Study On Sealing Failure Characteristics Of Inflatable Composite Cross-Arm And Its Influence On Internal Insulation Characteristics

Composite cross-arms had received widespread attention in the industry for its unique electrical and mechanical properties.For composite cross-arms filled with barotropic gas,its sealing characteristics and internal insulation properties are essential for the safety and stabilization of the power grid.Composite cross-arms have to withstand complex climatic environments,mechanical loads and voltages.If sealing performance of the composite cross-arm deteriorates,it may causes flashover,threatening the safety and stabilization of the power grid.In this paper,the sealing failure characteristics of the composite cross-arm under mechanical vibration,the influence of moisture intrusion on the internal flashover characteristics,and the analysis of the leakage current characteristics are studied.The main results are as follows:This paper simulated the stress of the composite cross-arm when it works.Through long-term vibration tests,the sealing failure characteristics of the composite cross-arm were studied.Studies had pointed out that with the increase of the vibration time,the air pressure inside the composite cross-arm decreased suddenly at a certain moment,and the sealing failure caused the air pressure to leak.The main causes of seal failure were due to the loss of backfill plugging ability of the seal ring and the loosening of the flange bolts.Considering the consequences of the sealing failure,this article explored the effect of moisture intrusion on the internal flashover characteristics of the composite cross-arm.Studies had showed that temperature had a small effect on the internal insulation of inflatable composite cross-arm.Under good sealing conditions,the composite cross-arm could maintain insulation performance at various ambient temperatures.The internal absolute humidity significantly affected the internal flashover characteristics of the composite cross-arm.The increase in the absolute humidity caused the internal average flashover voltage to decrease.Condensation occurs on the inner wall surface when temperature and humidity work together,and the state of the dew on the inner wall surface was different under different temperature and humidity conditions.In this paper,the statistical analysis of the leakage current characteristic on the inner surface of the composite cross-arm under the corresponding temperature and humidity conditions was shown.The increase in humidity caused the condensation and the leakage current increasing.The increase in temperature made the surface dry,but the amplitude of the leakage current increased with the influence of the material conductivity.Due to the differences in the internal surface conditions at different temperatures and humidity,there were some differences in the development process of flashove.