Results in Engineering (Jun 2024)
Mechanism of rail potential imbalance in long tunnel based on GA and analysis of improvement and optimization measures
Abstract
As the quick advancement of urban rail transit, the power supply safety is gradually receiving attention. In the direct-current traction power supply system, the abnormal increase in rail potential is very significant, seriously affecting the regular working of the system. Therefore, to address the above issues, the mechanism of abnormal increase in rail potential is explored, and genetic algorithms are applied to optimize the power distribution of the system. The simulation results show that when the starting threshold is 1600 V, the highest value of the rail potential is only about 40 V, which is reduced by about 70 V compared to the other thresholds of 1800 V. When two trains are running in the system, as the travel time of Train 2 increases, the cross-zone transmission current gradually increases to around 1100 A. And the rail potential first decreases and then increases to over 90 V. It can be seen that the power distribution situation has a significant impact on the rail potential. After genetic algorithm optimization, the peak potential of the rail is only 66.2 V, with a decrease of 40.3%. The regenerative braking power allocated by the upstream regenerative braking train Cs1 to the accelerating train Cs2 decreases to 2703.5 kW, with a decrease of 35.6%. In addition, the regenerative braking power allocated by the Cx 1 regenerative train to the accelerated train Cx 2 is 2738.7 kW, which is at least 35.6% lower than before optimization. The above results indicate that the power distribution situation has a significant impact on the abnormal increase of rail potential. And optimizing the power distribution situation through genetic algorithm can effectively avoid the abnormal increase of rail potential.
