Dynamic load on composite insulators using in UHVDC lines due to conductor galloping

Due to the excellent anti-pollution and dielectric characteristics, composite insulators have become a good choice for the outdoor insulation of transmission line, especially high voltage grade line. Since the electrical properties of composite insulators have been widely accepted, for the application of composite insulators on UHVDC transmission projects, the mechanical property is the key problem. How to obtain the dynamic loads under galloping is of the line designers' major concern, for galloping often occurs in overhead transmission line and does great harm to the insulator. In this paper, basing on UHVDC lines consisting of composite insulators, a mathematical method was proposed to calculate the dynamic loads due to conductor galloping both on V-type strings and tension strings by establishing the finite element model of the transmission line and the galloping simulation model. Relationship between the galloping amplitude and the dynamic load was demonstrated. Furthermore, the dynamic amplification factor of dynamic peak loads relative to their corresponding static loads was summarized and then was compared between the two kinds of insulator strings. The present research in this paper can provide certain theoretical foundation for the selection of UHVDC insulator strings consisting of composite insulator, promoting the process of applying composite insulators on UHVDC lines.