Semi-active Dampers for Multiple Pantograph Operation

Multiple pantograph operation is an unfavourable condition for current collection, since the trailing pantograph is subjected to high vibrations and elevated contact force variations, due to the perturbation induced on the overhead line by the leading pantograph. In a previous work it was shown that a diversification of preloads of front and rear pantographs, achievable using pressure regulation systems driven by electronic units, can have beneficial effects on current collection quality of the trailing pantograph. This paper investigates the concepts of differentiating the leading and trailing pantograph damping, and of varying the pantograph damping as a function of speed. A plan of numerical simulations is first performed considering a number of permutations of leading and trailing pantograph damping values, obtaining a map of optimal damping values for different train speeds. The numerical model of an electro-hydraulic damper, able to adapt its damping parameter is then proposed and integrated in the PCaDA model for the simulation of the dynamic interaction between pantograph and catenary. The numerical results corroborate the idea that the regulation of damping values as a function of train speed and orientation would allow improving the system performances and extending the operating speeds.