Research on the Influence of Multiple Opening and Closing Operations on Tensile Properties of Insulation Pull Rod for GIS Circuit Breaker

The insulation pull rod for GIS circuit breaker is mainly subjected to axial external force when it is operated. Generally, the axial tensile force during opening is the maximum external force that the insulation pull rod bears during operation, so its tensile properties can best reflect the mechanical performance. Moreover, GIS circuit breaker need to be operated frequently, and its insulation pull rod usually has a mechanical life requirement of tens of thousands of times. So the tensile properties of insulation pull rod after multiple opening and closing operations has an important impact on the long-term safe and reliable operation of GIS circuit breaker. In this paper, through the simulated operation test and static tensile experiment, the tensile properties of hollow tubular insulation pull rod used in 220kV GIS circuit breaker made of glass fiber reinforced epoxy resin composite after different times of simulated operation are studied. The experimental results show that the tensile failure mode of the insulation pull rod after different operation times is all the bolt hole of the side metal part of the mechanism breaks. Before that, the adhesive interface of the insulation pipe and the metal parts has been partially peeled off. Moreover, multiple opening and closing operations will reduce the tensile modulus of the glass fiber reinforced epoxy resin composite and the tensile strength of the adhesive interface between the insulation pipe and the metal parts, which will cause local peeling when it bears a smaller tensile force then a new one, and also affect the overall tensile failure value of the insulation pull rod.