1. American box change:

1) The wiring form of the box-transformer One or two 10KV incoming lines; the capacity of a single transformer is generally 500KVA~800KVA; the low-voltage outgoing cables are 4~6 lines.

2) The main components of the box change are composed of transformer, 10KV ring network switch, 10KV cable plug, low-voltage pile head box and other main components. It has the advantages of small size, low cost and easy installation. Advantages and disadvantages of American box change

3) Advantages: small size, small footprint, easy placement, easy camouflage, and easy coordination with the environment of the community. It can shorten the length of low-voltage cables, reduce line loss, and reduce the cost of power supply.

4) Disadvantages: low reliability of power supply; no electric mechanism, no power distribution automation device; no capacitor device, which is not good for reducing line loss; noise is higher than that of type III and type V stations, because type III and type V stations It is to place the transformer indoors to play the role of sound insulation; in addition, the concentrated electromagnetic radiation of the type III and type V stations is decomposed into multi-point radiation; due to the different civil foundations of the box transformer with different capacities, the capacity of the box transformer is increased. Inconvenient; when the box becomes overloaded or the user increases the capacity, the civil construction needs to be rebuilt, and there will be a long blackout time, which increases the difficulty of the project.

2. European box change:

1) The wiring form of the box change

a. Single distribution variant—two 10KV incoming lines; the capacity of a single transformer is generally 500KVA~800KVA; the low-voltage outgoing cables are generally 4~6 lines.

b. Two distribution variants - two 10KV incoming lines; two transformers, each with a capacity of 500KVA~800KKVA; low-voltage outgoing cables are generally 8~12 lines.

2) The main components of the box change It is composed of transformers, 10KV ring network switchgear, low-voltage capacitors, low-voltage switches and other main components, which is equivalent to compactly installing the equipment of the type III station in a metal box, making the type III station miniaturized. The volume of the European-style box is higher and larger than that of the American-style box, and the cost is also higher than that of the American-style box.

3) Advantages: The noise is comparable to that of Type III and Type I stations; the radiation is lower than that of the American box-type transformer, because the transformer of the European-type box-type transformer is placed in a metal box to play a shielding role; power distribution automation can be set up, which not only has the The advantages of type III station and type I station, but also the main advantages of American box transformer.

4) Disadvantages: The volume is large, which is not conducive to installation, and has a certain impact on the environmental layout of the community;

two

Due to the different structure of the box change, the place of use is also different, and the power supply network is also different.

Because the structure of the American-style box-type transformer and the European-style box-type transformer are different in reliability, the applicable occasions are also different. When the capacity of the American box transformer is selected to be smaller and the building area of the community is larger, the applied box transformer will increase a lot, so that the load points connected to the overhead line will increase; when reducing the support load point of the overhead line It is necessary to increase the number of series connection of the box change, so that the network structure is weak. To overcome the problem of weak network structure caused by the small-capacity box change, it is best to use the ring site to solve it.

Applicable places for American box change

In view of the structural characteristics and advantages and disadvantages of American box transformers, American box transformers are suitable for the electricity consumption of multi-storey houses and other unimportant buildings with relatively low power supply requirements. According to our actual use situation, after the American box transformer is equipped with a small ring network switch station, it is fully suitable for the power supply demand of multi-storey residential buildings. Because the box transformer fails, it has little impact on residents, but it is not suitable for small high-rise and high-rise buildings.

The applicable place of European box change

European-style box transformers are suitable for multi-storey residences, small high-rises, high-rises and other more important buildings.