Product Introduction: QHB series ring main unit is a SF6 gas insulated metal-enclosed switchgear that is developed and produced independently by our company. It takes SF6 gas as medium for insulation and switching, and the load switch, the vacuum circuit breaker and the live busbar of the unit are all sealed in an enclosed stainless steel container under certain pressure. Casings of American-standard/EU standard are used for connecting inlet and outlet cables by cable joints, so as to form a full insulated and enclosed structure for effective resistance to flood and staining. It is suitable for different severe environments, and is widely applied to 12KV ring net or terminal power supply systems.   Product Features a.Maintenance-free In the SF6 gas-insulated common tank structure, moving and fixed contacts, arc extinguish chamber and busbar are sealed in a gas tank. With the design, it is free from maintenance about 30 years. b.Reliable mechanical interlocking It is provided with various types of reliable mechanical interlocking, as well as simulation marks on the panel of cubicle to guarantee safety of operation. c.Full-sealed and full-insulated inlet and outlet cables The full-sealed and full-insulated cable joints are used according to user demands, and the function of live displaying can accurately indicate the charged condition of each loop. d.Modular and extendable By the combination mode of extended modules, one gas tank can be combined by 5 modules at most, or be extended through busbar for more modules. The busbar for extension is of a full-insulated and full-shielded structure to protect it from weather condition influence and to guarantee maintenance-free completely. e.Diversified wiring schemes The optimal combining schemes such as load switch, load switch plus fuse protection or protection of vacuum circuit breaker are adopted according to user demands, so as to meet different requirements on incoming and outgoing circuits. f.Visible fracture The fracture of load switch or position of earthing switch can be observed through the inspection window on the panel, which can fully guarantee safety of personnel and equipment. g.Electric operation, FTU A special voltage transformer is employed to provide power and measurement protection voltage signal for operating mechanism and FTU. Furthermore, special-use batteries and charger module are installed to ensure uninterrupted power supply of operational power supply and FTU. It requires a corresponding FTU according to user needs.   Typical schemes R module- spatial lattice (cable lifting) L module-load switch type F module- load switch + fuse protection type V module- vacuum circuit breaker type  Technical Parameters   Service Conditions: Ambient air temperature -40°C~+40°C, the mean value measured in 24h shall not exceed 35°C; Altitude no more than 2000m; The pollution of dust, smoke, corrosion and (or) inflammable gas, steam or salt in the ambient air is not serious; The pollution of dust, smoke, corrosion and (or) inflammable gas, steam or salt in the ambient air is not serious;