Box-type substations are suitable for applications such as residential complexes, urban public utility power supply, bustling commercial districts, and construction site power sources; users can select the appropriate unit based on specific operating conditions and load requirements. Since their inception, box-type substations have seen rapid adoption, accounting for 70% of distribution transformers in developed European nations and 90% in the United States. Driven by China's rapid urban modernization and the continuous upgrading of urban distribution networks, these substations are poised for widespread application in the country.
Regarding the evolution of these units in China: starting in the late 1970s, the country introduced and replicated designs from nations like France and Germany. These units-structurally composed of high-voltage switchgear, low-voltage switchgear, and a transformer-are known as "European-style" box substations; they can be visualized as a housing structure built to enclose the switchgear and transformer. Beginning in the 1990s, China introduced American-style box substations. Structurally, components such as load switches, ring main unit switches, and fuses were simplified and submerged directly within the transformer's oil tank; oil-immersed zinc oxide arresters were also employed. These units eliminated the oil conservator, leaving the tank and radiators exposed to the air; this design is known as the "American-style" box substation, which can be visualized as a box attached to the side of the transformer.