Study of Time-Frequency Characteristics of Contact Force Signal and Parameter Sensitivity of Catenary of High-Speed Railway

With the increasing train speed, catenary fluctuation and pantograph vibration are intensified, the pantograph–catenary contact force (PCCF) at the dropper point increases, and the current collection quality of pantograph–catenary contact deteriorates. This study performs the location analysis of the PCCF characteristics based on the simulation method to reduce the PCCF value at the dropper point. First, the key wavelength component and the corresponding amplitude component (ac) of the PCCF at the dropper point were located using the time-frequency representation, which is the continuous wavelet transform (CWT). It was found that the PCCF signal at each dropper point considered the dropper spacing wavelength (DW) and span wavelength (SW) as the time-frequency characteristics (TFC) components; however, its contribution to the current collection quality for each dropper point was different. Second, the ac change rule of the DW and SW was analyzed by changing the tension and linear density of the catenary. Third, the sensitivity analysis method was used to quantitatively analyze the relationship between the catenary design parameters and the ac of the PCCF at the dropper point. Moreover, the quantitative analysis of PCCF was conducted based on the positioning analysis. It is concluded that the influence of catenary tension and linear density of messenger wire on the key ac is significant. Finally, the catenary structure was optimized via the parameter sensitivity coefficient when the train was running at 450 km/h speed. The results show that the current collecting quality of pantograph–catenary is improved effectively.