A. at dead ends
B. at intermediate anchor towers
C. flash overvoltage
D. any of A or B
B. at intermediate anchor towers
C. flash overvoltage
D. any of A or B
Answer: D. any of A or B
Explanation:
- When suspension string is used to sustain the extraordinary tensile load of conductor it is referred as string insulator.
- When there is a dead-end or there is a sharp corner in the transmission line, the line has to sustain a great tensile load of conductor or strain.
- A strain insulator must have considerable mechanical strength as well as the necessary electrical insulating properties.
- Strain insulators are generally used up to 33 kV line. These insulators should not be fixed below three meters from the ground level.
Rated System Voltage VS Number of disc insulator used in strain type tension insulator string
33KV----3
66KV----5
132KV---9
220KV---15
Rated System Voltage VS Number of disc insulators used in suspension insulator string
33KV-----3
66KV-----4
132KV----8
220KV----14