A study of mechanical and electrical properties of aged, heat-shrinkable tubes

It mainly depends on the anti-aging performance whether heat-shrinkable tubes for busbar can maintain excellent electrical and mechanical properties during long term operation. In this paper, the samples were applied to the switchgear busbar of 10 kV and 35 kV in substations of Tianjin Power System. Their operating time is 0, 1, 2, 9 years and 0, 4, 6 years respectively. Tensile strength (breaking strength, elongation at break), dielectric permittivity, dielectric loss tangent, AC impedance and breakdown characteristics under AC voltage are tested. The result shows that the tensile strength decreases while dielectric permittivity and loss tangent increase with the operating time. The decline of breakdown strength and AC impedance indicates that insulation capability is reduced by long time natural aging.