Method for improving subway train bow net abrasion in winter

Abstract

The invention belongs to the technical field of subway trains, and discloses a method for improving subway train bow net abrasion in winter. Setting an environment humidity target humidity value; setting metro train humidity measurement sensor measuring points; controlling the spraying humidification module; and controlling the environment humidity. The lower limit of the target humidity value of the environment humidity is set as 55% RH; the humidity value transmitted to the master console by the wireless transmitting module is compared with a target value, and when the current humidity is lower than the target humidity value of the environment humidity, a signal for controlling to start the spraying and humidifying module is transmitted and is transmitted to the wireless receiving module by the wireless transmitting module to control to start the spray head device; and when the current humidity is equal to or greater than the target humidity value of the environment humidity, the master console sends a signal for closing the spray humidification module, and the local control box closes the spray head device. According to the invention, the problem of abnormal abrasion of the pantograph catenary caused by humidity reduction in winter during metro operation is solved, and great economic value and social value are achieved.

Description

Technical Field

[0001] This invention relates to the field of subway train technology, and in particular to a method for improving pantograph-catenary wear in subway trains during winter. Background Technology

[0002] More than 50 cities in China have opened subway lines. The pantograph-catenary system, as a key current-collecting component of electric locomotives, plays a crucial role; its stability and current-collecting quality directly affect the safety and reliability of the train. As an open friction system, the current-collecting and frictional characteristics between the pantograph's carbon sliding plate and the contact wire are strongly affected by the external environment, and complex operating environments will affect the service performance of the pantograph-catenary system. Due to the space constraints of subway tunnels, rigid contact wires are mostly used, resulting in poor pantograph-catenary interaction and making them prone to abnormal wear. In recent years, abnormal wear of the pantograph-catenary system has occurred frequently in subways across the country, especially in winter, causing significant economic losses and safety hazards. The study "Wang Yuting. Experimental and Simulation Research on Thermoelectric Characteristics of Pantograph-Catenary Friction Pair under Rain Conditions [D]. Liaoning; Liaoning University of Engineering and Technology, 2018" shows that large changes in temperature and humidity have a significant impact on pantograph-catenary contact. In recent years, there have been many studies on the influence of environmental humidity on current-carrying wear. "Sun Yixiang. The Influence of Humidity on the Wear of Pure Copper Current-Carrying Devices [D]; Henan University of Science and Technology, 2017" points out that humidity affects the contact state through adsorption and chemical reactions, thereby affecting the tribological properties and wear mechanism of the friction pair. "Wang Meng. Research on the Friction and Wear Behavior of a Pantograph Slider under Humid Conditions [D]. Liaoning; Liaoning University of Engineering and Technology, 2018" indicates that the influence of humidity on the friction and wear behavior of the pantograph slider follows a U-shaped pattern, meaning there exists an optimal environmental humidity. “SHANGGUAN B, ZHANG YZ, XING JD, et al. Study of the Friction and Wear of Electrified Copper against Copper Alloy under Dry or Moist Conditions [J]. Tribology Transactions, 2010, 53(6): 927-32.” and “Sun Yixiang, Yue Yang, Song Chenfei, et al. Effect of relative humidity on current-carrying wear of copper materials [J]. Journal of Henan University of Science and Technology (Natural Science Edition), 2018, 39(1): 1-4+117.” indicate that spraying can effectively reduce the wear rate of copper alloys, and that Joule heating and arc heating during electric contact can effectively reduce wear by vaporizing water. “Li Hanxin, Ji Dehui, Shen Mingxue, et al. Effect of ambient humidity on current-carrying tribological behavior of carbon / copper sliding contact pair [J]. Journal of Tribology, 2022, 42(04):709-718.” indicate that there is an optimal humidity around 55% RH that minimizes the wear of the pantograph-catenary system. The above research is limited to the laboratory bench test stage and cannot be used to improve the humidity environment of the pantograph-catenary contact area during subway operation.

[0003] Currently, there are no effective measures to improve the humidity of the subway tunnel environment, let alone methods and devices to improve the humidity of the pantograph-catenary contact area in real time during subway operation. Summary of the Invention

[0004] In view of the shortcomings of existing technologies, this invention proposes a method for improving pantograph-catenary wear in subway trains during winter.

[0005] The technical solution of the present invention is as follows: A method for improving pantograph-catenary wear in subway trains during winter, comprising the following steps:

[0006] S1. Set the target humidity value for the ambient humidity;

[0007] S2. Set up the humidity measurement sensor measurement points on the subway train;

[0008] S3. Control the spray humidification module;

[0009] S4. Control the ambient humidity;

[0010] The humidity value transmitted to the central control unit by the wireless transmission module is compared with the target value. When the current humidity is lower than the target humidity value, a signal is sent to control the opening of the spray humidification module. The signal is then sent from the wireless transmission module to the wireless receiving module to control the opening of the nozzle device. When the current humidity is equal to or greater than the target humidity value, the central control unit sends a signal to close the spray humidification module, and the local control box closes the nozzle device.

[0011] The target humidity level is set to a lower limit of 55%RH.

[0012] Inside the subway train tunnel, a humidity sensor is selected as the measurement point for tunnel humidity. The humidity sensor is installed on both sides of the tunnel wall. The humidity sensor detects the humidity in the tunnel in real time and transmits the data to the central control console via a wireless transmission module. The humidity sensor is then compared with the target humidity to control the spray humidification module.

[0013] The spray humidification module is located in the tunnel and controls the humidity.

[0014] The spray humidification module is a tunnel foam-water spray combined system. The nozzles are installed on the tunnel sidewalls, and the spray humidification modules are placed at an average interval of 400m to 500m.

[0015] Each of the spray humidification modules is equipped with 5 nozzles, which are oriented diagonally upwards, with a nozzle spacing of 5m and an installation height of 12.75m.

[0016] Step S4 specifically involves comparing the data detected by the subway train humidity measurement sensor with the target humidity value of the environment. When the humidity is lower than the target humidity value, the device activation information is sent to the wireless receiving module, and the local control box activates the nozzle. When the data detected by the subway train humidity measurement sensor is higher than the target humidity value, the local control box controls the nozzle to shut down.

[0017] The beneficial effects of this invention are: real-time humidity values ​​inside the tunnel are obtained by setting up a humidity measurement sensor for subway trains inside the tunnel, and a spray device is installed on the side wall of the tunnel.

[0018] Based on the optimal humidity value for pantograph-catenary friction performance and the difference between the actual humidity value and the target value in the tunnel, the spray device is controlled to be turned on or off, thereby improving the humidity in the pantograph-catenary contact area of ​​the tunnel.

[0019] Due to reduced humidity in winter, abnormal wear of the pantograph and catenary becomes extremely severe. The normal wear rate of the carbon sliding plate on the pantograph head is 0.5 mm / 10,000 km, but during abnormal winter wear, the wear rate can reach 40 mm / 10,000 km, reducing the replacement cycle of the carbon sliding plate from one year to one week. Since each carbon sliding plate costs around 7,000 yuan, this results in significant losses. This invention solves the problem of abnormal pantograph and catenary wear during subway operation caused by reduced humidity in winter, and has significant economic and social value. Attached Figure Description

[0020] Figure 1 The coefficient of friction under different relative humidities;

[0021] Figure 2 The cumulative arc energy and average contact resistance under different relative humidity conditions;

[0022] Figure 3 A schematic diagram illustrating the mechanism of current-carrying friction and wear in response to changes in ambient humidity;

[0023] Figure 4 Layout diagram of humidity measurement sensors on a subway train;

[0024] Figure 5 Schematic diagram of the layout of the spray humidification module;

[0025] Figure 6 This is a flowchart for tunnel humidity control. Detailed Implementation

[0026] This invention addresses the significant impact of environmental humidity on pantograph-catenary wear. Taking optimal air humidity as the starting point, it improves the pantograph-catenary wear by installing a spraying device in the catenary area of ​​the subway tunnel and controlling the humidity of the pantograph-catenary contact area during train operation through spraying. This results in a method and apparatus for improving the tribological performance of the subway pantograph-catenary contact.

[0027] The technical problem to be solved by the present invention is to provide a method for improving the contact tribological properties of the pantograph-catenary system in subways to address abnormal wear caused by reduced humidity in winter.

[0028] The present invention relates to a method for improving pantograph-catenary wear in subway trains during winter, comprising the following steps:

[0029] S1. Set the target humidity value for the ambient humidity;

[0030] Based on the positive correlation between humidity and cumulative arc discharge energy and average contact resistance, and the relationship between adhesive wear and humidity, such as Figure 1 and Figure 2 As shown, the average friction coefficient decreases monotonically with increasing humidity under no-current conditions. However, under current-carrying conditions, the friction coefficient remains relatively high at 10% RH, while there is no significant change in the average friction coefficient after the humidity increases to 35% RH. This is because increased relative humidity increases the amount of water vapor in the air, and some of this water vapor is adsorbed and accumulates on the material surface, forming an adsorbed water film in the contact area, which provides a certain degree of lubrication. Furthermore, the cumulative arc discharge energy and average contact resistance are positively correlated with relative humidity, indicating that the cumulative arc energy increases significantly in low relative humidity environments. Therefore, the decrease in ambient humidity in winter is detrimental to the pantograph-catenary friction performance.

[0031] Meanwhile, changes in humidity affect the mechanism of pantograph-catenary friction and wear, such as... Figure 3 As shown. In low humidity (10% RH) environments, there is very little water vapor, and a large number of fine copper particles and wear debris adhere to the wear surface. The main wear mechanisms are adhesive wear and abrasive wear. In medium humidity environments (35%-55% RH), water vapor increases, and an incomplete adsorbed water film gradually forms in the contact area. The water film acts as a lubricating film, reducing adhesive wear and abrasive wear. At the same time, an electrochemical oxidation reaction is induced under the action of electric current. Water molecules are ionized into hydroxide ions and oxygen ions, causing oxidation of the material surface. At this time, the wear mechanism is a combination of slight adhesive wear, abrasive wear, and oxidative wear. In high humidity environments (80% RH), the water vapor continues to increase, further improving the integrity of the water film. The electrochemical oxidation reaction intensifies, and the ribbon-like film formed by copper oxide tends to be complete. At this time, the main wear mechanism is oxidative wear, accompanied by adhesive wear.

[0032] Therefore, taking into account the influence of ambient temperature, the lower limit of the target ambient humidity value is set at 55%RH.

[0033] S2. Set up the humidity measurement sensor measurement points on the subway train;

[0034] Inside the subway train tunnel, the installation locations of the subway train humidity measurement sensors were selected as the tunnel humidity measurement points. The subway train humidity measurement sensors were installed on both sides of the tunnel walls, such as... Figure 4 As shown, the humidity inside the tunnel is detected in real time by a humidity measurement sensor on the subway train, and transmitted to the central control console via a wireless transmission module. The humidity is then compared with the target humidity to control the spray humidification module.

[0035] S3. Control the spray humidification module;

[0036] A spray system was installed in the tunnel to control humidity. A dedicated tunnel foam-water spray system was selected, with nozzles installed on the tunnel sidewalls at an average spacing of 400m to 500m. Five nozzles were installed, facing upwards at an angle, with a spacing of 5m between nozzles, and an installation height of 12.75m. (Details are as follows...) Figure 5 As shown.

[0037] The system compares the humidity data detected by the subway train's humidity sensor with the target humidity value. When the humidity level falls below the target value, it sends a notification to activate the device. Figure 4 The wireless receiving module in the system controls the opening of the nozzles via the local control box. Similarly, when the detected humidity value is higher than the target value, the local control box controls the nozzles to close.

[0038] S4. Control the ambient humidity;

[0039] The humidity value transmitted to the central control panel via the wireless transmission module is compared with the target humidity value. When the current humidity is lower than the target humidity value, a signal is sent to control the activation of the spray device. This signal is transmitted wirelessly to... Figure 4 The wireless receiver module controls the opening of the spray nozzles. When the current humidity is equal to or greater than the target value, the central control panel sends a signal to shut down the spray system, which is then activated by the local control box.

Claims

1. A method for improving pantograph-catenary wear in subway trains during winter, characterized in that, The steps include the following: S1. Set the target humidity value for the ambient humidity; S2. Set up the humidity measurement sensor measurement points on the subway train; S3. Control the spray humidification module; S4. Control the ambient humidity; The humidity value transmitted to the central control unit by the wireless transmission module is compared with the target value. When the current humidity is lower than the target humidity value, a signal is sent to control the opening of the spray humidification module. The signal is then sent from the wireless transmission module to the wireless receiving module to control the opening of the nozzle device. When the current humidity is equal to or greater than the target humidity value, the central control unit sends a signal to close the spray humidification module, and the local control box closes the nozzle device.

2. The method for improving pantograph-catenary wear in subway trains during winter, as described in claim 1, is characterized in that... The target humidity level is set to a lower limit of 55%RH.

3. The method for improving pantograph-catenary wear in subway trains during winter, as described in claim 1, is characterized in that... Inside the subway train tunnel, a humidity sensor is selected as the measurement point for tunnel humidity. The humidity sensor is installed on both sides of the tunnel wall. The humidity sensor detects the humidity in the tunnel in real time and transmits the data to the central control console via a wireless transmission module. The humidity sensor is then compared with the target humidity to control the spray humidification module.

4. The method for improving pantograph-catenary wear in subway trains during winter, as described in claim 1, is characterized in that... The spray humidification module is located in the tunnel and controls the humidity.

5. The method for improving pantograph-catenary wear in subway trains during winter, as described in claim 4, is characterized in that... The spray humidification module is a tunnel foam-water spray combined system. The nozzles are installed on the tunnel sidewalls, and the spray humidification modules are placed at an average interval of 400m to 500m.

6. The method for improving pantograph-catenary wear in subway trains during winter, as described in claim 5, is characterized in that... Each of the spray humidification modules is equipped with 5 nozzles, which are oriented diagonally upwards, with a nozzle spacing of 5m and an installation height of 12.75m.

7. The method for improving pantograph-catenary wear in subway trains during winter, as described in claim 1, is characterized in that... Step S4 specifically involves comparing the data detected by the subway train humidity measurement sensor with the target humidity value of the environment. When the humidity is lower than the target humidity value, the device activation information is sent to the wireless receiving module, and the local control box activates the nozzle. When the data detected by the subway train humidity measurement sensor is higher than the target humidity value, the local control box controls the nozzle to shut down.

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