Study On Safety Design Of SF₆ Gas Insulation Substation(GIS) Chambers

GIS internal fault arcs cause shell in molten state or burn out. Arc energy will make temperature and pressure of the SF6 gas increase, causing shell plastic deformation even explosions. In order to prevent the accident occurred frequently, the safety design of the gas chambers becomes more and more important, which has a direct relationship with the pressure and temperature distribution of the chambers causing by the fault arcs. Therefore the pressure and temperature distribution in SF6 GIS become the focus of the research. The main factors effect the pressure and temperature of the chambers can be summarized as:air pressure, arc current, L/D, chamber volume, arc position. This paper according to the different factors and use the CFD software FLUENT established different simplified models. Summarize different factors on the pressure and temperature fields of the gas chambers. It provildes data for the safety desgin of SF6 GIS chambers in the engineering field. The main work and conclusions are as follows:1) This paper makes models of the SF6 GIS chambers, the numerical simulation assumptions:Considering the effects of Lorentz force and getting the induction intensity B by Biot theory. The potential equation solves by using UDS. The source of the energy equation and the momentum equations, radiation treatment and the set of the physical properties use the method of programming UDF. It is the secondary development of FLUENT. This paper Uses k-εturbulence model, and sum the viscosity coefficient of laminar and turbulent.2) Summarized the five factors:air pressure, arc current, L/D, chamber volume, arc position effect the distribution of the pressure and temperature of the chambers. It gets the equation of the air pressure and the maximum pressure of the shell, the equation of the arc current and the maximum pressure of the shell, equation of L/D and the maximum pressure of the shell. This provides the data for the safety design of SF6 GIS.3) The highest pressure position is related to the arc position, and is not related to the other four factors. The high pressure position of the shell is at the corresponding arc center. The dangerous positions of the shell follow the change of the arc position.4) Through comprehensive analysis of air pressure, arc curent, L/D,volume, to decide install the bursting disc whether or not.