Aerodynamic instability of long-span transmission lines

Abstract

A. Simpson, Dip.Tech.(Eng.), Ph.D. Synopsis«/r = current yaw anglê o = y a w angle of steady wind CT = mass per unit length of cable £ £ j £ 0 = even and odd functions, respectively, of s/S, vanishing at s/S = ± 1 (x) v , cj z = 27rf 0 , =2irf z (circular frequencies of in-plane and lateral modes, respectively)

Analysis of High Codimensional Bifurcation and Chaos for the Quad Bundle Conductor's Galloping

“…where 𝑓 (𝑞 0 (𝑡 − 𝑡 0 )) = (𝑦 20 , 𝜇 1 𝑦 10 − 𝑦 3 10 ) 𝑇 and 𝑔(𝑞 0 (𝑡 − 𝑡 0 ), 𝑡) = (0, 𝑢 2 𝑦 20 − 𝑦 2 10 𝑦 20 ) 𝑇 . Here the wedge product is defined by 𝑎 ∧ 𝑏 = 𝑎 1 𝑏 1 − 𝑎 2 𝑏 2 .…”

“…It can cause disruptions of the electrical supply and even can lead to a cascading collapse of supporting towers, just like the snow disaster happened in the south of China in 2008. Although galloping has been extensively investigated since at least the 1930s and some important results have been obtained, for example, by Den Hartog, [1] Simpson, [2] Blevins and Iwan, [3−4] and Yu et al, [5−9] this problem has not been resolved satisfactorily. One reason for this shortcoming is that the model was constructed based on a single conductor, but not on a bundle conductor, [10−13] which can be more suitable for actual situations.…”

Separated and unsteady flows in aeronautics: Research at the University of Bristol

“…Ref. 5). A span can develop pendulum style oscillations in the critical Reynolds number range, where the relatively low velocity but high drag when moving downstream puts more energy into the cable than is taken out by the relatively high velocity but low drag when moving upstream (see Fig.…”

Transverse aeroelastic instability of guard cables with beacons excited by a longitudinal wind

“…In a first approach, one of the possible candidate phenomena considered responsible for the aerodynamic loading leading to instability was galloping in one of its several forms. In this regard, different types of galloping of overhead transmission lines or other long span cables were reported and analyzed experimentally or theoretically by Davis et al (1963), Simpson (1965), Dale et al (1968), Bartoli et al (2006), Macdonald and Larose (2006), Macdonald et al (2008), Hung and Yamaguchi (2014) and Zhou and Liu (2015).…”