re-fusing urd bayonet fuse

[reppy007]

Ok,since summer time is here,and some urd pots will be getting overloaded........what proceedure will you follow when you are re-fusing a bayonet fuse.....will you open the loop first.....refuse and pick the transformer up at the fuse or will you try the fuse while the primary is still hot?......we usually had the choice,but most guys wouldnt bother with the fuse........If I was running trouble,I usually would head to that call about an hour later.......giving the transformer time to cool off.......now just a small tip,carry an extra bayonet on your truck.....some do burn into......what proceedures do you use?

[Lineman North Florida]

We don't have any left, but we used to vent the transformer and try it with the fuse if there wasn't anything obvious on the secondary side or meter cans etc.

[reppy007]

You dont have any left.......transformers or bayonet fuses?

[Lineman North Florida]

You dont have any left.......transformers or bayonet fuses?

Surely I don't have to answer that. We have no padmount transformers left with bayonet fuses, phased them out thru the years.

[reppy007]

[QUOTE=Lineman North Florida;127235]Surely I don't have to answer that. We have no padmount transformers left with bayonet fuses, phased them out thru the years.

I see,so you have the switch like a csp or?Was there some type of problem with the bayonet types,or just a new brand.......that surprises me.it would about take a lifetime to phase the ones out over here,

[T-Man]

We would never re-energize a PMT with the fuse standing in front of the can. we would close the loop if there was one and open the primary, one tub away and refuse at the tub that was out, then close from the remote location. if all went well then open the loop again. If it was radial then we would kill the primary one tub away and do the same, only there would be a few more customers in the outage.

If we had a tub that was working and we pulled the fuse to get work done on the secondary, like add a new main or service, as long as the tr was good to start we would refuse it right there, only we would use a shotgun stick from the side incase the fuse launched and the tub spewed oil in the process.

[Pootnaigle]

Ummmmmmmm I always did it from the side witha shotgun also. It wasnt often that one would blow a bayonet fuse as I think they were either overfused or used the wrong fuse curve for our system anyway.More often than not they would allow the dip fuse to operate first.

[CPOPE]

I would not close in on a suspected fault. Energize remotely per manufactures recommendation.

http://www.cooperindustries.com/content/dam/public/powersystems/resources/library/240_Fusing/S240403.PDF

[reppy007]

T-MAN,did I understand you correctly,you guys pull the bayonet while hooking up services,so yall dont work them hot?

[Bighorn Ape]

So basically the goal is to NOT be near the potentially faulted TX while heating it back up? ( the next TX up, or like some mention to do it on the riser pole)

Underground rookie :)

[reppy007]

Since we are discussing urd,I dont know if anyone has seen it done,but Ive seen contractors injecting some type of chemical into the primary at the transformers,mostly old wire that has been there for awhile,never thought to ask the crews exactly what it does,and would have my doubts anyway,but can anyone explain the why question.......kind of like putting heat shrinks below the elbow,keeping moisture out,now its done with cold shrinks at some places.......does it really do the wire any good?

[lewy]

I have never pulled a bayonet fuse live, or installed one. We hook up our secondary's live in single phase transformers. If the fuse is bad we would test the transformer first with a Hastings transformer tester than re energize with the elbow or transformer switch on the newer ones. LNF I am curious as to why you guys phased out the bayonet fuses (we are talking the oil immersed not the dry canister type)? Did not know that was an option.

[T-Man]

T-MAN,did I understand you correctly,you guys pull the bayonet while hooking up services,so yall dont work them hot?

Yes, if you pull the fuse the tub is de-energiszed and the primary feeds thru. we wore rubber gloves while installing or removing the secondary lugs.

[reppy007]

Not often did we suspect a fault on the secondary side,usually we re-fused them during the summer,and almost always it was cause it was overloaded,on a bad evening you could have 3 or 4 that were out,so we would refuse them,and hope they held,like it was said before re-fusing we would bleed them off by pulling the pressure valve,and standing to the left side while re-fusing..........now the un-written rule was to open the loop and do your thing,,,,,,,and close the loop to energize it,,,,,,if fire were to occur it would be contained inside the pot instead of blowing out into the customers yard......but like I said,the rule wasnt in stone and I saw only one guy do it that way.

[Lineman North Florida]

I have never pulled a bayonet fuse live, or installed one. We hook up our secondary's live in single phase transformers. If the fuse is bad we would test the transformer first with a Hastings transformer tester than re energize with the elbow or transformer switch on the newer ones. LNF I am curious as to why you guys phased out the bayonet fuses (we are talking the oil immersed not the dry canister type)? Did not know that was an option. I didn't realize that the bayonet fuse type padmounts were still widely used as around here most company's have gone to padmouts with internal weak link fuses, I can't speak for why, probably cost if I had to guess, as someone stated earlier I haven't seen them work very well, the fuse on the loop or radial would usually operate before the bayonet fuse did.

[Lineman North Florida]

Since we are discussing urd,I dont know if anyone has seen it done,but Ive seen contractors injecting some type of chemical into the primary at the transformers,mostly old wire that has been there for awhile,never thought to ask the crews exactly what it does,and would have my doubts anyway,but can anyone explain the why question.......kind of like putting heat shrinks below the elbow,keeping moisture out,now its done with cold shrinks at some places.......does it really do the wire any good? We have some in-house crews injecting some of our older direct buried cable, a company called Novinium I believe is working with them on the injection process, it is supposed to extend the life of the cable upwards of an additional 20 years they say, true or false, I don't know. The way I understand it is after the injection process each cable gets a tag put on it with an indivdual number for tracking the injection process, if that cable fails within X number of years after the injection process you turn that tag in and the company gets re-imbursed for the cost of the original injection, I do know that a few cables will not tolerate the injection very well and will burn out within a few days, we had one a few weeks ago that after injection had 3 burnouts in a week, so it had to be replaced. I wish I could tell you a little more about it, but that's about all I know, we mostly do overhead on our side the company.:D

[T-Man]

I didn't realize that the bayonet fuse type padmounts were still widely used as around here most company's have gone to padmouts with internal weak link fuses, I can't speak for why, probably cost if I had to guess, as someone stated earlier I haven't seen them work very well, the fuse on the loop or radial would usually operate before the bayonet fuse did.

In the middle of the 80's the tubs we were getting had a current limiter inside the tub in line with the bayonet fuse. If you had a tub with a blown CL all you could do is replace the tub all together. If just the bayonet fuse blew you could replace that either remotely energizing when there was a suspected fault or off to the side when the fuse was pulled on a good tub for some work done on the secondary.

[Pootnaigle]

Ummmmmmmm If I remember right they inject that blue goop into an isolated span of cable and its spozta extend the life of the cable .It often fails at any splices in the cable, and causes an outage once its returned to service.

[reppy007]

Ummmmmmmm If I remember right they inject that blue goop into an isolated span of cable and its spozta extend the life of the cable .It often fails at any splices in the cable, and causes an outage once its returned to service.

Blue goop,hahaha I guess thats a good word for it,that subject came up.......would it go through a splice,i never did ask,afraid they would tell me that it did.......wonder if they sometimes put a couple of drops of blue goop and thought it would go through a whole span...........really I wonder if it really worked at all..........I know those metal plates they install on rotten poles seem to be ok,the ones that are around 10 feet long and are heavier than 20 fat guys.......the ones that you have to jack out of the ground with a steel sling.

[Lineman North Florida]

The way I understand it the blue goop that ya'll are referring to will not go thru a regular splice, if there has been a burnout in the cable and it has been spliced it has to be dug up and replaced with one of their splices that will allow the "stuff" to flow thru it, whether the "stuff" works or not who knows, but the positive side that I see to this procedure is just the fact that you are going to a transformer that is already really old and isolating the cables,#1 any numbering issues should be caught and corrected at this point,#2 the elbows on the cables have to be replaced to allow for the injection,#3 if the transformer is leaking or rusted out etc,etc, it can be replaced,#4 all of your other equipment ie" secondary pedestals, primary splice pits etc will be looked at while you are in the neighborhood and replaced if necessary, prior to this program getting started all we did was re-act to problems on a URD loop or radial, I consider this pro-active.

[reppy007]

The way I understand it the blue goop that ya'll are referring to will not go thru a regular splice, if there has been a burnout in the cable and it has been spliced it has to be dug up and replaced with one of their splices that will allow the "stuff" to flow thru it, whether the "stuff" works or not who knows, but the positive side that I see to this procedure is just the fact that you are going to a transformer that is already really old and isolating the cables,#1 any numbering issues should be caught and corrected at this point,#2 the elbows on the cables have to be replaced to allow for the injection,#3 if the transformer is leaking or rusted out etc,etc, it can be replaced,#4 all of your other equipment ie" secondary pedestals, primary splice pits etc will be looked at while you are in the neighborhood and replaced if necessary, prior to this program getting started all we did was re-act to problems on a URD loop or radial, I consider this pro-active.

Im kind of wondering what the cost is,vs one spanning.

[bluestreak]

` For at last the past 20 years or so Conn. Loot & Plunder have been injecting the old unjacketed cable, It started out being done by a company out of New Jersey called Cable Cure, they had a good core group of linemen that came out of south jersey/ philadelphia area. We would switch out and grd. a section of cable they would put their radar on it locate any splices then they would blow nitrogen through the cable and if they got a flow we would energize the cable then they would start to inject the silicon based fluid pressurized at one end and a vacuum bottle at the other end then they would check it once a week until the vacuum bottle started to get the fluid, then stop the process and tag it . The problem is the MSD sheet says it's hazardous and flammable. When we started to ***** about training and PPE to work it they gave all that work to the contractors, evidently they really really cared about us but didn't give a **** about the contractors.

[reppy007]

` For at last the past 20 years or so Conn. Loot & Plunder have been injecting the old unjacketed cable, It started out being done by a company out of New Jersey called Cable Cure, they had a good core group of linemen that came out of south jersey/ philadelphia area. We would switch out and grd. a section of cable they would put their radar on it locate any splices then they would blow nitrogen through the cable and if they got a flow we would energize the cable then they would start to inject the silicon based fluid pressurized at one end and a vacuum bottle at the other end then they would check it once a week until the vacuum bottle started to get the fluid, then stop the process and tag it . The problem is the MSD sheet says it's hazardous and flammable. When we started to ***** about training and PPE to work it they gave all that work to the contractors, evidently they really really cared about us but didn't give a **** about the contractors.

This might be a stupid question,if so ..oh well but what exactly does that silicone based fluid susposed to do,,,,,,,,,,how does it help old cable......I have never been told .

[bluestreak]

After twenty years in the ground at 23 KV the insulation starts to break down due to electrical stress if you look at a cross section of the cable you can see what they call treeing which looks just like a tree root radiating from the conductor to the outside of the cable. The fluid flows along the conductor and fills the voids in the cable in effect restoring the cable to good as new, the problem is the cable may be restored but the shield wire/grd wire is still 20 to 40 years old and sometimes nonexistent. Another problem is the fluid isn't completely cured for a few months after injecting so if you have to work on the cable your have to deal with the stuff running out of the cable

[reppy007]

Good explaination Streak,I will be honest,there is some urd cable that,I dont have no idea how the you know what its still holding up,the jacket and all is disintegrated,even the concentric.....but its there in the ground still working.