Study on the Diffusion Law of Pyrolytic Characteristic Gases in the Outer Sheath of High-Voltage Cables Based on Computational Fluid Simulation

Early warning of fires in high voltage cables can be realized by detecting pyrolysis characteristic gases in the outer sheath of high voltage cables. In order to effectively detect the characteristic gases with low concentration and uneven distribution, their distribution characteristics should be studied. With pyrolysis gases CO and H2 as characteristic gases, the simulation study of pyrolysis characteristic gas diffusion and distribution law of PE outer sheath of high-voltage cables in cable tunnels was carried out based on Computational Fluid Dynamics (CFD). The results show that the diffusion characteristics of the characteristic gases are mainly determined by the diffusion coefficients and temperature difference under the closed and unventilated conditions, and the characteristic gases are mainly distributed symmetrically in the axial direction at the fault point, and The diffusion rate of H2 in a closed environment is greater than that of CO. which provide theoretical references for the sensor arrangement strategy of early warning of high-voltage cable fires.