Lightning Protection Mechanism And Experimental Research Of 110kV Multi-chamber Arrester

This paper proposes a new kind of 110kV multi-chamber arrester for lightning protection of 110kV transmission line.It allows arc channel to be established in multi-chamber structure after lightning flashover.AC arc extinguishes at current zero within half of a power frequency cycle,thus avoiding the occurrence of lightning trip-out.This kind of lightning arrester is simple in structure and cheap in cost.Meanwhile,it faces some troubles in the application and dissemination process,for instance,the lack of relevant mechanism research,the arc extinguishing ability to be verified and the range of application to be researched,and so on.This paper firstly proposes the lightning protection mechanism,combining the characteristic of AC arc with the structural features of multi-chamber structure,and researching the free-of-reignition condition of power arc in a chamber through test.When arc channel established after lightning flashover,due to the arc burning,high pressure gas is generated in the chamber with one side opening.It removes the arc outside of the chamber,then accelerates the deionization of the arc.A large power arc is divided into a large amount of short arc in multi-chamber structure,therefore,the dielectric recovery strength is raised due to the superposition of cathode voltage drop of short arc.Test results show that the arc in chamber with 8mm in sphere diameters and 1mm in gap,will not reignite after current zero under the action of 300V power frequency voltage.Then,according to the requirement of system voltage,make the number of chambers more enough through calculating,thus ensuring the maximum voltage distributed on a single chamber not more than 300V under the action of power frequency voltage,which can ensure the arc extinguish reliably.Based on the lightning protection mechanism of multi-chamber arrester,this paper proposes the parameter design requirements of 110kV multi-chamber arrester,and then ascertain the structure of chamber,blowing arc channel and multi-chamber structure.In order to raise the the withstand voltage and discharge stability of 110kV multi-chamber arrester,propose the structural design of multi-chamber structure and one large discharge gap in series.According to the requirement of are extinguish ability and lightning protection,ascertain the essential parameter of 110kV multi-chamber arrester with 490 in chambers number and 0.52m in length of large discharge gap,through power frequency follow current test and lightning impulse test.Finally,according to the requirement of standards,evaluate the electrical performance of 110kV multi-chamber arrester in rain and pollution.The test results show that the flashover voltage of the arrester is 190kV in rain and 110kV in heavy pollution,both of whiich are lager than the maximum of power overvoltage.Therefor,it can be applied to heavily polluted areas.110 kV multi-chamber arrester proposed in this paper satisfies the requirements of lightning protection and reliable operation of 110 kV transmission line.The research prospect of the arrester with simple structure and no need for maintenance is preferable.