Study On Key Technologies Of Mountain Rail Traction Power Supply System

China is rich in mountain resources,but due to the terrain and environmental protection requirements,the development of mountain rail transit lags behind seriously.Taking Sichuan Province as an example,the mountainous areas of Western and southern Sichuan have short railway mileage and low road network density,which are difficult to meet the travel needs of local residents,and the inconvenient transportation seriously restricts the economic development of mountainous areas.In recent years,Sichuan Province has planned and constructed 23 mountain rail lines with a total mileage of 2520 km.Under this background,it is of urgent practical significance to study and plan the technical scheme of traction power supply system suitable for mountain rail transit.Firstly,after comparing the characteristics of the existing traction power supply systems,the technical scheme of traction power supply system for mountain rail transit is given,and expounds the composition of traction substation and cable traction network under the twolevel voltage power supply structure.By comparing the characteristics of different types of catenary,combined with the characteristics of mountain rail transit,this paper analyzes the advantages of using contact belt and electric plow compared with traditional catenary.Under the background of reducing axle load of mountain train,the voltage level of contact belt is demonstrated from the perspective of insulation distance and adaptability of on-board converter,and the feasibility of selecting 3kV voltage level is analyzed.Finally,analyzing the capacitance effect of cable traction network and the necessity of compensating cable reactive power,and proposing the method of compensating cable reactive power by using co-phase power supply device in traction substation.In view of the different electrical characteristics between this power supply scheme and the traditional traction power supply scheme,studying the power supply characteristics of cable traction network,and the equivalent model of this system and the loop current distribution law are given.Then,the calculation formula of voltage loss of contact belt is deduced.Combined with the variation law of contact belt voltage and locomotive traction power under 3KV voltage level,the maximum power supply distance of adjacent traction substation is calculated.Finally,analyzing the capacitance effect of cable traction network and the necessity of compensating cable reactive power,and the method of compensating cable reactive power by using in-phase power supply device in traction substation is proposed.Studying the calculation method of reactive power compensation capacity for cable traction network,and the reactive power collaborative compensation control method of multiple traction stations based on central controller is proposed,the distribution formula of reactive power compensation capacity of each traction station is given.Then,based on the principle of negative sequence compensation of co-phase power supply system,a cooperative compensation strategy combining cable reactive power compensation and load negative sequence compensation is proposed.Finally,designing the traction power supply system scheme of a mountain rail line,and the system simulation model is built.Analyzing the electrical characteristics of the cable traction network under this power supply scheme,and the coordinated compensation control strategy of the traction station is simulated.The compensation effect is satisfactory,which verifies the feasibility of this power supply scheme and compensation method.