Research On Shock Response Charactiristics Of High-speed Railway Integrated Grounding System

Lightning stroke faults have a serious effect on railway safe operation in our country. When the lighting strokes the high-speed railways, lightning current flows in the integrated grounding system and disperse in the soil, the potential of connecting ground wire and rail will be increased, the communication, signal equipment which is connecting with the connecting ground wire along the railway will be broken, and the train operation accidents, casualties will be happened if seriously. Shock response characteristics of high-speed railway integrated grounding system must be studied for reducing the damage of lightning failures.Connecting ground wire is the main part of high-speed railway integrated grounding system in our country. The structures grounding device of bridge, tunnel and catenary post foundation used as the grounding electrode. The other grounding devices of the equipment along the railway will be connected with the connecting ground wire. So, the integrated grounding system is very complexity and long. And it is far from the grounding system in power system.The model of integrated grounding systems in subgrade, bridge and tunnel have been established in CDEGS. Shock response characteristics of high-speed railway integrated grounding system have got by a large number of simulating calculation. At first, the industrial frequency grounding resistance and impulse grounding resistance of subgrade integrated grounding system have been calculated. The impulse grounding resistance of subgrade integrated grounding system is bigger than its industrial frequency grounding resistance, and the value of the industrial frequency grounding resistance increases and impulse grounding increases proportionally with the earth resistivity. The flow paths of the lightning current in the subgrade integrated grounding system have been analyzed when the point of strike is different. Then, the grounding performances of connecting ground wire and catenary post foundation have been studied. The connecting ground wire grounding performance is better than the catenary post foundation’s, and eighty percent lightning current disperse in the soil in two hundred and fifty meters apart from the point of strike have been found. And then, the influence factors of shock response of subgrade integrated grounding system have been analyzed. The earth resistivity, the point of strike and the amplitude of lightning current have a seriously influence on the shock response potential amplitude and safety distance of connecting ground wire and rail. The radius of connecting ground wire almost has no effect on shock response. At last, the shock response characteristics of bridge and tunnel integrated grounding system. The shock response potential amplitude and safety distance of connecting ground wire and rail in the bridge is bigger than the subgrade’s. The shock response potential amplitude of connecting ground wire and rail in the tunnel integrated grounding system is oscillation, and the safety distance cannot be calculated. The result in this paper can serve as a reference for the design and construction of the railway integrated grounding system.