Research And Test Analysis Of High Speed Railway Traction Network Segmented Measurement And Control System

Traction power supply system is the only power source of high speed railway electric multiple unit(EMU).As the weakest link of traction power supply system,improving the reliability of traction network is the most effective way to improve the reliability of traction power supply system and to guarantee the safe and stable operation of high speed railway.The existing traction network protection scheme takes the whole feeding section as the protection unit.Unfortunately,any fault of traction network will cause the whole feeding section power supply interruption,widening the range of power failure and affecting the normal traffic organization.Meanwhile,accurate traction network fault location technology can save the time for fault repair,so that the problem of traction network fault location has been the focus of research.Thus,it's significant to study a more effective traction network protection and a more accurate fault location scheme.Firstly,based on the analysis of the existing high speed railway traction network protection scheme,combined with measurement and control system for traction network,according to the features of faulted electrical quantities,the reduced voltage starting criterion and current differential protection criterion are applied for traction network protection in AT(auto transformer)power supply mode,and protection scheme based on two terminal electrical quantities of traction network is established,taking the AT segment as the protection unit.Theoretical analysis and simulation results indicate that the proposed protection scheme can effectively reduce the range of power failure and has higher selectivity.Secondly,with the generalized method of symmetrical components,the sequence network model of traction network is established and the characteristics of short circuit impedance are analyzed.Furthermore,the impedance characteristic curves of AT traction network are presented.And then,the fault location method of high speed railway traction network using two-terminal electrical quantities is proposed in this paper,and the process of fault location is illustrated.Simulation results indicate that the method proposed is efficient and has higher accuracy,which provides a new way for the fault location of the existing high speed railway traction network.Finally,combined with the Da(Tong)Xi(An)passenger dedicated line,the engineering application of traction network protection and fault location scheme based on two terminal electrical quantities are also studied in this paper.Through the implementation of traction network short circuit test of different fault types in different locations,the reliability of the proposed traction network protection scheme is verified,and the validity of the fault location scheme is also proved by the analysis of the fault record data,which providing an important reference for its subsequent engineering applications.