Ceramic insulators have excellent insulation properties, weather resistance, heat resistance and assembly flexibility, and are widely used in various voltage levels. However, Disc-shaped porcelain insulators are fragile.
Glass insulators have zero-value self-explosion characteristics. Self-explosion is caused by impurities and nodules produced in the glass manufacturing process. If the impurities and nodules are distributed in the inner layer, the product will be manufactured within a period of time after the product is manufactured. Some will explode. Therefore, the manufacturer should store the product for a period of time after manufacturing to find the quality hazards in the manufacturing process.
If impurities or nodules are distributed in the outer compression layer, after a period of operation on the transmission line, under the action of the strong cold and heat temperature difference and electromechanical load, it may cause the glass insulation to explode.
In addition，during operation, after the glass insulator is wetted by the dirt layer on the surface, it is partially discharged under the action of the power frequency voltage. The long-term heating caused by partial discharge causes the insulating layer of the glass component to fall off, leading to zero-value self-explosion.
Therefore, the spontaneous explosion rate of glass insulators operating in heavily polluted areas will increase. However, the self-explosion rate of glass insulators is different from the degradation rate of porcelain insulators and the aging rate of composite insulators.
The self-explosion rate of glass insulators is early exposure. With the extension of operating time, the spontaneous explosion rate of porcelain insulators is decreasing year by year, while the deterioration rate of porcelain insulators is exposed later. With the extension of time, the degradation rate will be gradually increased by the action of the electromechanical composite load.
Due to the aging characteristics of organic materials, the aging rate and degradation rate of composite insulators will increase over time. It is generally believed that the aging life of glass insulators and porcelain insulators is about 50 years, and the aging life of composite insulators is less than 25 years.