Solid-insulated ring main units (RMUs) have not been around for a long time, but they have been widely used in recent years. This is mainly because, from the perspective of power supply and distribution, most of the buildings of newly developed industrial enterprises and public institutions have medium and small capacities—their distribution transformers generally do not exceed 1250 kVA, requiring long-term stable power supply and infrequent operation of high-voltage switches.
For such users, although the performance of solid-insulated RMUs is not perfect, it is sufficient and competent. With large-scale urban construction, a large number of large high-rise buildings have sprung up, and power transformation and distribution stations are often located downstairs. According to fire safety requirements, power transformation and distribution equipment must be "oil-free"; in terms of the rational use of construction area, such equipment should be "miniaturized". Thus, solid-insulated RMUs (or vacuum circuit breakers), dry-type transformers, and dry-type transformers have been installed in numerous buildings.
Solid-insulated RMUs feature a simple structure, reliable and safe operation, minimal maintenance, and low operating costs. Compared with switchgear equipped with circuit breakers, they have distinct advantages. Solid-insulated RMUs require load switches with higher performance and smaller size, prompting the emergence of new-type load switches. This, in turn, has driven technological progress in solid-insulated RMUs. Today's solid-insulated RMUs not only have excellent performance but also are serialized, which has further expanded their scope of application.
This article is edited and organized by DAYA Electric Group Co., Ltd. (https://www.hygraphics.com/). Please indicate the source when reprinting.