While the process of urban transportation electrification is advancing rapidly, the corresponding increase in energy consumption and negative effects are also increasing rapidly. The rapid growth of energy consumption in urban rail transit has brought a burden to the sustainable development of urban rail transit. In 2018, Beijing, Shanghai, and Guangzhou subway loads accounted for 1.5%-2.5% of the city's total load, becoming the largest single load of the urban power grid [1]. Under the "dual carbon" policy, the replacement of the urban rail system with the ATO driving mode, photovoltaic + subway and other methods have achieved good carbon reduction and energy saving effects. The demand-side response of the urban rail system can reduce the cost of traction energy consumption while ensuring passenger satisfaction [2], and further explore the potential of urban rail system for carbon reduction and energy saving.
During the operation of the train, various frictions will occur between the train and the outside world, which will consume the energy of the train traction. During the operation of the train, many factors are considered, such as the friction between the train and the track, the air resistance of the train, the change of the potential energy of the train, and the position speed limit during the operation of the train. During the same journey, trains using different driving strategies usually produce different energy and time consumption.
The running process of a single train between two platforms is shown in Figure 1.
Figure 1. The running process of a single train
Question 1
assumes that a train runs on a horizontal track from platform A to platform B with a distance of 5144.7m, the upper limit of the running speed is 100km/h, the mass of the train is 176.3t, and the train rotates The rotational quality factor of the component inertia is p = 1.08, the maximum traction force of the train motor is 310KN, and the maximum braking force of the mechanical brake component is 760KN. The resistance experienced by the train satisfies the Davis resistance equation f = 2.0895 + 0.0098v + 0.006v2, the speed unit in this formula is m/s, and the resistance unit is KN.
How do you write a program using modeling methods to obtain the speed-distance curve, traction braking force-distance curve, time-distance curve and energy consumption-distance curve of the train running process? How long does the program take to run? Need to get the train to arrive at platform B in the shortest time, and increase the shortest running time by 10s, 20s,
50s, 150s, 300s arrive at platform B, a total of six sets of curves.
In the actual situation of train operation, there are more factors to be considered and the model is more complex. The speed limit of different road sections during the train journey is different, and there are also different slope conditions during the journey, and the dynamic characteristics of the motor are more complicated. In addition, the energy storage device has an important application in the field of train energy saving
. , a certain percentage of energy will be stored in the energy storage device for subsequent use. As shown in Figure 2.
Figure 2. Operational journey in complex road conditions
Two appendices are provided for this question. Road condition data from XEQ station to SMKXY station and train-related parameter data including motor traction/braking dynamic characteristics. The introduction is as follows:
Attachment 1: Road condition data from XEQ station to SMKXY station (xls format), which includes
slope change information and speed limit change information on the way from XEQ station to SMKXY station. See Annex 1.xls for details. Table 1. Traffic data format from XEQ station to SMKXY station
| Distance(m) | Gradient(‰) | Station Name | speed (km/h) |
| 0 | 0.0617284 | Xierqi | 100 |
Appendix 2: Appendix 2 introduces the dynamic characteristics and parameters of the motor and gives the static motor traction rate and braking regeneration rate. See Annex II.docx for details.
Question 2
considers the road condition information in Annexes 1 and 2 and the complex dynamic process of the motor. If the planned running time of the train is T, please design an optimization scheme to obtain a feasible speed trajectory, so that the energy consumption during the running process can be reduced (the lower the better). Referring to question 1, obtain a total of six sets of curves for the train to arrive at platform B in the shortest time, and add 10s, 20s, 50s, 150s, and 300s to the shortest running time to arrive at platform B.
Various emergencies may occur during the operation of the train, which may cause the train to arrive at the platform in advance or arrive at the platform delayed. The speed trajectory of the train needs to change according to the new arrival time.
Question 3.
The train starts from the starting point and arrives at the end point after 320s. When the train reaches the 2000m position, it needs to be delayed by 60s to reach the end point due to sudden accidents ahead. Please design an optimization scheme that can quickly (the sooner the better) obtain the adjusted optimal speed trajectory while maintaining the energy-saving operation of the train. Make the speed-distance curve, traction braking force-distance curve, time-distance curve and energy consumption-distance curve of the train running process
。
references:
[1] Hu Haitao, et al. "Transportation Energy Internet Architecture and Key Technologies." Proceedings of the Chinese Society for Electrical Engineering 38.01 (2018): 12-24+339. doi :10.13334/j.0258-8013.pcsee.171969.
[2] Yang, Hongming, et al. "Coordinated demand response of rail transit loa d and energy storage system considering driving comfort." CSEE Journal of Powe r and Energy Systems 6.4 (2020) : 749-759.
appendix:
Attachment 1: Traffic data from XEQ station to SMKXY station
Appendix 2: Motor traction/braking dynamic characteristic parameter data