The Design Of Stray Current Monitoring Device And Host Computer System In Metro

At present, the rail transit system of metro adopts DC electric traction. The current required by the vehicles flows out from the traction substation, and then pass through the OCS (Overhead Contact System) and the running rails. At last, the traction current will return to the traction substation. A proportion of the traction current will leak to earth, such leakage current is called stray current.The stray current will affect the rail transit system itself and buried metal structure by causing corrosion,and influence the transit system lifetime and safety.lt is highly neccessery realize effective monitoring of stray current.This paper in depth analysis the monitoring principle of stray current,and provides an on-line monitoring system of stray current in metro. From the aspect of system control and data processing of on-line monitoring system, designs a stray current monitoring device and an host computer system. Take C8051F020 for the control of the core, designs and implements in the subway stray current monitoring system for the monitoring device module. The module describes the overall design of the monitoring device, hardware circuit design and software design.In the hardware circuit design has taken into account EMC protection. Gives the running results of the monitoring device. Host computer system software is designed with Visual Basic and SQL Sever, provides functions of monitor system control, monitor information inquiry, monitor information store, monitor data illustrate, error alarm, etc. Discusses the designing scheme, process a running interface.Transition resistance and longitudinal resistance measurement is a stray current monitoring difficult. This in-depth analysis of the transition resistance and longitudinal resistance of the algorithm on-line measurement principle. Using Newton's iteration method in matlab programming for algorithm simulation. Combination of simulation results, the actual parameters and algorithms efficient solutions of the scope of the discussion, summarized proposed algorithm in practical application conditions. Finally, achieves the calculation on the monitoring device which based on C8051F020.