Substation Structure is to contact the user of the intermediate links and transformation and Power plants distribution of electric energy plays a role. Classification of substation the following categories: 1. In accordance with the status and role of substations in the power system can be divided (1) the system hub substation. Hub substation is located in the hub points in the power system, its voltage is the system the highest transmission voltage, the current voltage level has 220kv, 330kV (Northwest power grid only) and 500kv, hub substation connected into the ring, after the station blackout, it will cause the system splitting and even paralysis of the entire system, so the hub substation high reliability requirements of. Hub substation main transformer capacity, wide supply range. (2) regional primary stations. Area substation is located in a hub point area network, is the main network and transmission areas receiving end substation connected, the task is directly affected by the power from the main grid, power supply to this area. Full stop after power failure, which can cause the collapse of the regional power grid, power supply affects the entire region. Voltage level commonly used 220kv or 330kv. A large area substation main transformer capacity, the number of outgoing circuit more, the reliability of the power supply requirements are relatively high. (3) regional secondary substation. Region by the regional primary substation secondary substation by power directly to the load power supply in the region, small power range, the main transformer capacity and the number of units according to the power load may be. After the station blackout, only interrupt the power supply in the region. (4) Terminal Substation. Terminal substation transmission line terminal, close to the load point, the power supply directly to the user via the buck, after station blackout, but the end-user power outages. 2. Divided according to the substation installation location (1) outdoor substation. In addition to the outdoor substation control and DC power supply and other equipment on the indoor and outdoor, transformers, circuit breakers, disconnectors and other major equipment are arranged in the outdoors. This substation construction area of small, low construction cost, high voltage substations generally use outdoor settings. (2) indoor substation. Indoor substation major equipment are on the interior, reducing the total area, but higher construction costs, suitable for densely populated urban areas, or on the coast, Salt Lake, chemical plants and other high air pollution class areas. (3) underground substation. In highly concentrated population and industrial cities, due to urban electricity capacity, built-up, will be provided at the substation underground cities large buildings, roads, parks, and can reduce the area, especially with the development of urban power grids, large hub substation and the substation is located in the city will take more underground substation. This substation majority of unmanned substation. (4) box-type substation. Box-type substation, also known as prefabricated substation is to transformers, high-voltage switchgear, low-voltage electrical equipment and connections and auxiliary equipment is compact combination with each other, according to the different main wiring and components, arranged in a certain way concentrated in one or several closed tank shell. Box-type substation is designed and manufactured by the factory, compact structure, small footprint, high reliability, easy installation, now widely used in residential areas and parks. Box-type substation capacity is not general, voltage level is generally 3kv ~ 35kv, with the improvement and development of the grid required voltage range continues to expand, now it has produced the box-type substation of 132kv. Box-type substation installed in accordance with the different positions can be divided into two types of indoors and outdoors.
