Precise Measurement and Estimation Method for Overhead Contact Line Unevenness

Abstract

The unevenness of contact lines is one of the factors that considerably influences on the dynamic characteristics of current collection system. In order to analyze the influence of the contact line unevenness on the fluctuation of the contact force between contact line and pantograph, an instrument was devised to measure the unevenness of contact lines accurately and continuously. The instrument consists of two pairs of laser sensors for the purpose of reducing measurement errors by the vertical vibration of measurement vehicle. This paper describes the measuring method of contact line unevenness, reports some examples of the measurement of real lines, and proposes a method to evaluate the conditions of overhead equipment.

Advances of research on high-speed railway catenary

“…Bohol and Houmei [127] analyzed the wave-like wear pattern measured from the Shinkansen in Japan and its correlation with contact loss. Aboshi et al [124,128] established the power spectral density (PSD) of the contact wire irregularity of the Shinkansen and analyzed the pantograph-catenary contact force affected by the irregularity. Zhang et al [54] studied the influence of contact wire irregularity on the contact force using a hardware-in-the-loop test rig and synthetic wire height and identified some critical irregularity wavelengths.…”

Installation Guidelines for Shinkansen High Speed Overhead Contact Lines

“…The "installed condition" information consists of data from 44 Shinkansen high speed sections collected via a device to measure unevenness [3]. As shown in Table 1, data concerning six types of overhead contact lines were included.…”

“…Contact force fluctuation factors have been reported as follows; ① periodic motion of the pantograph during support point intervals (span) [1], ② periodic motion of the pantograph in hanger spans [2], ③ unevenness of the overhead contact line (change in contact wire height) [3]. The mechanisms of the first and second factors are almost clear, and improvement methods for Shinkansen high speed operations with respect to these factors have been presented in previous studies.…”

“…Converting (1) the origin at the pantograph point and using boundary conditions at that point, the contact force fluctuation of the pantograph is expressed by (2) [3] where i is imaginary unit, Z t , Z p are the mechanical impedances of the overhead contact line and the pantograph respectively.…”

“…In reality though, some unevenness of around tens of mm exists due to imprecision during installation at the support points or because of irregularity around hanger points. Figure 2 shows the relationship between estimated unevenness values on a section of Shinkansen line and the contact loss ratio of pantographs running in this section [3]. The estimated unevenness value is expressed by the standard deviation of the contact force fluctuation derived from (2), in other words, it expresses the degree of the unevenness of the overhead contact line.…”