Effects of Time-Varying Mass on Stability of High-Voltage Conductor in Rain–Wind Condition

Abstract

Although unanticipated low-frequency vibrations frequently happen on high-voltage conductors under the simultaneous occurrence of wind and rain, the source of these vibrations is not well known. Many studies focus on the impact of rain loads on the high-voltage conductor but very few examine the effects of time-varying mass. Raindrops hitting high-voltage conductors may partially stay on their surface and form rivulets or ridges. As the adhered raindrops may be blown or shaken off, the mass of the rivulets will vary with time. In order to investigate how the time-varying mass of the rivulets affects conductor motion, an analytical model with time-varying mass is established, which leads to the statement of an instability criterion. The vibration characteristics and instability of a high-voltage conductor with fixed and movable rivulet are discussed. The results show that the time-varying mass ratio may affect the peak vibration amplitude, and the unstable zone of the conductor with moveable upper rivulet is much wider than that with fixed upper rivulet, and the rain–wind-induced vibration occurs more easily than Den Hartog galloping. Such comparative studies may prove valuable as they enhance the understanding of the mechanism of the rain–wind induced instability of the high-voltage conductors.