The Design Of Visual Grounding Device And Host Computer System For Urban Rail Transit

At present,manual method of hanging and removing earth wire is usually used while at normal maintenance or trouble repair ofpower supply system along urban rail transit among the world.The condition that hanging not following the rules or in fault method and forgetting to remove the earth wire usually occurs for various reasons that operating point of maintenance is widely distributed and the ability of workers can't be guaranteed.And the existing "five-prevention" system can't guarantee the safety of hanging earth wire temporarily,which result in the ignorance of condition of hanging earth wire and the motion can't be put down.According to the problem of disadvantage of manual method of hanging and removing earth and the shortage that it lack of image of the scene of work place,we developed an automatic hanging and removing earth wire system,which combined with the experience of installation,removing,use and management of the existing power earth wire in scientific research institutions at home and abroad and the electric power enterprise.The system contains a visual grounding device and its on-line monitoring system.Grounding switchis used instead of traditional manual method in the grounding device,and two kind of operating method can be selected,local and remote control.Workers can complete the hanging operation with one key,at the same time,the scene of work place can be see through the webcam in Remote dispatching workstation.The presented grounding device in this article is mainly made up of grounding switch and RTU unit.The grounding switch contains operating mechanism,transmission mechanism,action contact and insulated terminal.The hanging and removing operation can be realized by the action of the contact.The RTU units use STM32F107 as the master controller,which is responsible for the state monitoring of all kinds of sensor,temperature and humidity control,and receive or dispatch of data,etc.It realizes the real time monitoring of potential of overhead lines or contact rail.A distributed network is used to control all grounding devices in different areas.The C#language and SQL database is used to code the computer software.In order to ensure the real-time,security,reliability of the system,Modbus protocol is used for data transmission in Communication application layer,and mechanical interlocking device is designed to avoid wrong operation in the process of hanging and removing earth wire.This system has been tested in the laboratory environment,and achieves the expected design goal.Satisfactory results have been achieved.