The porcelain station post insulators are an important part of power transformation equipment in power station and transformer substation, which play the role of supporting wires and insulation. In recent years, there have been many fracture accidents in the power station and substation in China's power industry, causing damage to the porcelain station post insulators
in the service, which will bring harm to the normal operation of the power transmission and transformation system as well as the safety of people's lives and property. So it is necessary to strength the security management in this area.
The working environment of the porcelain station post insulators
is very harsh. Due to many external factors (such as rain, snow, strong wind, ice coating, sun exposure and so on), the additional stress of insulators is high. In addition, the porcelain station post insulators, which are fired at a high temperature, is a kind of brittle material with low toughness. For example, if there are defects in the internal microstructure of porcelain station post insulators such as the insufficient strength, it is likely that stress concentration occurs at some defect position, especially at the surface, resulting in the instability and propagation of microcracks, which will eventually lead to the fracture failure. In addition, the porcelain station post insulators can be affected by many factors such as the difference of natural temperature and the calorification of conductors during operation, and they will also withstand the test of large temperature difference. Under the thermal stress caused by such change of temperature, the microcracks in the insulators may also be unstable to become expanding, which will seriously affect their service lives. Therefore, it is necessary to grasp the key factors which affect the intrinsic quality of porcelain station post insulators from the aspects of composition, organization structure and performance.