For low voltage power transmission applications, a PIN type insulator is useful. However, when the voltage exceeds 33 kV, Suspension type insulators are recommended.
How Suspension Insulator Looks
The suspension type insulator comprises of number of porcelain discs that are connected in series by metal links forming a string.
How Suspension Type Insulator is connected
The transmission line conductor is suspended at the bottom end of the suspension insulator string while the top (upper) end of the insulator is secured to the cross-arm of the tower.
The figure below displays how it connects:
Suspension type insulators are commonly available in both forms:
- Porcelain type suspension insulators
- Glass type suspension insulators
Practically suspension insulators are useful for voltage values above 33 kV.