Research On The Mechanism Of Interaction Of The Explosion-Induced Airflow And The Arc Based On N-S Equations

The trip-out rate of transmission line under traditional lightning protection measures remains high, which is a serious threat to the reliability of the power supply system and people’s production and life. The emergence of a brand-new protection concept -- air-blast arc-quenching gap-- not only makes up for the defects of traditional lightning protection, but also reduces, to a great extent, the incidence of lightning damage to the wiring. The power frequency electric arc produced by lightning strikes triggers the air-blast arc-quenching gap to generate explosive gas flow, which interacts with transient arc at an early stage of development and extinguishes the arc before the action of relay protection. This research creatively takes fluid mechanics into consideration from two angles, the explosion airflow and the arc, and proposes the flow dynamic model based on Euler equation and Navier-Stokes equation as well as the arc dynamic model based on plasma and Maxwell equations, to prove that the air-blast arc-quenching gap for arc truncation is scientific and effective.The parameter calculation method based on CJ theory is proposed to work out the detonation velocity, detonation pressure and wave surface reaction degree in the arcing channel according to the corresponding conditions, from which, the numerical values illustrate that the explosion-induced airflow carries great energy. A large number of HV impulse experiments prove that the air-blast arc-quenching gap can reliably extinguish the arc and has good durability. The variations of the airflow and the arc in the explosion and the coupling process between them were all shot by camera in the experiments we did in Xi’an High Voltage Apparatus Research Institute shot. The duration of the reaction of the air-blast arc-quenching device and the duration of the extinguishing of the arc were also experimented.Simulation analysis of the airflow and the arc by ANSYS AUTODYN displays that a high-speed and energetic airflow produced by the reaction of the device rapidly fills the space and acts on the arc by breaking the dynamic balance of the plasma and thus suppressing the arc in a very short time. By theoretical analysis, parameter calculation, experimental verification and simulation analysis, this paper presents a sound evidence for the scientificity and effectiveness of air-blast arc-quenching gap. It also provides new theoretical basis for research on lightning protection by arc extinction.