Recently the company I work for had a few phase to phase issues and they are working out some new work practices, possibly requiring us to always get the feeder reclosing off and the high speed trip on whenever we are working hands on, on mainline feeder where there is no fuse protection. Some of this the operator can do from the control room, and some has to be done manually at the recloser itself or the substation, depening on where we are working on the circuit. Used to only have to do that when we were pulling wire, or at the crew leaders discretion. I was wondering what your guys utilitys rules are regarding the issue. (when you have to use it etc...)? There isn't even hardly a spark when the high speeds are on.
Ummmmmmm We usta hafta get any Feeder we were working on placed on oneshot, even if we were working behind fuses. the theory was that the breaker would operate before the fuse did.
anytime we are doing any work on the feeder the reclosure is off and a hold tag is placed. also when we are working behind any manual oil breaker it is by passed and the circuit put on one shot.
When you are doing hands on work it only makes sense to get a holdoff ( put the recloser on one shot). But remember a holdoff is to protect equipment only. The benefit for us is if there is a problem then the feeder just goes out. As for working behind fuses , I don't think its ok because the way a system is designed, when there is a fault, the breaker operates faster than a fuse blows. The purpose of fuses is to isolate a problem and allow the breaker to automatically reclose restoring the rest of the circuit. Most of the time reclosers are set up to operate 3 times then lock out. A holdoff simply means a lineman only gets electricuted once.
I'm sure the terminology is a little different between utiilites. We do use the K style fuse links. Used to be pretty much up to the crew leader as to whether to get the hot line tag (holdoff?) on or not but now they are requiring it, which seems to be more like the norm. Are you guys allowed to pick up any load with it on? (holdoff/hotline tag) I think it is a good thing, because it does protect equipment, as well as workers from possibly burns. The trip is super fast from what I hear.
We don't do nothing live unless the Feeder is set to one shot and tag placed.Funny story about this we were once completing a theory test to be re-authorised Live LIne and we all got the Q's wrong. It read why is the Feeder set to one shot? Now with us getting told "SAFTEY FIRST" every second of the day we all answered to protect the worker! BOM BO WRONG It's fundamently to proetct equipment. Needless to say we asked this of the manager and he was in the same thought path as us. Guess the dill's writing the test aren't savy with how we are drummed.I think it is a good thing, because it does protect equipment, as well as workers
IMO its a good idea to ask for a non test when ever you are working on the line, however even under the quickest operation of a breaker or Line recloser it still takes 3-5 cycles to operate and open, at a fault duty that could be in the thousands. At where I work we hardly ever have the OCB set faster than the fuses. Too many people complaining about resetting the clocks. So now the farther you are out on a circuit the faster the device operates, generally.
Why not put it on one shot? Even if it has a fast fuse on it? In fact, You don't know what kind of fuse is really in the barrel unless you go up and look. I think it's better to assume that the fuse won't blow and put it on one shot every time.