A box-type substation, also known as a prefabricated substation or pre-assembled substation, is a comprehensive power distribution unit incorporating high-voltage switchgear, distribution transformers, and low-voltage distribution devices. Box-type substations find applications in mining, industrial enterprises, oil and gas fields, and wind power stations. They have replaced traditional civil-built distribution rooms and substations, emerging as a novel integrated power distribution solution.
In recent years, the increasing load density for low-voltage power supply has raised stringent requirements for the reliability and quality of power delivery. In such circumstances, if a large-capacity substation serves as the central point supplying power to surrounding users at low voltage, it would consume a significant amount of non-ferrous metals, resulting in substantial energy losses and an inability to guarantee power supply quality. Conversely, establishing substations at high voltage points within the load center can reduce the radius of low-voltage power supply, enhance power supply quality, save non-ferrous metals, and reduce energy losses. Box-type substations are particularly suitable for construction at load centers.
High-voltage/low-voltage prefabricated box-type substations, also referred to as box-type substations, generally feature a box-like structure with compartments for high-voltage switchgear, transformer, and low-voltage distribution switchgear. They operate at rated voltages of 10kV and 35kV, accommodating transformers up to 1600kVA. Key characteristics include a small footprint, rapid construction, aesthetic appearance, adaptability, low maintenance requirements, and cost-effectiveness.
As a result, box-type substations have gained attention and popularity both domestically and internationally, presenting a promising future in the field of electrical equipment. They have been widely deployed in factories, mines, oil fields, ports, airports, stations, public buildings, residential areas, government offices, schools, commercial halls, and underground facilities.
Currently, various models of combined substations are available domestically, including outdoor, indoor, fully enclosed, semi-enclosed, with or without corridors, combined, fixed, and device-type substations. They can accommodate dry-type or oil-immersed transformers and offer terminal or loop power supply options, meeting diverse user needs.
The layout of the high-voltage, transformer, and low-voltage compartments follows a "T" or "H" shape arrangement. High-voltage compartments utilize domestically produced or imported ring main units, load switches with current-limiting fuses, and vacuum circuit breakers. The low-voltage compartment comprises power, lighting, metering, and reactive power compensation cabinets. Ventilation and heat dissipation include fans, temperature automatic controllers, and anti-condensation controllers.
The enclosure is mostly constructed from ordinary or hot-dip galvanized steel plates, and aluminum alloy plates, with the framework welded or bolted together using shaped steel.