Composite insulators can take wind and rain and have good self-cleaning performance under wind and rain, so need checking for pollution only once every 4–5 years, and requiring less time for the repair and power interruption. Since the core rod has higher extension strength, composite insulators can result in very light overall weight. Their weight is only 10–20% of the weight of porcelain insulator strings of the same voltage class. Their length can be shortened by more or less 10% in the same voltage class, which can greatly reduce the labor of workers in transportation and field operation.
The composite insulator has many advantages, but also disadvantages, e.g., the loss of hydrophobicity, the risk of the core rod becoming brittle and breaking, lightning strike and birds droppings, which can all make composite insulators lose efficiency.
Since the diameter of the sheds of the composite insulator is less, the minimum electric arc distance is less than for the same length of porcelain insulator strings, and the lightning withstand level is also less than for the same length of porcelain insulator strings
After a lightning strike, the only effect on composite insulators is some white electric erosion; there is no change in their insulating property. But attention must be paid to the erosion of both ends of the fitting.
The internal insulation distance of composite insulators is nearly equal to that of the external insulation, and the structure is in the group of puncture-proof insulators, and therefore does not have the problem of having to detect zero value insulators, and this greatly reduces the workload of operation maintenance.
