High pressure RMU is to improve the reliability of power supply, so that users can get the power from two directions, usually for grid connected in a ring. This referred to as the power supply ring network. In the industrial and mining enterprises, residential quarters, ports and high-rise buildings and other AC 10KV distribution system, not due to load capacity, its high voltage circuit usually vacuum load switch or contactor control, and is equipped with high-voltage fuse protection. The system typically uses a ring network power supply, called the High Voltage Switchgear RMU general use habits. RMU except the power to this distribution, its high-voltage bus also through endless supply current through the grid (ie by this substation to substation power bus current neighbor), so RMU high voltage bus To cross-section according to the distribution of the load current in the ring currents chosen to ensure that the operation of the high voltage bus but load operation. Currently RMU many types of products, such as HK-10, MKH-10,8DH-10, XGN-15 and SM6 series. RMU is a group of high-voltage switchgear cabinet mounted on a metal plate or made of assembled interval-type ring network power supply unit of the electrical equipment, the core part of the load switch and fuse, has a simple structure, small size, low price, can be improve power supply parameters and performance as well as power supply and safety. It is widely used in power distribution stations and box-type substation in urban residential area, high-rise buildings, large public buildings, factories and enterprises and other load centers. RMU is generally divided into two kinds of air-insulated SF6 insulated for the division and load current, breaking short-circuit current and the transformer load current, a certain distance overhead lines, cable lines charging current from the control and protection, a ring Important network power supply and terminal power supply switching equipment. Cabinet with air-insulated load switch main gas type, gas pressure type, vacuum type, with SF6 insulation is SF6 load switch type, since the SF6 gas is sealed within the housing, cut off the formation of fracture it is not visible. RMU in the load switch, generally require three-position, to cut off load isolation circuit by grounding feasible. Gas type, air pressure-load switch and SF6 three-position easy to achieve, and only breaking the vacuum interrupter is not isolated, it is generally ring network switchgear vacuum load before the load switch plus an isolation switch to forming an isolation fracture.