(1) The influence of temperature, temperature has a great influence on the insulation resistance, and the insulation resistance decreases as the temperature rises. The reason is that the temperature rises, the polarization of the insulating medium increases, and the increase in electrical conductivity causes the insulation resistance to decrease. The reason for the change is related to the degree of temperature change and the nature and structure of the insulating material.
(2) The influence of humidity, humidity has a greater influence on the surface leakage current, because the insulating surface absorbs moisture and forms a water film, which will significantly reduce the insulation resistance.
(3) Deterioration caused by insulator mechanical overload.
(4) The hygroscopicity of porcelain parts deteriorates.
(5) Overlap of internal and external stress of porcelain parts deteriorates.
(6) Deterioration caused by thermal expansion of porcelain insulators.
(7) The saturation expansion of steel cap pouring cement deteriorates.
(8) The freezing expansion of the steel cap pouring cement deteriorates.
(9) The electric corrosion of the steel cap and steel feet deteriorates.
(10) Deterioration caused by insulator overvoltage.
(11) Deterioration caused by internal defects in the insulator.