Study On The Corona And The Optimization Of Insulator On The Wire

There are metal or non-metal particles in the surrounding environment.They will change the distribution of the electric field around transmission line,and the distribution of the electric field directly determines whether the coronawould take place and the severity of the corona around the line. In recent years,the air pollution made line environment have some change. How the shape andsize of metallic and nonmetallic particles affect the corona loss on the line is abasic problem of power system. It impacts the security and the economicoperation of the power system.Insulators are basic components of the powersystem. Its shape not only affects the electric field distribution inside or aroundthe insulator, but also affects the lightning trip out rate. This paper studies thesetwo problems, the main research contents are as follows:1Study on the effects of corona of metal particles on the transmission bythe method of corona area.This paper used calculation software Ansoft to establish the physicalmodel of transmission line, arranged metal particles of different shapes on thesurface of the line, and calculated the electric field distribution in each case. Inaccordance with the electric field strength in the air30kV/cm as the standard,draw the region that would produce corona, defined it as the corona area. Thearea’s size could reflect the influence on the corona loss. The study found:when there were metal particles adhered on the line,the maximum electric fieldintensity round the line would become large significantly;comparing the givenshape particles,this study found that cubic particles had a greatest influence onthe corona loss; if there were hemispherical metal particles of different radiiadhered on the line,there would be a certain radius of particles of the metaldome,which could cause a maximum corona loss.2Study on the corona loss of non metal particles on the transmission line. Studying on the corona loss of non metal particles on the transmission lineby the method of corona area,this paper found:when non metal particlesadhered on the surface of transmission line, the electric field intensity increasesequally, the non metallic particles of small radius (0.5mm~1.5mm) adhered tothe wire still could cause corona, but the corona area disappeared with theincrease of the radius,.3The comparison of corona loss between non metal particles and metalparticles on the transmission lineComparing of the corona loss between metal and non metal particlesadhered on the transmission line surface,the article found:when the metalparticles adhere on the transmission line surface the electric field strengthbecame larger, and it made a larger corona loss, in other word, it have greaterinfluence on the transmission line.4Study on the influence factors of electric field distribution of theinsulatorTaking10kV binding porcelain insulator as an example, this paper studiedsome typical factors that effect the distribution of electric field intensity,like thelength of the insulator, insulator sheds’ number and shape, the shape of theinner electrode.Draws the following conclusions: the insulator sheds had a verysmall influence on the maximum electric field intensity of insulator,but it couldeffect the degree of uniformity of electric field of the insulator,the smallernumber of the rib of the insulator,the more uniform the electric field intensitythe insulator would have; the length of the insulator effected the insulator’smaximum electric field intensity, the longer the insulator was,the smallermaximum electric field intensity the insulator would have;the inner electrode’sradius of insulator had a very small impact on the maximum electric fieldintensity of insulator, however, the rod diameter of the inner electrode ofinsulator was bigger, the maximum electric field intensity on the surface of theinsulator became larger.5Influence of insulator shape on the lightning trip out rate According to the calculation results, the article found: the longer theinsulator was,the smaller the maximum electric field strength it wouldhave,also the average electric field intensity was smaller, then the lightning tripout rate became smaller;the number and length of the rib of the insulatoreffected the uniformity of the electric field near the insulator, the more rib theinsulator had and the longer the rib was, the electric field around the insulatorwould more nonuniform, then the average electric field intensity was larger,this made the lightning trip out rate became higher. On the premise of enoughclimbing distance and economy,the designer could increase the insulator’slength and reducing the number of umbrella rib on the same time.This wasbeneficial to the insulator’shape optimization.