Suspension type insulator
Suspension type Insulators diagram:
Suspension type Insulators
Because of limitations of pin type insulators for higher voltage, suspension type Insulators are used. Suspension type insulator consists one or more insulator unit connected together to form a string and hanged to the cross arm of supporting structure or tower and carry power conductor at its lowest extremity. This type of composite unit also called as string type insulator.
The conductor is suspended at the bottom end of the string while the other end of the string is attached to the cross arm of the supporting structure.
In suspension type insulator each disc of porcelain is designed to operate at 11KV, as operating voltage increase number of disc connected in series increases. e.g 132 KV transmission the number of insulator disc required is 12. Suspension type insulators can be used for higher voltages which is not possible in case of pin type insulators.
Advantages of suspension type insulator
- Suspension type insulator being economical as compared to pin type insulator for high voltage overhead transmission line
- Each insulator disc is designed to operate for 11KV. hence for any operating voltage, a string of insulator can be used. for example, for 66kv 6 number of discs are required.
- In case of failure of one of the units in a string, only that unit/disc need to replace rather than the whole string.