A Fault Recording & Positioning Device For Metro Traction Network Based On IEC61850

The construction of subway has become one of the effective measures to alleviate the surface traffic in large and medium-sized cities,and it is also an important manifestation of the comprehensive strength of each big city.Subway vehicles are provided with electric energy by DC traction power supply system,but the latter is prone to line failure,which directly affects the safety of subway operation.Under the influence of such factors as short running interval,high traffic density and variable vehicle running pattern,the existing feeder protection device frequently misoperates,which brings great unsafe factors to the subway operation.In addition,the fault point is in the tunnel after the fault occurs,so it is difficult to judge the fault point location.Therefore,it is necessary to introduce IEC61850 communication protocol,propose high order statistics algorithm and impedance based subway traction network fault location algorithm,to carry on the device design and simulation analysis,improve traction network fault recording method and propose a new feeder fault location protection method,which has very important practical significance for subway operation and maintenance.This thesis first describes the composition and operation characteristics of the subway traction power supply system,and analyzes the main protection configuration of feeder protection in detail.This thesis points out the problems existing in the protection of the feeders of the existing DC traction network,distinguishes the normal traction load current from the short-circuit fault current,and analyzes the mechanism of the short-circuit current and special load current(oscillating current)in the traction network.Secondly,aiming at the problem that DDL protection cannot distinguish the oscillating current from the fault current and the problem that the distance protection of subway traction network is not accurate,the feeder current high-order statistic algorithm and the fault location algorithm of subway traction network based on impedance characteristics are proposed.In order to improve the network protection,IEC61850 series communication standard is introduced to complete the communication model of subway traction network.The rationality and feasibility of the scheme are verified by the modeling and simulation of OPNET software.Finally,on the basis of previous theoretical research,the hardware design of the device is carried out by USB-4711 A data acquisition card and embedded system,the software design of the device is carried out by Lab VIEW software,and the real-time simulation platform of RT-plus is used to verify the feasibility of the device by simulating various short-circuit points of different distances.A large number of experimental results show that the designed device can effectively avoid the influence of two types of oscillating currents and the range of ranging error is less than 20 m,which verifies its reliability.