Research On Fire Detection In High Voltage Switchgear Based On Fluorescent Fiber Optic

High voltage switchgear plays a vital role in ensuring the safe and reliable operation of power systems.Operating in a closed environment for an extended period,the switchgear is susceptible to insulation deterioration or mechanical damage,which can lead to breakdowns,fires,and substantial economic losses.However,fluorescent fiber,which uses light as a sensing information carrier,offers several advantages,including resistance to electromagnetic interference,high insulation strength,corrosion resistance,and high sensitivity,making it well-suited for fire detection in switchgear.So this paper proposes a set of bases high voltage switchgear fire detection system based on fluorescent optical fiber can realize the early detection of fire.First of all,this paper investigated and counted many cases of high voltage switchgear fire,and analyzed the fire characteristics and causes of each accident.The main causes of high voltage switchgear fire were summarized into three categories:cable insulation fault,phase-to-phase insulation fault and contact overheating.Then,the most common cable insulation fault is selected as the research object,and the simulation model of fire evolution of high voltage switchgear fault is established by using FDS simulation software,and the disaster value caused by cable insulation fault of switchgear is simulated.Finally,based on the simulation results,the mechanism of cable fire and its temporal and spatial evolution are analyzed.Secondly,this paper builds a fire detection test platform,which mainly includes optical sensor,optical transmission module,photoelectric conversion device,power module and electrical signal acquisition device.The effects of color,incident Angle,distance and length of fluorescent fiber on the performance of fluorescent fiber were studied experimentally and theoretically.According to the experimental results,the optimal arrangement scheme of fluorescent fiber was determined.The blue or white fluorescent fiber with a central wavelength of 440nm was selected as the fire detection sensor.In order to ensure its transmission efficiency,the length of the fluorescent fiber was selected as 2m and placed 20cm away from the flame.Finally,this paper chooses KYN61-40.5 high voltage switchgear,which is the most common in actual field application,as the research object,and selects three typical defects of single-phase grounding,phase-to-phase insulation and contact overheating for fire fault simulation.Considering that the absorption spectrum of fluorescent fiber is ultraviolet band,a layer of chemical substance is coated on the surface of the cable skin based on the principle of flame color reaction,so that the emitted spectrum can be detected by fluorescent fiber.The experiment shows that when the fire starts,the original signal will change obviously,and the fire signal can be detected successfully,which verifies the feasibility of the system.In this paper,a fire detection system of high voltage switchgear based on fluorescent optical fiber is built,which provides strong support for high voltage switchgear fire detection.