Study On The Mechanism And Arc State Of Gas Blowing And Extinguishing Arc

One of the major mine hazards in power systems is the incalculable annual cost of lightning protection worldwide.After the transmission and distribution network is struck by lightning,the lightning current waveform will propagate along the transmission wire.When the lightning pulse is transferred to the pole tower side,because the tower will be grounded by the grounding resistance,there will be a large potential difference on both sides of the insulator connecting the tower and the conductor.When the potential difference is greater than the breakdown discharge voltage of the insulator,the insulator will flashover along the surface to form an impact arc.After that,the continuous flow of the working frequency on the wire will provide a stable heat source to the arc channel,which will make the arc develop to the new energy balance state,resulting in the steady burning of the arc.The continuous arc will form a huge power frequency short circuit current to the power system,which will eventually lead to lightning tripping accident.The gas-blown arc-extinguishing device is a new type of arc-extinguishing lightning-proof gap which has attracted much attention in recent years.Itis an external-energy arc-extinguishing device.Its design principle: when the electrode gap of the arc-extinguishing device induces the insulator flashover,the extreme speed triggers the arc-extinguishing unit,the explosion produces high-speed airflow,and the strong current is coupled with the arc of the flashover channel,thus diluting and dissipating the arc energy and finally cutting off the arc to avoid causing the system short-circuit fault.According to the above idea,this thesis carries on the related simulation and the experiment research to the gas blow-out arc lightning protection gap mechanism,the arc development,the coupling process,the content key points include:(1)This paper analyzes the development of 110 k V insulator bypass impact arc and power frequency arc based on MHD magnetic fluid mathematical model,The power of convection heat dissipation,radiation heat dissipation and conduction heat dissipation play an important role in arc energy balance.(2)Air-arc coupling process for arc and arc extinguishing process of insulator by-pass flashover in power transmission line is simulated based on Comsol Multiphysics multi-physical coupling simulation platform.the change law of the whole arc development process is observed directly through images,data tables and figures,and the weak links in the arc development process are found,which not only deepens the understanding of the arc itself and the coupling effect of high-speed airflow and arc,but also provides a theoretical reference for thedevelopment and improvement of arc extinguishing engineering technology.(3)Test the response time of gas-pill and arc-extinguishing process of the gap of the arc-extinguishing device,collect the voltage or current signal in the arc-extinguishing circuit,combined with the image analysis of the high-speed camera,it is concluded that the device can react quickly after receiving the pulse signal to extinguish the arc successfully.In general,theoretical analysis,simulation analysis and experimental analysis are carried out on the process of gas-producing and blowing-out arc mechanism of arc or gap device.