VSR3-12/D630A series vacuum ring main unit is a 12kV fully enclosed and insulated switch cabinet produced by Zhuhai XJ Electric Co., Ltd. It adopts vacuum as the arc extinction medium, uses SF6 gas as the insulating medium and is applicable to neutral point earthing system via small resistance, neutral point ungrounded system and neutral point earthing system via an arc suppression coil for 10kV cable network and elevated cable hybrid network.

All live parts of vacuum switches of this cabinet and the switches are enclosed in a stainless steel gas chamber. The enclosed chamber is filled with the SF6 gas. SF6 gas is a colorless and odorless inert gas without any impact on the environment. Its dielectric strength is three times that of air and it is not decomposed even at 500℃. Before leaving the factory, the switch cabinet is filled with SF6 gas at the specified pressure. The rated gas pressure is ‘0’MPa. The cabinet may be configured flexibly. Multiple cabinet types and combination schemes are available. There is either manual mechanism or motor-driven mechanism. Their overall and installation dimensions are similar. The cabinet may be installed outdoor or indoor, including in basement, concrete box and stainless steel box.