Research On Rail Potential Monitoring And Limiting Device

Electrified rail transportation, rail is not only the orbit of emus but also an important part of traction reflux system. Because of rail longitudinal resistance and leakage between the rails and the earth, so there is potential different between the rails and the earth, which is rail potential. The rising of track potential abnormally will endanger the safety of passengers, damage the along equipments. However, the operation of track potential limiting device will increase the leakage of stray current. The leakage of stray current makes the underground metal pipeline structure suffered from severe corrosion.In this paper, rail potential is choosed as studying subject, and the distribution of rail potential, monitoring system and limiting device are researched in order to guarantee the safety of passengers, reduce the leakage of stray current and improve the reliability of urban rail transit.First of all, the mathematical models of rail potential of single or more vehicles traveling are established under the unilateral or multilateral supply conditions, the formula of rail potential and stray current are obtained, then through the MATLAB simulation the distribution of rail potential and stray current are obtained.Second, studying of the solutions of rail potential monitoring system. Hardware circuit and software flow diagram of track potential monitor are designed based on TMS320F2812. After studying the CAN bus communication and data transmission through GSM, networking solutions of track potential monitoring system are designed based on GPRS. Describing the composition of track monitoring system, the process of reading voltage data and realized WEB browsing mode are designed.Finally, Research on track potential limiting device. The rail potential limiting device is put forward that just be installed on the platform based on distribution of the rail potential. Combined the movement condition with the working principle of existing track potential limiting device, the defects of track potential limiting device and quadratic optimization the control mode track potential limiting device are analyzed. After optimizing, rail potential limiting device can ensure the personal safety and reduce the leakage of stray current. From the perspective of overall operations of traction power supply system, the importance between rail potential limiting device and other devices and getting setting related with operation are analyzed.