Research On Grounding Protection Of Single-core Cable For Electrified Railway

Associated with the current rapid development of national economy,the construction of high-speed railway has to enter into a new stage of development,so the grid of high-speed railway construction has become one of the key link,the single core feeder has the characteristics of more adaptable to catenary current is big,so more and more widely used in high speed railway industry,but also need to be in the process of application of the continuous optimization.It also has a great influence on whether the railway power can ensure stable transmission.If the connection of feeder cable is abnormal in the aspect of grounding,the power of traction power supply arm will be lost greatly.Therefore,the grounding mode of cable occupies a very important position in the railway traction power supply system.In this paper,in China and overseas countries,it is concluded that the research on cable laying method is relatively few,especially the research on ground protection mode is far from enough.Therefore,this paper focuses on the research and analysis on this aspect.At first,there is a big difference in the length of feeder cable,and then the design of protective grounding and protective means are improved respectively.Under three different operating conditions(power frequency over-voltage,power frequency steady state,and lightning current impact),theoretical analysis was carried out for different grounding means,and then the feasibility of grounding and protection means was analyzed.Then the simulation model of traction system including feeder cable,traction station and locomotive is used.Based on the analysis of the theory,the author makes a simulation analysis and research on the induced voltage of the protective layer of feeder cable,and then demonstrates the accuracy of its grounding mode.In other words,it is necessary to combine the length of feeder to determine its grounding means.When the length of feeder cable is greater than a certain distance,one end must be directly grounded and the other end shall be grounded(suspended)through the protective protector.When the length of feeder cable is within the range,it can consider introducing the neutral grounding means of cable.When the length of feeder cable exceeds the length,cross grounding or sectionalized protective grounding are adopted.