Research On Fouling Characteristics Of Roof Insulators On Hainan Roundabout Line

The good insulation performance of the roof insulator is related to the reliability of the operation of the Electric Multiple Units(EMUs),and the complex and changeable landforms and natural environment faced during the operation of the EMUs will reduce the insulation performance of the roof insulator,thus affecting the normal operation of the train.Operational experience shows that the insulation accident probability of insulator on Hainan roundabout line is higher than that in other areas.For example,during the operation of Hainan CRHAF-A EMUs,local arcs are often generated on the roof insulators.Since pollution is an important factor leading to the reduction of insulation performance,this paper takes the roof insulators of EMUs as the research object,and uses natural fouling test and numerical simulation analysis to study its fouling characteristics and influencing factors,and the structure of roof insulator has been optimized.First of all,in this paper,the insulation performance test of the roof insulators of the EMUs under field operating conditions is carried out,and its natural fouling characteristics and the main factors affecting the insulation performance are analyzed from five aspects:spatial distribution,content distribution,unevenness,NSDD/ESDD,and composition.It is found that there is a streak-shaped pollution distribution in the local arc high-incidence area,and the pollution level can reach severe and above.Secondly,the deposition and slip criteria of salt spray droplets are deduced,the fouling model of salt spray droplets on the surface of roof insulator is constructed,and the effects of different wind speeds,structures and parameters of salt spray droplets on the fouling characteristics of roof insulator are proved,thus further revealing the formation law of natural fouling characteristics.Finally,the influence of streak-shaped pollution on the electrical performance of insulator is analyzed,and it is found that streak-shaped pollution is an important factor that causes local arcs in roof insulator.Based on the turbulent agglomeration theory,the formation mechanism of streak-shaped pollution is analyzed,and an optimized streamlined shed structure is proposed,which effectively suppresses the formation of streak-shaped pollution and reduces the pollution area by 82%.