Power0020
Electrical
- Jun 11, 2014
- 303
Seems a bit academic but the effect of multiple insulators in parallel in increasing the falshover probability is well documented in many papers ( Clause 2.3)and this is the reason that a transmission line is usually having a lower insulation level than a substation (in addition to the fact that a substation is more critical than a line, by design).
As such, the parallel insulators within a line or substation subjected to a lightning surge may have a probability of flashover higher than that dedicated by BIL, traditionally set at 10% or in other words, the BIL of an insulator is not what we get for a bus with say 10 parallel insulators, but rather a level less than the individual insulator BIL.
Not sure if any of you came across this type of information on practical aspects or failures that took place with voltages lower than BILs?
As such, the parallel insulators within a line or substation subjected to a lightning surge may have a probability of flashover higher than that dedicated by BIL, traditionally set at 10% or in other words, the BIL of an insulator is not what we get for a bus with say 10 parallel insulators, but rather a level less than the individual insulator BIL.
Not sure if any of you came across this type of information on practical aspects or failures that took place with voltages lower than BILs?