New Protection Scheme In All Parallel At Traction System

Traction network is an important part of the railway power supply system.Its large scale and direct exposure to the natural environment is extremely vulnerable to wind and rain thunderbird beasts and various failures.In the existing traction network protection scheme,any failure of the traction network may cause the entire power supply arm to trip and expand the scope of the accident.Therefore,it is particularly important to discover,isolate and eliminate faults in the traction network in a timely and accurate manner,and to ensure the continuous and stable power supply of the traction network.At the same time,it is of great theoretical and practical value to further optimize the traction network relay protection scheme,minimize the scope of power loss,and improve the reliability and flexibility of traction network power supply.The brief summary about the already existing program of AT power supply protecting system is described in this paper.By analyzing the characteristics of voltage and current under lots of traction network faults,on the basis of the segments of traction network power supply program,with current differential protection,the program of the AT power supply system-used distributed current differential protection system is established.It uses low voltage short-circuit failure criterion as its characteristics and uses optical current differential protection.Program achieves the protection of each line in each individual AT segment,narrows down power failure range and the reliability of power supply are improved.A distributed AT traction network observing and controlling model has been built to simulate short circuit of traction network by using MATLAB/Simulink simulation software,and the data of T-R,F-R,T-F faults is analyzed.The simulation verifies that the current differential protection program is selective.This paper discusses the data acquisition and transmission,fault record and data processing in the current differential protection system,which is of great significance to the whole protection system components.