Box-type substation is a kind of high-voltage switchgear, power distribution transformer and low-voltage power distribution device. It is a factory-prefabricated indoor and outdoor compact power distribution device that is integrated into a whole according to a certain wiring scheme. Electricity and other functions are organically combined and installed in a moisture-proof, rust-proof, dust-proof, rodent-proof, fire-proof, burglar-proof, heat-insulated, fully-enclosed, movable steel structure box, with mechanical and electrical integration and fully enclosed operation. Applicable to urban network construction and transformation, it is a brand new substation that rises after civil substations.

Another box-type substation (referred to as a box-type transformer) is a compact complete set of high-voltage switchgear distribution transformers, low-voltage switchgear, electrical energy measurement equipment, and reactive power compensation devices in one or more boxes according to a certain wiring scheme. Power distribution device. It is suitable for three-phase AC systems with a rated voltage of 10 / 0.4KV, and is used for line and power distribution. Suitable for factories, mines, oil fields, ports, airports, urban public buildings, residential quarters, highways, underground facilities and other places.

According to different product structures and different components, it is divided into two typical styles: European box transformer and American box transformer.

Since the late 1970s, China has introduced and imitated box-type substations from France, Germany and other countries. The structure uses high- and low-voltage switchgears and transformers. This box-type transformer is called a European-style box-type transformer. Low-voltage switchgear and transformers covered the house.

Since the 1990s, China has introduced American box-type substations, and simplified the structure of load switches, ring network switches and fuses into transformer oil tanks immersed in oil. The arrester also uses an oil-immersed zinc oxide arrester. The oil pillow is removed from the transformer, and the fuel tank and radiator are exposed to the air. This type of box change is called an American box change, and the image is likened to a box hanging next to the transformer.

From the perspective of volume, the European-style box transformer has a larger volume due to the internal installation of conventional switch cabinets and transformers. The American box transformer has a smaller installation volume due to the integrated installation.

From the protection aspect, the high-voltage side of the European-style box transformer is protected by a load switch and a current-limiting fuse. When a one-phase fuse is blown, use the fuse's striker to open the three phases of the load switch at the same time to avoid lack of phase operation. The load switch is required to have the ability to cut off the transfer current. The low-voltage side adopts load switch and current-limiting fuse protection, and the American box transformer high-voltage side adopts fuse protection. The load switch only has the function of switching, switching and cutting off the high-voltage load current, and the capacity is small. When a phase fuse is blown on the high-voltage side, the voltage on the low-voltage side is reduced, and the plastic case automatic air switch will operate under-voltage protection or over-current protection, and low-voltage operation will not occur.

From the perspective of product cost, European-style boxes have become expensive. From the perspective of product price reduction, the American box transformer still has a large price reduction space. On the one hand, the three-phase five-column iron core of the American box transformer can be changed to three-phase three-column iron core; on the other hand, the high-voltage part of the American box transformer can be modified from The transformer oil tank is moved to the outside of the fuel tank, occupying the space of the high voltage room.

Box change model

Pre-installed (combined, box type) substation

1 6 (10) /0.4 (0.7) kV pre-installed (combined, box type) substation

2 Mine combination (box type) substation

3 6 (10) /0.4kV pre-installed (combined, box type) substation

4 35/6 (10) kV combined (box type) substation

Box-type substation features

The box-type substation has a small footprint. The general box-type substation covers an area of only 5 ~ 6㎡, which can even reduce 3 ~ 3.5㎡. It is suitable for places such as general load-intensive industrial and mining enterprises, ports and residential residential areas, which can extend high-voltage power supply to the load center, reduce the radius of low-voltage power supply, and reduce losses. There are fewer low-voltage power supply lines, generally 4 ~ 6. Shorten site construction cycle and less investment. When new equipment such as hermetically sealed transformers and SF6 switch cabinets are used, the equipment maintenance period can be extended, and even maintenance-free requirements can be achieved. The appearance is novel and beautiful, which can coordinate with the environment around the substation.