Railway cable on-line monitoring and fault positioning device and system

The utility model provides a railway cable on-line monitoring and fault positioning device and system, comprising a data acquisition module which is connected to a CPU central processing unit through a high-speed A/D data conversion module and a programmable module; and the voltage waveform data acquisition unit is used for acquiring voltage traveling wave data of a two-loop power distribution substation or a box transformer substation outgoing cable. Through on-line monitoring of the cable grounding ring current, monitoring of a railway cable operation health state can be realized, and a larger grounding short circuit accident and a cable combustion accident caused by gradual damage of cable insulation can be effectively avoided. And meanwhile, the cable fault positioning function can realize accurate positioning of fault points in real time after cable grounding and short circuit faults occur, so that manpower, material resources and financial resources for searching the fault points are greatly reduced and