Mechanical galloping of overhead power transmission lines may cause flashover between lines and damage of insulator and tower. Existing models of galloping are not complete to simulate the galloping of three dimensional vibration coupling. In this paper, a three-degree of freedom model is suggested to account for the influences of environmental conditions, geometrical configurations and movement coupling properties. It can be deduced from the model that the power line galloping, with change of environmental conditions, may transit between activities of inertia coupling, vertical exciting and twisting inspiring, and the galloping amplitude is governed by the aerodynamic factors and coupling properties. The simulation results indicate that the galloping of transmission line can be limited by using air-flow-spoilers. The proposed model, simulation results and anti-galloping measures may be helpful for utilities to assess transmission line galloping performance and design of mitigating strategies.
Assessment of over-voltage in underground power distribution cables, due to lightning strikes impacting the earth's surface and terminating on the cable, is important in the design of suitable protection schemes and mitigating strategies. Existing models do not account adequately the effect of the characteristics of soil breakdown channels intercepted by the cable. In this paper: over-voltage in underground cable is investigated by considering the effect of the characteristics of soil breakdown paths predicted using a suggested model on an electric-$eld-related probabilistic basis. The model provides probabilistic information on the over-voltage in struck cables for different soil characteristics and geometrical configurations.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.