Research On Key Technology Of UHV Controllable Arrestor

In order to meet the needs of national networking and large-capacity,long-distance transmission,the country is building a UHV transmission grid.However,with the increase of voltage level,the influence of operating overvoltage on the insulation level of power transmission and transformation equipment is also increasing,which becomes the limiting factor of the insulation level of power transmission and transformation equipment,and thus the difficulty in manufacturing transmission and transformation equipment.Including the cost has a huge impact.Domestic and foreign studies have shown that metal oxide surge lighting arresters(mainly zinc oxide surge lighting arresters)can limit the magnitude of the operating overvoltage by absorbing the energy of the overvoltage to some extent.However,in the UHV system,the conventional zinc oxide lighting arrester has shortcomings in economy,pressure limiting effect and operational reliability.In order to overcome these shortcomings,based on the idea of dynamically changing the volt-ampere characteristics of the zinc oxide lighting arrester,some scholars have proposed to utilize The controllable lighting arrester limits the operating overvoltage of the UHV system and conducts some practical explorations.Based on a brief introduction to the development history of lighting arresters and the principle of lightning arresters for overvoltage protection of transmission lines,this paper reviews the technical progress in the research of controllable lighting arresters at home and abroad,focusing on the analysis of the controllable lighting arresters associated with UHV systems.Key technology.Through the research on the prior art scheme of the controllable lighting arrester for UHV system(this article focuses on the research of the controllable switch in the controllable lighting arrester),the problems of the prior art solutions are discovered,including but not limited to the prior art.The effect of the inter-electrode capacitance of the thyristor switch on the voltage distribution of the controllable lighting arrester in the power frequency steady state,the operating shock overvoltage and the lightning impulse overvoltage.And through the simulation software such as saber and matlab,the existing technical solutions are simulated and analyzed,which further proves the problems existing in the prior art solutions.On this basis,the response speed,driving energy source and control complexity of the thyristor switch in the prior art scheme are discussed.According to the existing problems in the technical solutions of the controllable lighting arrester,this paper proposes two new technical solutions to solve the problems in the current technical solutions: one is based on the natural breakdown of the operating overvoltage(thunder overvoltage)The parallel discharge gap,the control of the lighting arrester is realized by the breakdown of the gap,and the technical requirements of the gap are analyzed.Based on the selection of the type of the gap,the advantages and disadvantages of the scheme are analyzed.The other is based on the parallel discharge gap of controlled breakdown under operating overvoltage(lightning overvoltage).Based on the selection of suitable discharge gap,the control problem of the gap is studied and the technical solution is Analysis of advantages and disadvantages.Finally,a new technical solution for the controllable lighting arrester is determined through analysis and comparison.In order to detect the practicability of the controllable gap in the new technical scheme of the controllable lighting arrester,the working characteristics of the key components of the controllable gap in the new scheme are verified by the combination of simulation and experiment,which indirectly verifies the feasibility of the new scheme.