Study On Fault Analysis And Protection Of Metro Low Voltage Distribution System

Metro low voltage distribution system for railway signal system,communication system,electric power monitoring system,fire automatic alarm system,fire protection system,environmental monitoring system,integrated monitoring system,vending ticket system,and other professional equipment and the station station hall station lighting and equipment room lighting supplied with power,is to protect the traffic equipment function in normal and safety critical systems.Low voltage distribution system is the key equipment to ensure the normal power supply of the user equipment.It plays an important role in the safe,stable and efficient power supply.Compared to the Tianjin Metro Line 1 low voltage distribution system is only self cast function,Tianjin Metro Line 2,3 line of low-voltage power distribution system in addition to self cast function has increased the self complex function.When the power supply system of the abnormal situation,since the switching function in the low voltage distribution equipment fast recovery of station important load power supply,when the power supply system to restore normal,re enable low-voltage power distribution equipment automatically resume normal operation mode.the closed loop fault is when the two incoming lines are in the closing state,busbar switch automatic closing,form closed loop caused under impact load equipment,wavelet and a wide range of elevator arrest,communication interrupt signal,station lighting flash off,belonging to the significant security risks,with Metro Industry enhancements to the safety requirements,the ring fault analysis and control of more and more attention to.The subway industry did not fundamentally solve fault rings,only in after the failure of the passive disposal through analysis study of ring fault reasons,according to the design specification and operational requirements to determine the effective ring governance solutions and verification methods,from fundamentally avoid the fault ring,to ensure the reliability of power supply of low voltage power distribution system.Therefore,it has important practical significance and application value to carry out the research of fault analysis and protection of subway low voltage distribution system.