Application Of New Multi-Chamber Surge Arrester In Lightning Protection For 10kV Overhead Power Distribution Lines In Xiamen

In the distribution system of electric power grid,overhead distribution lines are characterized by large quantity,long lines and a wide range and have occupied the largest part in electrical,wiring.To thoroughly analyze different fault types of overhead lines in distribution network,overvoltage wiring acts as the major reason,of which lightning-stroke overvoltage is the greatest incentive.It will exert larger influence in the area of frequent lightning or more flat open areas.The power sector has been devoted to developing effective methods to reduce lightning-stroke disasters suffered by overhead distribution lines,controlling lightning fault rate of overhead distribution lines in a minimal scope,and further enhance power supply quality under a higher reliability of current power distribution.Currently at home and broad,the method applied in lightning protection of overhead distribution lines is to adopt the idea of four defensive lines including"preventing lightning,no flashover in lightning,no trip in flashover,and no power cut in trip".There are two types of ideas in lightning protection:"blocking type" and"scattering type".The blocking-type lightning breakage protection method is to reduce lightning flashover probability of overhead insulated lines,or prevent arcing in power-flow current after lightning flashover and protect insulated lines form lightning-stroke breakage.Its lightning-proof effects are related to various uncontrollable factors such as soil resistivity and ground-grid resistance,insulation strength,lightning types(shielding failure,back flashover)and lightning current amplitude and steepness,height of tower,which is not only expensive but also may lead to unfavorable lightning-proof effects.The scattering-type lightning breakage protection method is to scatter power-flow current arcing after flashover of overhead insulated lines caused by lightning and lead to specific parts of gold fitting for burning and prevent insulated lines from breakage after the lightning.Without affecting national economy and industrial production,we should reduce the harm caused by lightning strike within the controllable range of power sector as far as possible and ensure safe operation of the power system.In terms of the above ideas,this paper has firstly investigated and analyzed lightning protection measures adopted at home and abroad,and compared advantages and disadvantages of several lightning-proof measures;then conducted analysis and calculation of impacts of direct and induced lightning strokes on overhead lines of the distribution network and lightning breakage mechanism,found out main reasons for lightning-stroke breakage in Xiamen and problems existing in lightning protection of power network there,and proposed lightning-proof methods applicable to lines in special mountainous areas in Xiamen.According to the research results and on-site practices,a new multi-chamber surge arrester measure is selected' and taken,this lightning-proof product has adopted a simple quenched arcing technique.Through case analysis of engineering application and comparison of data before and after its application,it has achieved good effects,which can effectively guide operation of design work lightning-proof design in overhead lines of the distribution network in Xiamen.Meanwhile,the paper has lastly raised some limitations existing in the current product and pointed out an improving direction for further research.