Static Mechanical Characteristics Study of Cap and Pin Insulator at Low Temperatures

There have been lots of failure accidents of cap and pin insulator when it is at extremely cold environment. The research object of this paper is cap and pin insulators of porcelain and glass with different rated mechanical damage road. And the experiments to test their static mechanical characteristics are carried out at low temperatures. The results show that with the decrease of temperature, the mechanical strength of insulator metal fittings, insulation parts and cement adhesive are improved in varying degrees. However, with the decrease of temperature, the size of metal accessories and insulators does not change much. The results show that the shrinkage degree of cement adhesive volume with the decrease of temperature is higher than that of other connecting parts. According to the analysis, the cavity between the insulator and the iron cap caused by the shrinkage of cement adhesive is the main reason for the failure of mechanical characteristics. For the sake of operation safety, it is suggested that insulators with mechanical strength higher than the design value should be used to reduce the probability of mechanical failure of insulators caused by adhesive cavities.