Modeling combined friction-viscous damping in response of hollow core composite insulators

Electric power substation systems are critical facilities as lifeline systems for sustaining society from earthquake events. The composite hollow core electrical post insulators are important parts of the electrical substations equipment and their failure may have consequences to the local network and to the entire grid. In this study, a macroscopic analytical model is developed, which consists of gravity mass, two linear springs, viscous damping, and friction characteristics. The macroscopic model is formulated with high order differential equations derived with a state-space form solved by using Runge-Kutta method. Several prototype insulators have been tested at the University at Buffalo and the developed models are verified through comparing with the test results. The comparisons of acceleration and displacement responses are conducted and show good agreements.