Advantages: 1. The glass insulators have higher resistance to breaking comparing to the ceramics and its mechanical compressive strength is 1.5 times higher than ceramics. 2. The electrical resistance is much higher than that of ceramic insulators (between 500 kV/cm and 1000 kV/cm). 3. The thermal expansion coefficient of glass insulators is small, and its relative deformation is very low due to temperature variation. Also, glass insulators before cracking are completely crushed, so it is easy to detect faulty insulators on the floor. Contrary to ceramic insulators, any crack or hole created during the manufacturing process is detectable in the glass insulators. 4. Due to transparency, some sun rays pass from the glass insulator, thereby decreasing the degradation of the insulator. Disadvantages: 1. The mechanical durability of glass insulators against bending forces is slightly less than that of ceramics. 2. With a strong impact all insulators will break. 3. Any impurity in composition or any temperature variations of the environment during storage or operation leads to breaking the insulator. 4. The glass insulators absorb contaminations easier than other types of insulators. 5. The moisture is easily distilled on the surface of the glass insulators.
