Auto reclosing 1

[samreen]

Do we need to block Auto reclosing when eitherSoTF or Stub protection operated if yes why?

 

[davidbeach]

It depends. What do you want? SOTF means that you have closed into a fault on an unenergized line; do you want to try it again? Stub bus protection trip says that you have a bus fault; do you reclose for bus faults?

 

[rngtrtl]

I agree with David, and it depends on the voltage level. 69kV+ I would never auto reclose for a bus fault. Same for for a SOTF. 9 times out of 10 (at least what I have seen) a SOTF arrises when the field forgets to pull the ground chains off the lines after working on them and then close the breaker which results in a bolted 3 ph fault. So I would drive to lock out and not reclose for a SOTF.

 

[marks1080]

Short answer YES.

 

[davidbeach]

marks1080, if it were that easy, I'd have responded with a yes. We don't worry about lightning to the point of not shielding lines; somebody I know who cut his teeth doing protection in Florida says they'd regularly do a single single reclose on bus faults because they'd have so many false bus diff trips from close in lightning strikes. If you'd normally reclose on bus faults you'd also reclose on a stub bus fault.

Not sure why anybody would reclose following SOTF, but they might, say if you have multi-shot reclosing and get SOTF on anything other than shot 0 you might want to go ahead and allow subsequent shots but block reclose for SOTF on shot 0.

No one size fits all answer.