The fully enclosed combined electrical room represents a complex spatial configuration where equipment

pipelines and cabinets coexist.SF6 gas leakage within such an environment may lead to equipment malfunction and malfunction safety risk.In this study

a gasinsulated switchgear(GIS)is established.The evolution characteristics of SF6 leakage and diffusion under various leakage directions

heights and positions of combined electrical equipment.Based on these analyses

effective monitoring and exhaust strategies are proposed.The results indicate that upward leakage of SF6 is sprayed and diffuses to the GIS space along the roof and wall.The downward leakage tends accumulate in the bottom plate and gradually diffuse to both sides.Leakage toward the space on both sides is easy to gather in the local position of the casing and produce the upper and lower shunt. The leakage near the wall is easy to gather high concentration SF6 in the near wall and corner. The diffusion evolution process of leakage SF6 can be characterized by four stages :high-speed ejection

vortex entrainment

inertial diffusion and gravity deposition.The ventilation device should be started activated within 60 s

48 s

15 s and 15 s respectively for upward

left and right sides

downward and near wall leakage scenarios

respectively.Furthermore

recovery or ventilation device should be arranged in the middle of the top/bottom plate of the GIS room

0-6m near the wall on both sides

and at the lower part of the wall on the surrounding side.The research results can provide ideas and practical guidance for optimizing SF6 gas monitoring layout

leakage gas recovery and leakage accident emergency in GIS room.