(1) The steel with higher mechanical strength (e.g. boiler steel) should be selected as far as possible for GIS shell under operating impact; (2) the eddy current loss of bus barrel with three-phase common box is smaller than that of single-phase bus barrel; (3) the welding performance of steel shell is better than that of aluminum shell; (4) the air tightness of cast aluminum shell is more difficult to control; (5) the design and fabrication of aluminum shell Generally,and the cost is about 20% higher than that of the same function steel (or tailor welded stainless steel) shell.

The dynamic sealing surface can be divided into rotating sealing surface and sliding sealing surface according to the action property. The rotating sealing surface is located on the transmission arm of the disconnector and the grounding knife gate. The rotating range of the sealing gasket on this kind of sealing surface is about 76 degrees. Three O-type sealing gaskets are used to strengthen the sealing. Seen from the situation of leakage detection in site installation,and its sealing effect is satisfactory, but with the passage of time, the increase of operation times and the aging of rubber, the sealing condition of this kind of sealing surface needs to be noticed, especially the gasket on the disconnector or grounding knife gate with more operation times. The sliding sealing surface is located on the operating pull rod of the circuit breaker. Its sealing gasket section is "V" type, and the sealing surface is metal rod surface. It has four smooth "V" type sealing rings.And the sealing is quite reliable and is not easy to leak.

There are many problems found when static sealing surface is installed and leaked on site.And there are two main reasons for leakage of static sealing surface: defect of sealing gasket itself and bad combination of sealing surface.