Study On The System Of Hanging And Removing Earthing Wire Visually And Automatically On Metro Contact Line

When maintaining the metro contact line, earthing wire is needed to be hanged on both ends of the working area after the contact line is powered off, and be removed when the operation is completed and the contact line is powered on. One end of the hanged earthing wire is connected to the contact line, and the other end is connected to the rail. The electric potential of the contact line is equal to the rail after earthing wire is hanged, thus, safety of operators and equipment is ensured. The traditional way of manual hanging and removing earthing wire has problems that the operation steps is complicated, a lot of manpower and material resources is needed, and it takes much time and is unsafe, and so on. Wrong operation of hanging and removing earthing wire and other accidents is often occurred. In order to solve the problems existing in the process of traditional manual operation, a system of hanging and removing earthing wire visually and automatically on metro contact line is proposed combining with the existing research and practice experience at home and abroad.Firstly, the overall design of the system is given. The system is composed of a visual grounding device, a visual monitoring host and a monitoring station in information management center. With each part working together, remote visual automatic operation of hanging and removing earthing wire can be realized.Secondly, software and hardware of each layer of the system are designed in detail. With Siemens S7-1200 PLC being as controller, the visual grounding device communicate with devices using the standard Modbus TCP protocol. IP camera is installed inside the grounding device to monitor the grounding switch and upload video frame to the monitoring system. The visual monitoring host uses Siemens S7-1200 PLC as the main controller. Through the address mapping between PLC of monitoring host and grounding device, monitoring of all the grounding devices in current station can be realized. The visual monitoring software of monitoring host is written by C# with functions such as control of grounding switch, status monitoring, access of IP camera, and history storage and query.Again, automatic monitoring of the grounding switch is realized from two aspects of motion detection and image recognition. With the motion detection of the grounding switch, the video can be recorded automatically when the grounding switch begins to move, and alarm and prompt can be generated when error action is occurred. With the image recognition of grounding switch, the on/off state can be recognized automatically. Manual operation is further reduced with the automatic monitoring of the grounding switch, also valuable time for the maintenance of the contact line is saved.Finally, the main modules of the system are tested. According to the system design, the prototype of the visual grounding device is developed. The simulated visual grounding monitoring system is built and functions of the system are tested.