Development Of Online Monitoring Device For Power Distribution System Of EMUs

In recent years,the rapid development of high-speed EMU has not only greatly improved people's travel conditions,but also played a huge role in promoting the economic growth along the route and the optimization and upgrading of related industrial structure.After decades of development,China's high-speed rail train in the technical research and development has achieved the independent design,manufacture,commissioning of the complete chain.At present,with full independent intellectual property rights of the Revival of China's standard train group,in line engineering,column control system,traction power supply and other aspects of the technical level has reached the world's leading level.The power distribution system of the EMU is responsible for supplying power to the on-board AC and DC equipment,and its reliability directly affects the driving safety of the moving group.For example,the power failure of important components such as cooling fans will cause the traction converter of the EMU to overheat to protect the action,which will eventually lead to a serious accident in which the EMU stops.Therefore,the status of the distribution system's various output branch distribution switches,the output current,output power and insulation of three-phase IT systems,need to be monitored in real time.When the branch switch status or branch current and power abnormal,report the early warning information to the EMU,in advance to respond to the security risks of the distribution system.At present,most of the research on the reliability of the power distribution system of the EMU focuses on how to quickly troubleshoot and deal with sudden failures after a failure.In order to ensure the smooth and safe operation of the EMU,it is necessary to carry out planned preventive maintenance for the real-time intelligent online monitoring of the power distribution system of the EMU.To this end,this paper developed a real-time intelligent monitoring of the power distribution system status of the EMU,and timely early warning device.Firstly,the method of fault detection and fault phase determination of the IT system of the EMU is analyzed,and a ground fault detection circuit of THE IT system is proposed.The amplitude of the AC voltage at the detection point in the circuit can reflect whether a ground fault has occurred in the IT system,and its phase can reflect the phase line where the fault occurred.The MATLAB simulation is carried out in view of the determination and phase selection of the ground fault of the it system,and the experimental platform is set up for testing and verification.Secondly,on the basis of the above theoretical analysis,an online monitoring device of the power distribution system of the EMU is developed.The device uses an isolation scheme to monitor the external electrical volume,can monitor the ac incoming line voltage,load voltage,current,power,power factor of the distribution system of the EMU in real time,determine the ground state and ground phase of the AC three-phase 380 V line,and monitor the DC 110 V incoming voltage,load voltage,The current and the status of the AC DC distribution switch,and the above information of the distribution system is reported to the train control system.Finally,the device with the vehicle carried out a real test verification,the verification results show that the proposed method and the developed device to meet the above design requirements.