Contrastive Study On The Implementation Scheme And Technical Parameters Of Lightning Conductor Of High Speed Railway

With the continuous development of Chinese high-speed railway,mileage of high-speed railway in our country has been ranked first in the world.The climate,topography,and geological of electrified railway are different.The catenary is easily struck by lightning.Lightning fault has become an important factor which endangers the safe operation of high-speed railway in our country.Therefore,it is necessary to study lightning protection of high-speed railway.In this paper,the erection scheme,grounding mode and height of lightning conductor are studied.The research in this paper has an important reference for the design and construction of lightning protection of high speed railway in the future.This paper introduces two kinds of lightning conductor erection scheme including setting up lightning conductor and raising protection wire in AT power supply mode.ATP-EMTP is used to establish the simulation model of contact network.At the same time,lightning protection performance of two different kind schemes is evaluated based on electrical geometry model(EGM).The results show that back-flashover lightning protection level of elevating protection wire increases about 20%.The back-flashover lightning protection level of setting up lightning conductor increases about 40%.It has little effect on shielding-failure protection level.Further analysis shows that two lightning protection schemes can improve the shunt coefficient and coupling coefficient.At the same time,lightning trip-out rate is studied in this paper.The lightning trip-out rate of raising protection wire decrease about 64.9%and setting up lightning conductor decrease about 70.4%.The back striking trip-out rate also increase after the modification of contact network.And the back striking trip-out rate increases with the increase of grounding resistance.At the same time,this paper analyses the design method for height of lightning conductor.The selection principle of ball radius in both single and double track under the condition of high speed railway is also studied.This paper has established the advantages of rolling ball method in design of the height of lightning conductor.At the same time,with the increase of the height of lightning conductor,the shielding failure trip-out rate gradually reduced and trip-out rate of back striking increased gradually.The total trip-out rate decreases gradually and then increases slowly.Through further analysis,the ball radius can be selected in accordance with the third ball radius in the areas with no severe thunderstorm activity.And in the areas with severe thunder activity,the ball radius can be selected according to the second radius.Finally,this paper also analyzes lightning protection performance of two different grounding schemes including interval earth reconstruction mode and partial insulation transformation method.The results show that the lightning withstand level improves better after the transformation.The lightning withstand level without transformation is almost not affected when the interval earth reconstruction mode is adopted.The lightning trip rate is also improved when the transformation distance is less than 200m.The trip-out rate do not change much when the transformation distance is more than 200m.The interval earth reconstruction mode although partially improve the lightning withstand level of pillar,this mode can reduce overall lightning trip-out rate.And it can effectively reduce the investment cost of project.We can choose the reconstruction distance according to the situation.