As the name suggests, a solid insulated ring main unit (RMU) is a type of ring main unit that uses solid insulating materials as the main insulation medium. It encapsulates the vacuum interrupter, its conductive connections, isolating switch, earthing switch, main busbar, and other main conductive circuits (either individually or in combination) with a solid insulation medium into one or more fully insulated and hermetically sealed modules that have specific functions and can be recombined and expanded. The touchable surfaces are coated with a conductive or semi-conductive shielding layer and can be directly and reliably grounded.
Its structural design is based on meeting and adapting to the requirements of modern strong smart grids, featuring key characteristics such as full insulation, full sealing, modularization, and miniaturization. The main circuit part adopts a single-phase module design: on one hand, it can completely avoid the occurrence of phase-to-phase short-circuit faults during operation; on the other hand, it greatly improves maintenance efficiency while reducing maintenance costs.
In terms of principle and structure, it completely eliminates SF₆ gas and corresponding gas tank components, thoroughly solving accidents caused by explosions due to pressure rise when internal switches of the gas tank are short-circuited. It also fully avoids the emission of harmful gases resulting from the decomposition and leakage of SF₆ gas, truly becoming an environmentally friendly switch product needed by society.
Furthermore, solid insulated RMUs have more prominent resistance to harsh environments compared with SF₆ RMUs, with stronger and more obvious adaptability in harsh conditions such as extreme cold, plateaus, humidity, and strong sandstorms. At the same time, solid insulated RMUs are equipped with online monitoring functions for insulation, temperature rise, mechanical characteristics, etc., to meet the requirements of domestic strong smart grids.
This article is compiled and edited by DAYA Electric Group Co., Ltd. (https://www.hygraphics.com/). Please indicate the source when reprinting.