On the Nonlinear Seismic Responses of Shock Absorber-Equipped Porcelain Electrical Components

Abstract

Porcelain electrical equipment is prone to brittle failure due to resonance under seismic effects. To improve its seismic resistance, some researchers have conducted research on shock absorption technology for porcelain electrical equipment. However, extant research fails to provide a detailed and systematic study of the effect of the nonlinear characteristics of these shock absorbers on the performance of equipment under seismic effects. This paper provides a theoretical analysis, verified by shaking table testing, of the performance of a 1000 kV pillar-type porcelain lightning arrester. The Bouc–Wen model is fitted to the force-displacement curve of hysteretic nonlinear metal shock absorbers, and a dynamic model of, and equations for, pillar-type porcelain electrical components are derived, taking into account their nonlinear characteristics. This reveals the influence of the nonlinear characteristics of shock absorbers on the nonlinear seismic response characteristics of these components. Our results indicate that the seismic responses of pillar-type porcelain components can be effectively suppressed by hysteretic nonlinear shock absorbers and that the greater the intensity of the seismic waves, the more obvious the efficiency of shock absorption. However, as the installation radius and yield force of the installed shock absorbers increase, their shock absorption efficiency gradually decreases.

Stochastic Response of Composite Post Insulators under Seismic Excitation

“…Let the stiffness of the bottom flange of the upper composite insulator be represented by id k , and the stiffness at the top of the lower insulator be denoted as ( 1) i u k -. The resultant stiffness of the composite insulator's two parts, denoted as i k , can be expressed as follows [19,20]: For a configuration of three post insulators, composite insulators are affixed with three flanges. Sections are joined by flanges, with one flange positioned at the upper end and another at the lower end of each connection (see Figure 4).…”

“…Let the stiffness of the bottom flange of the upper composite insulator be represented by k id , and the stiffness at the top of the lower insulator be denoted as k (i−1)u . The resultant stiffness of the composite insulator's two parts, denoted as k i , can be expressed as follows [19,20]:…”

“…Due to the non-stationary nature of ground motion excitation, the wavelet-Galerkin method [12] is employed to solve the response of the system (20), and the wavelet expansion of Equation ( 20) is performed:…”