immersed high-voltage load switch, and they work together to complete the protection of the high-voltage side of the transformer. The insulation design of the body 6 adopts the new liquid-immersed design principle of Class B insulation, which is obviously different from the traditional oil-immersed distribution transformer design structure in terms of coil and body insulation structure: according to the electrical properties of the selected insulating materials and In terms of mechanical properties, the following principles are adopted in the design: ①The minimum oil passage width is specified; ②The span of each step of the stay curtain is appropriately increased; ③On the premise of meeting the insulation distance, the number of oil passages is reduced; ④The oil guide can be increased measure. Like this, above-mentioned part and transformer body 6 and insulating liquid have constituted a liquid-immersed combined underground distribution transformer with high-voltage band protection and low-voltage band shunt.

The utility model underground transformer has the following differences from the traditional underground transformer in terms of structure:

(1) Iron core: core-type three-phase five-column amorphous alloy iron core structure is adopted to reduce underground variable height

(2) Winding: The high-voltage winding adopts a cylindrical structure, and the wire uses a new type of acetal enamelled copper wire QQ-2

155, insulation heat resistance grade is F grade, low voltage adopts foil structure, epoxy natural curing technology, insulation heat resistance grade is F grade.

(3) Body insulation: The insulation parts of the body adopt H and F grade mixed insulation, and carry out vacuum drying and vacuum impregnation.

(4) Fuel tank and accessories: The fuel tank is a rectangular fully sealed structure with a flat heat sink and stainless steel material.

(5) When the cable connector used in the high-voltage incoming line is installed, an elbow compression device is installed, and a sealed waterproof sleeve is installed outside the high-voltage bushing.

(6) The high-voltage load switch adopts an extended double-channel sealed three-phase AC oil-immersed load switch.

(7) The tap-changer adopts an extended double-channel sealed non-excitation tap-changer.

(8) The high-voltage side adopts a current-limiting full-range protection fuse for short-circuit and overload protection of the transformer.

(9) The low-voltage side adopts a special cable connector with an insulating waterproof sleeve.

The utility model is used in the field of buried distribution transformers. After using this device, the buried distribution transformer does not need ventilation equipment on the ground, and no other equipment is needed in the pit except the buried distribution transformer and this device, so as to The volume of the original liquid-immersed oil-immersed underground transformer is reduced, and the construction requirements of the pit are low. The body of the buried distribution transformer can transfer heat to the surrounding ground through this cooling device, which meets the normal operation of the buried distribution transformer. At the same time, there is no ventilation device, which means that its high temperature resistance is improved, so as to cancel or reduce the ventilation and heat dissipation facilities of the pit, reduce the cost, do not affect the surrounding environment at all, and greatly shorten the construction of the pit. cycle. Moreover, underground transformers imported from abroad are only allowed to operate in water for a certain period of time, and tunnel construction is required during installation. The protection level of the transformer of the utility model reaches IP68, and it can operate safely in sewage for a long time, and can be installed in places where other traditional distribution transformers cannot be installed. Low water level, wet and rainy geographical characteristics.

Although the specific embodiments of the present utility model have been described above, those skilled in the art should understand that these are only examples, and various modifications can be made to these embodiments without departing from the principle and essence of the present utility model. change or modification. Therefore, the protection scope of the present utility model is defined by the appended claims.

Claims (7)

1. An underground distribution transformer, characterized in that it includes a transformer box and a box cover, and the box cover is provided with a low-voltage outlet device, a high-voltage outlet device and a high-voltage protection device, the transformer box There is a body surrounded by insulating fluid inside. 2. The buried distribution transformer according to claim 1, characterized in that the low-voltage outlet device, the high-voltage outlet device and the high-voltage protection device are respectively located on three sides of the box cover. 3. The buried distribution transformer according to claim 1, characterized in that the transformer box and the box cover are welded. 4. The buried distribution transformer according to claim 1, characterized in that, the transformer box is surrounded by plate radiators. 5. The buried distribution transformer according to claim 1, characterized in that the low-voltage outlet device is a cable joint spiral structure. 6. The buried distribution transformer according to claim 1, characterized in that the high-voltage outlet device is a cable plug-in structure. 7. The buried distribution transformer according to claim 1, wherein the high voltage protection device comprises a protective fuse and an oil-immersed high voltage load switch.

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