The Study On Electric Field Simulation For Arc-quenching Chamber Of AC Filter Circuit Breaker

With the lift of voltage level and the continuous improvement of system capacity,the power system puts forward higher requirements on the insulating property of high voltage switch electrical equipment.In recent years,the Alternating Current Filter(ACF)breaker of the convertor station has occurred a number of accidents.Based on operating characteristics of ACF breaker and comprehensive analysis of those accidents,it can be inferred initially that the main reason for the accident is several disadvantages in internal insulation design of the breaker,or field distortion caused by metal foreign matters included in arc quenching chamber,which led to arcing chamber burst.Since this kind of accident in HVDC systems occurred in a row,and so far there is no systematic accident analysis and technical solutions,which has seriously endangered the normal operation of power grids.Hence,in this paper,aiming at ACF circuit breakers,the theoretical analysis and simulation study of internal insulation property are carried out.Then the theoretical support for the technical requirements,anti-accident measures and related standards of filter switching breakers is provided.Firstly,the numerical analysis methods applied to the simulation of engineering electromagnetic field are introduced.For the electric field simulation of power frequency ACF circuit breaker arcing chamber belongs to the category of electrostatic field,the basic principle of electrostatic field is expounded.Secondly,based on SolidWorks,a 1: 1 three-dimensional simulation model of arcing chambers in the four manufacturers is established.ANSYS finite element software is adopted to calculating the maximum electric field strength of the four manufacturers circuit breaker parts within 5 ~ 10 ms after the breaking current,and which is compared and analyzed in the following.The influence of arc time and breaking speed on the maximum field strength is studied.Afterwards,based on the analysis of the forming reason and main components of the metal particles in the arc extinguishing chamber,three kinds of metal particles model,positive tetrahedron,positive hexahedron and sphere,are established respectively,and the effects of whose size,position and radius of curvature on the distortion electric field are studied.Moreover,based on the arc time and breaking speed of circuit breaker,the maximum field strength of the arc chamber is optimized further.This paper could offer help to find the cause of the accident,and it may have an important application value in the power grid,and expected to prevent similar accidents happened in the operation of the DC system.