As an important part of electrified railways, the pantograph and catenary system (referred to as pantograph system) provides strong traction power for the stable operation of electric locomotives through sliding contact. The complex multi-field coupling effect will affect the current acceptance quality and friction and wear performance of pantograph, and it is of great significance to carry out the research on the multi-physics coupling effect of pantograph contact in electrified railway pantograph, which is of great significance to reduce the operation and maintenance cost of pantograph and improve the service life of pantograph slide plate and catenary wire.
In the actual operation of pantograph mesh, the intervention of electrical factors will make the friction interface exhibit a series of unique tribological phenomena, which makes the behavior of the current-carrying friction pair more complicated. This complexity is not only manifested in the damage form and damage mechanism of the slide plate and the contact wire, but also in the requirement that it have good contact conductivity and friction and wear characteristics at the same time. Therefore, in the study of the electrical effect of the contact surface of the pantograph-mesh system, scholars at home and abroad have analyzed the change law of its characteristics through experiments or the establishment of corresponding models, and have achieved some valuable results.
With the increase of train running speed, the pantograph network offline occurs frequently, which will produce arc discharge, and the arc discharge will send out strong electromagnetic interference to the surrounding environment, and the high-frequency electromagnetic radiation generated by the pantograph arc will affect the surrounding communication equipment. Therefore, the electromagnetic interference generated by the electrified railway pantograph system has also been the focus of attention.
Based on the mechanism analysis and a large number of field test results, three typical types of electromagnetic radiation noise in pantograph-mesh systems are proposed. In view of the electromagnetic radiation interference phenomenon generated by offline arcing, the time and frequency characteristics of the disturbance are studied, and the empirical distribution of the time-domain parameters of the radiated electromagnetic noise of the pantograph network is obtained, and the results show that the radiated noise of the pantograph network arc has a wide frequency band, which has a certain impact on the normal operation of the train communication system.
Considering the influence of electromagnetic interference in the working environment of the pantograph, a pantograph robust control strategy based on state estimation is proposed, and the effectiveness and robustness of the controller under different working conditions are verified in the nonlinear pantograph-catenary model. The proposed state estimation method can accurately obtain the pantograph state, and the controller can effectively reduce the fluctuation of contact force and improve the current receiving quality of the pantograph system under the condition of pantograph parameter perturbation.
The electromagnetic interference phenomenon of pantograph network is complex and has many influencing factors, and the factors affecting electromagnetic noise include working condition parameters such as contact current, contact pressure and running speed, and it is of great significance to obtain the relationship between pantograph arc electromagnetic noise and operating parameters, which is of great significance to suppress the interference of electromagnetic noise.
Some literature uses the self-developed pantograph-net arc electromagnetic noise experimental system to analyze the frequency domain characteristics of the pantograph-net contact current in the offline state, and uses the total harmonic distortion rate of the contact current to characterize the conductive electromagnetic noise characteristics of the pantograph-net offline, and establishes a mathematical model of the total harmonic distortion rate of the contact current, which can be used to further study the conductive electromagnetic noise characteristics of the pantograph-net sliding electrical contact.
However, some literature has experimentally measured the time-domain characteristics of electromagnetic radiation noise generated by a single arc under different distances and currents, and found that the time-domain waveform of electromagnetic noise is symmetrical and convergent. On this basis, a large number of single-arc discharge experimental waveforms are used to establish a mathematical model of the time-domain waveform of electromagnetic radiation noise, which can improve the time-domain waveform of the electromagnetic compatibility network and shorten the electromagnetic compatibility test time. The distribution characteristics and influencing factors of electromagnetic noise in pantograph-mesh arc have been studied by changing the contact pressure, contact current and sliding velocity, and the relationship between electromagnetic noise and experimental parameters has been analyzed, which provides a theoretical basis for further research on the suppression method of pantograph-net arc electromagnetic noise.
In recent years, combined with the methods of experimental research and analysis, scholars have analyzed the electromagnetic noise characteristics of pantograph arc radiation in the time domain and frequency domain by detecting the electromagnetic radiation signal near the pantograph, and the frequency distribution of arc radiation obtained is of great significance for suppressing the electromagnetic interference of pantograph arc.
However, due to the particularity of pantograph-net arc, there are still many problems to be studied to understand the influence mechanism of pantograph-net offline arc electromagnetic interference, and the research on high-frequency electromagnetic interference generated by pantograph-net arc is still not deep enough, especially there is no applicable arc model for high-frequency electromagnetic radiation generated by arc. In the later research, attention should be paid to the research on high-frequency electromagnetic radiation to reveal the influence mechanism of pantograph arc electromagnetic interference in the high-frequency region.
The results of this work were published in the 10th issue of Transactions of China Electrotechnical Society in 2023, *titled "Research Progress on the Electromagnetic Thermal Coupling Effect of Pantograph-Net Sliding Electrical Contact". This project is supported by the National Natural Science Funding Project of China.