| The urban rail AC power supply system has a special structure that uses cables as the traction return component,which makes the system have the characteristics of large power supply capacity,long distance,stable power supply,etc.At the same time,the system adopts the AC power supply system supplemented by the in-phase power supply technology,making it free of impurities The advantages of stray current,continuous power supply,and regenerative energy can be directly used to eliminate the equal distribution of electricity.Compared with the existing urban rail DC traction power supply system,it can save complicated stray current management schemes and reduce the number of traction stations,bringing certain economic and environmental Therefore,the urban rail AC power supply technology is a good choice for urban rail transit.Firstly,the structural characteristics of the urban rail AC power supply system are introduced.On the basis of reasonable equivalence,the system’s centralized parameter equivalence model is constructed.Based on the system circuit topology characteristics,the system traction network current distribution formula,traction network equivalent impedance formula,Formula for voltage drop of traction network during single-line and multi-line operation.Then,build a Simulink simulation model to verify the correctness of the theoretical derivation formula.Finally,taking the voltage loss of the traction network as the limiting condition,the calculation process for determining the furthest power supply distance of the single arm of the system is given.Through an example analysis,it is found that the furthest power supply distance of the single arm can reach more than 41 km,When the main substation is in the middle position,the power supply distance can reach more than82 km,which is far better than the existing subway DC power supply scheme.Secondly,according to the structural characteristics of the urban rail AC power supply system,the system chain network model with 0.5km as the division unit was established through the multi-conductor transmission line theory,the calculation principle and process of the locomotive constant power flow algorithm were introduced,and the Simulink simulation model was established,Simulation verifies the accuracy of the system power flow algorithm.Then,the urban rail line 2 of a city was transformed to use the urban rail AC power supply technology,and a constant power flow algorithm for the locomotive was compiled to analyze the power flow of the line.The distribution law and limit value verify the electrical feasibility of using the urban rail AC power supply technology on the line,and finally explore the distribution rule of the rail potential,verifying that the existing railroad rail potential control measures can effectively control the system rail potential.Finally,based on the establishment of the distributed chain network model of the urban rail AC power supply system and the locomotive constant power flow algorithm,the rules of parallel resonance and series resonance of the system are explored.Firstly,the equivalence model of combined harmonics of locomotive-traction network was established.The principle of modal analysis method for parallel resonance of the system was introduced.The number of locomotives,locomotive position,locomotive power,power supply arm length and traction cables were replaced with bare wires.The parallel resonance law of the system under multiple operating conditions.Secondly,it introduces the principle of branch circuit analysis to analyze the series resonance of the contact network of the system.The law of network series resonance.This study is of great significance to the progress of urban rail AC power supply technology engineering. |
PDF Full Text Request