Fault Location Technology Of Co-phase Power Supply System Based On Multi Terminal Electrical Quantity

The Co-phase power supply technology can effectively improve the power quality of China’s electrified railway and cancel the neutral sections at the outlet of substation and section post.AT power supply mode is widely used in heavy haul and high-speed railways because of the advantages of low voltage loss and long power supply distance,the Co-phase power supply system with AT power supply mode can further improve the power supply capacity.The traction network is in direct contact with the natural environment and in mechanical contact with the pantograph for a long time for sliding power supply,which is prone to various short-circuit faults.There are many operation modes in Co-phase power supply system,including single power supply and bilateral power supply.Its topology is diverse and the power flow distribution is complex,the existing traction network fault location method is only suitable for a single fault scenario,which is difficult to carry out unified fault location.Therefore,for the Co-phase power supply system with AT power supply mode,it is of great significance to study a unified fault location scheme suitable for different operation modes to improve the reliability of Co-phase traction power supply system.Firstly,based on the generalized symmetrical component method,the four-phase composite sequence network model of traction network with different operation modes of Co-phase power supply system is established.Combined with the critical conditions of different short-circuit fault types,the short-circuit impedance characteristics of AT traction network under bilateral power supply and single power supply are analyzed,which provides a theoretical basis for fault location of traction network.Secondly,based on the 1-sequence network model,a unified fault location algorithm suitable for different operation modes based on multi terminal electrical quantities is proposed.The influence of rail impedance on unit sequence impedance of traction network is eliminated by asymmetric coordinate transformation of traction network voltage and current.Considering the asymmetry of conductor parameters of traction network,a fault location correction method is further proposed to improve the location accuracy.Finally,based on MATLAB / Simulink software platform,the AT traction network simulation model of Co-phase power supply system is built,the short-circuit fault simulation of traction network is carried out under various fault scenarios,and the results of the proposed method are compared with those of traditional methods.The short-circuit simulation test of traction network is carried out on the experimental platform of Co-phase power supply system,which is mutually verified with the simulation results,which proves the effectiveness and accuracy of the proposed method in this paper.