Protection Scheme Of Longitudinal Segemented All Pararrel At Power Supply

As china’s economic and social continuous development, the advantages of high speed railway cut a striking figure at the construction and development of railway in china. About high speed railway, the power supply mode, external power supply voltage rating, wiring form of traction transformer, traction substation main wiring scheme, AT (auto transformer) post main wiring scheme and so on have been extensive researched and development. At present, the all parallel AT power supply mode is widely adopted in high speed railway put into operation in china, the biggest drawback of this power supply mode is that when the traction network fault, the circuit breakers of up and down feeders at the outlet of traction substation will be all unified tripping, and then splitting the all parallel system, at last the circuit breakers which are located in traction substation, AT post and section post will be reclosed one by one for troubleshooting. In this case, when a permanent fault occurs at the traction network, the whole fault power supply arm will be power outage, expanding the scope of power outages, affecting the normal operation of the railway.Longitudinal Segmented All Parallel AT post main wiring scheme is improved on the basis of All Parallel AT post main wiring scheme, correspondingly, the Longitudinal Segmented All Parallel AT traction power supply system can be well overcome the shortcoming that when a fault occurs the range of power outage is large in traditional all parallel AT traction power supply system. With the changes in the structure, the protection configuration scheme of traditional All parallel AT traction power supply system is no longer applicable, the protection configuration scheme must be redesigned by combining the structural characteristics of the Longitudinal Segmented All Parallel AT traction power supply system.Firstly, the structure and characteristics of Longitudinal Segmented All Parallel AT traction power supply system are introduced in this paper, focusing on the.composition and operation mode of Longitudinal Segmented All Parallel AT post main wiring scheme. Secondly, the simulation model of Longitudinal Segmented All Parallel AT traction power supply system is established by using MATLAB/Simulink software, the short circuit impedance characteristics respectively at the position of sub-station, AT post and section post are obtained by simulation when common short-circuit faults occur in traction network.Finally, according to the above theory and simulation analysis, combined with the structure and fault characteristics of Longitudinal Segmented All Parallel AT traction power supply system, a set of protection scheme of traction network and transformer is proposed, and the setting principle is given, the relationship between actions and time limit of breakers in traction network is analyzed when common short-circuit faults occur in traction network.