The box-type substation generally adopts the structure that each unit is independent of each other, with transformer room, high-voltage switching room and low-voltage switching room respectively, which are connected to a complete power supply system through wires.
The transformer room is generally placed at the back. In order to facilitate the user's maintenance, replacement and capacity increase needs, the transformer can be easily pulled out of the box or lifted from the upper part.
Because the transformer is placed in the shell, its favorable factors is to prevent direct sunlight on the transformer and the temperature rise, but also can effectively prevent the external collision, impact and the occurrence of touch-sensitive electrical accidents; the disadvantage is that the transformer's heat dissipation puts forward a high demand.
High-voltage switch room is installed with independent closed high-voltage switchgear, cabinet is generally installed with gas production, compressed air or vacuum load switch - fuse combination of electrical appliances, which is installed on the high-voltage fuses to ensure that any phase of the fuse can be made to make any phase fuse breaks the main switch, in order to avoid the lack of phase operation.
In addition, there is also a grounding switch, which is interlocked with the main switch, i.e., only after separating the main switch, the grounding switch can be closed, and after closing the grounding switch, the main switch can not be turned off, so as to ensure the safety of maintenance.
Expanded
The box-type substation due to the compact structure, each box constitute an independent system, which makes the combination of flexible, on the one hand, can be used in all the box, that is to say, the 35kv and 10kv equipment are all installed in the box, composed of the whole box-type substation.
On the other hand, only 10kv switch box can be used, 35kv equipment installed outdoors, 10kv equipment and control and protection system installed in the box, for this combination of ways, especially suitable for the transformation of agricultural networks in the transformation of the old station, that is, the original 35kv equipment does not move, and only the installation of a 10kv switch box can be achieved to achieve the requirements of the unattended.
In short, there is no fixed combination of box-type substation mode, the use of units can be based on the actual situation of free combination of some modes to meet the needs of safe operation.
The shell of the box-type substation is made of steel plate or alloy plate, equipped with double-layer top cover and good heat insulation. The shell and skeleton are all anticorrosive treated, with long-term outdoor use conditions. The shape and color can be coordinated with the environment.
Easy to install, there is a cable room under the foundation of the box-type substation, and there is a manhole in the low-voltage room to enter the cable room for work. From the volume point of view, the European box variable due to the internal installation of conventional switchgear and transformers, the product volume is larger. American box variable due to the use of integrated installation volume is smaller.
Baidu Encyclopedia - Box-type substation