Catenary-suspension type overhead line and method for setting pre-sagging

Abstract

To provide a catenary-suspension type overhead line capable of obtaining an optimal wiring form of a pre-sag wiring, improving power collection performance of a pantograph, and achieving stable high-speed traveling performance on a conventional line and a method for setting pre-sagging thereof.SOLUTION: A push-up locus on a trolley line by a pantograph is calculated by motion simulation of the trolley line on a railway line and the pantograph. A wiring form is set where a height position for each distance of 1 / 2 of a hanger interval from a support point of the trolley line with respect to the push-up locus is set to a position in which a root-mean-square error is minimum. Thus, the locus of a pantograph height becomes flat, preventing application of an inertial force. Therefore, the influence of a push-amount amount and a mass can be prevented irrespective of a difference in pantagraph type.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a method for setting pre-sag of a catenary-suspended overhead contact line in order to obtain stable current collection contact performance when electric railway vehicles are running. [Background technology]

[0002] In order to prevent contact wires on electric train tracks from coming off the wire, which would hinder the current collection performance of the pantograph, a "pre-sag" is added to the contact wire, which lowers the contact wire height in advance so that the support position of the contact wire can be adjusted periodically between support points to adjust the push-up force or amount of push-up. In this method of setting pre-sag, Patent Document 1 discloses that, based on a motion simulation of the pantograph locus in accordance with the target conditions of the running speed of the railway vehicle, the overhead contact structure, and the pantograph lift force, when the static height yS(x) of the overhead contact wire at position x is constant, yd(x), which is the pantograph locus obtained by applying a constant force equal to the pantograph lift force, is determined, and the static height of the overhead contact wire is set to yS(x)=-yd(x)+C using the value of yd(x) obtained. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2010-125973 DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0004] In the conventional pre-sag setting method, a constant contact force is applied using a motion simulation to determine the pantograph lift trajectory, and the contact wire height is set by subtracting this lift amount. However, because an actual pantograph has mass, the method only assumes a state where the constant contact force equals zero, which can result in the desired setting deviating from the actual situation. In high-speed trains such as the Shinkansen, where β (running speed / contact wire wave propagation velocity) approaches 0.7, applying the conventional method can result in the contact wire height changing at an acute angle, making it impossible to properly apply the axial force to the hanger. As a result, the hanger may float, preventing the desired height from being achieved, or the height adjustment may be difficult, resulting in maintenance issues. This method has therefore not been adopted in practice. In view of the above problems, the present invention aims to provide a catenary-suspended overhead contact line for electric railways and a method for setting the pre-sag thereof, which can achieve stable high-speed running performance on conventional lines by determining the optimal form of the pre-sag contact line. Summary of the Invention [Means for solving the problem]

[0005] In order to achieve the above-mentioned object, the present invention provides a catenary-suspended overhead contact line with an overhead contact configuration that minimizes the root-mean-square error of the difference between the trolley wire and pantograph's push-up trajectory and the trolley wire's push-up trajectory by the pantograph, based on a simulation of the movement of the trolley wire and pantograph on a railway track. In addition, a method was adopted in which the trajectory of the contact wire pushed up by the pantograph was calculated by simulating the movement of the contact wire and pantograph on a railway track, and the height position of each distance from the contact wire support point to the hanger spacing was set to a position that minimized the root mean square error on this push-up trajectory. [Effects of the Invention]

[0006] According to the present invention, the desired pre-sag can be easily achieved without being affected by the mass of the pantograph due to differences in type, and uniform improvement in current collection characteristics can be expected. Since the overhead contact wire configuration is symmetrical with respect to the center of the span, it can be applied to conventional railways that can operate in both directions, and the axial force can be appropriately borne by the hanger. [Brief explanation of the drawings]

[0007] [Figure 1] This is a model diagram of the spring-mass system of a catenary-suspended overhead contact line. [Figure 2] 10 is a graph showing the relationship between the mass of a pantograph and the displacement of an overhead wire. [Figure 3] 10 is a graph showing a comparison of overhead line configurations. [Figure 4] 10 is a graph showing a comparison of dynamic spring constants of different overhead line configurations. [Figure 5] 10 is a graph showing an example of calculation of the lift amount relative to the mass of the pantograph. [Figure 6] 10 is a graph showing a comparison of a push-up trajectory and a quadratic curve of sag under a constant push-up force. [Figure 7] 10 is a graph showing a comparison of the variation in pantograph height under the optimum sag by mass. [Figure 8] 10 is a graph showing a comparison of lift under optimum sag by mass. DETAILED DESCRIPTION OF THE INVENTION

[0008] A method for setting the presag of a catenary-suspended overhead contact line in an electric railway according to the present invention will be described in detail with reference to the drawings. One of the indicators for evaluating the dynamic characteristics of the contact wire and pantograph is the amount of contact wire lift caused by the pantograph. This amount of lift is determined by the pantograph lift force. The movement of the current collection system consisting of the contact wire and pantograph can be analyzed using the spring-mass system model shown in Figure 1, taking into account the inertial effect of mass on the amount of lift. Here, if the pantograph is a mass (mass) m, the lift force P0, and the contact wire is a spring k(x) (approximated by a cosine wave), the amount of lift (overhead wire displacement) y is given by the following equation (1).

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[0009] According to equation (1), the spring constant K is also a determining factor for the uplift y. The spring-mass model in Figure 1 is based on a constant overhead line height, but temperature changes and other factors in the actual installation environment can cause the overhead line to hog or sag, gradually changing the overhead line height. Sag can also be intentionally added to improve current collection characteristics at higher speeds. Figure 4 shows the results of a simple overhead line calculation comparing the spring constants at specific positions along the span (equidistant from the support point) for overhead line configurations with various hogs and sags, as shown in Figure 3. It can be seen from this figure that, regardless of the overhead line configuration, the spring constants are consistent under the same conditions of overhead line tension, hanger spacing, and span, confirming that a unique spring constant can be determined. The calculation was carried out using a simulation of the movement of the overhead contact line and pantograph, and was determined from the ratio to the calculated lift amount under the condition of a constant lift force.

[0010] If the lift force, mass and spring constant are determined, the lift amount can be determined uniquely. In various types of overhead contact lines, such as simple overhead contact lines, under the conditions in Table 1 (lift coefficient = 4 × 10-4 [N / km 2]), the above motion simulation was used to calculate the amount of lift, and an example of a constant overhead line height and 60mm sag is shown in Figure 5. For a constant overhead line height, "the greater the mass, the greater the amount of lift." On the other hand, for a 60mm sag, "the greater the mass, the smaller the amount of lift." The amount of lift varies depending on the overhead line configuration, but it is expected that there will be overhead line configurations that will achieve a constant amount of lift that increases and decreases reversibly. That is, when m = 0 (constant uplift force), the amount of uplift is constant regardless of the overhead line configuration, and mass is not involved. If the "sag corresponding to the uplift trajectory under the condition of constant uplift force" is used, the amount of uplift will be the same regardless of the overhead line configuration and mass. The uplift trajectory does not follow a quadratic curve and does not match the sag curve (x-axis symmetrical to the catenary quadratic curve). Therefore, as shown in Figure 6, the difference between the two is considered to be an error every 2.5 m (half the hanger spacing) from the fulcrum, and the curve that minimizes the root-mean-square error is determined to be the optimal corresponding sag. In this embodiment, the corresponding sag calculated was 47 mm.

[0011] The calculation results for the amount of lift using the above motion simulation, with the corresponding sag set to 47 mm, are shown in Figure 7. From this figure, it can be confirmed that even if there is a difference in mass, the value is almost the same as for a constant amount of lift (mass m = 0). Similarly, with the corresponding sag set to 47 mm, the calculation results for pantograph height using the above motion simulation are shown in Fig. 8. It can be seen from this figure that even with differences in mass, the pantograph height remains roughly constant and the trajectory is flat, resulting in no apparent inertial force and no effect of mass. On the other hand, the above motion simulation confirmed that when the overhead contact line configuration is smaller than the corresponding sag (including hog and constant height), the pantograph height traces a convex trajectory and an upward inertial force acts, whereas when the overhead contact line configuration is larger than the corresponding sag, the pantograph height traces a concave trajectory and a downward inertial force acts. This result is consistent with the characteristics obtained from the "spring-mass system model."

[0012] As described above, (1) the amount of lift is affected by the pantograph mass and the overhead contact line configuration, in addition to the lift force and spring constant. Even if the static lift force (the constant lift force that the pantograph exerts on the overhead contact line when the vehicle is stopped) and the spring constant are equal, depending on the overhead contact line configuration in which an upward or downward inertial force acts, the amount of lift will be greater the larger the mass, or less the mass, respectively. (2) Under the setting condition of "appropriate sag," the trajectory of the pantograph height becomes flat and inertial force does not act. Therefore, the mass does not affect the lift amount. In other words, the sag can be determined unambiguously regardless of "differences in pantograph type." (3) The root mean square error method is effective for setting the appropriate sag.

Claims

1. A catenary-suspended overhead contact line characterized by a contact line configuration that minimizes the root mean square error of the difference between the contact wire and pantograph's push-up trajectory and the contact wire's lift trajectory by the pantograph, based on a simulation of the contact wire and pantograph's movement on a railway track.

2. A method for setting the pre-sag of a catenary-suspended overhead contact line, characterized by calculating the trolley wire push-up trajectory caused by the pantograph through a motion simulation of the trolley wire and pantograph on a railway track, and setting the height position of this push-up trajectory at a distance of half the hanger spacing from the trolley wire fulcrum to a position that minimizes the root mean square error.

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