Study on Lightning-Induced Plasma Extinguishing in 10 kV Distribution Network Lines Based on Electronegative Gas Trifluoroiodomethane

Plasma arcs generated by lightning strikes are prone to tripping distribution lines, especially 10 kV lines. To reduce the lightning-induced tripping rate of 10 kV distribution lines and ensure the safe operation of power systems, this paper proposes a same-level double-fracture lightning protection device containing the electronegative gas trifluoroiodomethane (CF₃I). A mathematical model of the gas arc-extinguishing process is established based on magnetohydrodynamics. Meanwhile, the mechanism of CF₃I in the arc-extinguishing process is analyzed according to its physical and chemical properties, and the arc-extinguishing process is simulated using COMSOL Multiphysics 6.0. The results show that (1) the arc-extinguishing effect is optimal when the horizontal distance of the compression pipeline of the device is 9 mm; (2) under the action of power frequency currents with different initial phases of π/2 and 0, the arc-extinguishing device can extinguish the arc within 800 <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mrow><mi mathvariant="sans-serif">μ</mi><mi mathvariant="normal">s</mi></mrow></mrow></semantics></math></inline-formula> without re-ignition; and (3) in the arc-extinguishing process involving CF₃I, the arc can be extinguished within 710 <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mrow><mi mathvariant="sans-serif">μ</mi><mi mathvariant="normal">s</mi></mrow></mrow></semantics></math></inline-formula>, which is 11.2% quicker than that without CF₃I. Meanwhile, CF₃I can effectively reduce the arc temperature at the initial stage of arc extinguishing, avoiding damage caused by excessive internal compression of the device.