Correct option is D
Porcelain insulators generally have higher mechanical strength compared to glass insulators.
This makes them more suitable for applications where mechanical durability and resistance to physical stresses are important.
Porcelain insulators are also less likely to shatter under mechanical impact or stress, which is a common concern with glass insulators.
Porcelain insulators are known for their high mechanical strength, making them superior to glass insulators in this regard.
Porcelain is the most commonly used material for overhead insulators in the present day.
The porcelain is aluminum silicate. The aluminum silicate is mixed with plastic kaolin, feldspar, and quartz to obtain final hard and glazed porcelain insulator material.
The surface of the insulator should be glazed enough so that water should not be traced on it.
Porcelain also should be free from porosity since porosity is the main cause of deterioration of its dielectric property.
It must also be free from any impurity and air bubble inside the material which may affect the insulator properties.
Porcelain has a dielectric strength of 60kV/cm.
