Study On Shielding Effectiveness Of Carriage For High-Speed Electric Multiple Units

In recent years, due to the development of railway transportation with heavy loads and at high speed, requirements for tractive power become higher. It follows directly that more high-power traction apparatuses which spread widely are used. It leads to the deterioration of electromagnetic environment in carriage. Meanwhile, more and more attentions should be paid to protect the microelectronic devices located in carriage, which is used for communication or controlling from electromagnetic interference. Otherwise, the improperly operating of these devices caused by electromagnetic interference would become the most serious problem which threatens the safety of railway transportation.Previously, improving the external immunity of on-board sensitive equipment to electromagnetic interference and restraining the electromagnetic emission of high-power traction apparatuses are the major parts of improving countermeasure for electromagnetic environment inside the carriage. Those two solutions are based on "Sensitive Equipment" and "Disturbance Source". In this dissertation, research was done to block the "Transmission Path" of electromagnetic disturbance. The electromagnetic environment of carriage is considered as a whole. Analysis of shielding effectiveness in carriage was performed to search for potential impact factors to electromagnetic shielding, with purpose of increasing the shielding effectiveness of electric multiple units (EMUs) and making the electromagnetic environment ameliorate. In this dissertation, mechanism of electromagnetic shielding was analyzed first. Then EMC tests of electromagnetic environment in EMUs and in equipment trunk under the carriage were done. Data of distribution of electromagnetic field and low frequency magnetic field were collected so as to find the main souse of electromagnetic disturbance of carriage. Furthermore, a model of EMUs was set to simulate the field distribution inside the carriage under different frequency range with a kind of software, which is widely used as simulation software and has excellent application in simulating problem of electric large size. The shielding effectiveness of 8 different points in 24 models with difference in shape of windows, size of windows and number of windows were intercompared and analyzed to find out what is the key factor to influence shielding effectiveness. The conformity of experimentation and simulation had been verified the rationality of the simulation model. Results of the experimentation compared with the simulation exhibited the urgency and importance of improving electromagnetic environment in EMUs. In the last part of this paper, some advises was given for the purpose of improving electromagnetic environment.