1、 The influence of impurities and nodules during the manufacturing process
Impurity distribution: During the manufacturing process of glass insulators, if there are impurities or nodules in the glass body, these defects will disrupt the stress balance inside the glass. Especially when impurities are distributed in the inner tension layer, they can cause self explosion in a relatively short period of time (30-60 days), which is usually judged as self explosion caused by manufacturing reasons.
Stress concentration: Impurities can easily form tensile stress zones around them, leading to stress concentration. This stress concentration phenomenon can easily cause breakage of glass insulators when subjected to external forces or temperature differences.
2、 The role of impurities and temperature differences during operation
Impurity distribution changes: During operation, if impurities in glass insulators are distributed in the external tension layer and encounter a temperature difference between hot and cold (especially when suddenly cooled), under stable mechanical load, self explosion will occur within 1-2 years, which is usually judged as a quality related self explosion during operation.
Temperature difference stress: Glass has poor thermal conductivity. When the temperature changes sharply, there will be a large temperature difference between the inner and outer layers, which will cause a difference in shrinkage stress. If the temperature difference stress exceeds the stress that glass insulators can withstand, it will cause self explosion.
3、 Surface pollution and partial discharge initiation
Serious pollution accumulation: If the surface area of tempered glass insulators is severely polluted during operation, it can cause partial discharge or single piece creepage after being dampened, leading to heating and insulation degradation.
Self explosion determination: This type of self explosion caused by accumulated pollution and partial discharge is usually determined as a zero value self explosion. It reflects the performance degradation process of glass insulators in harsh environments.
