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#149012 - 06/12/03 08:35 PM Fremont worker injured at substation
SAFTENG Offline
Member

Registered: 09/04/01
Posts: 142
Loc: Cincinnati, OH, USA
Fremont worker injured at substation
By Fremont Tribune Staff
A Fremont utility worker was injured in a Tuesday afternoon accident and is being treated at an Omaha hospital. Derril Marshall, general manager of the Fremont Department of Utilities, said the man was doing general maintenance at the substation at Somers Avenue and County Road T when the accident occurred. The man was working near high voltage lines on a metal structure at that station when it's believed one of his tools came in contact with the line, Marshall said. He was then transported to the University of Nebraska Medical Center in Omaha. The incident occurred around 1-1:30 p.m. Due to privacy laws, the name of the individual could not be released.

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#149013 - 06/12/03 09:07 PM Re: Fremont worker injured at substation
CaOperator Offline
Member

Registered: 04/17/03
Posts: 56
Loc: Los Angeles, CA, USA
As somebody who is required to write and execute clearances for this type of work, this type of accident is entirely preventable. We write clearances to either 'work near' or 'work on' equipment or lines. If his clearance (assuming he had one) was to work on the line (or even it's support structure) it should have been open and grounded. If his clearance was to work near the line he should not get close enough to touch it with anything, and should not have even had any tools long enough to reach the lines from his work position.

Based on what this article says either he exceeded his clearance or did not have the proper clearance for the type of work he was doing.

As the bumpersticker says - If its not grounded, its not dead.

BTW great site here, and Safteng is another great one too, very informative and interesting.

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#149014 - 06/14/03 01:18 AM Re: Fremont worker injured at substation
Trumpy Offline

Member

Registered: 07/05/02
Posts: 8540
Loc: SI,New Zealand
Ca Operator,
How does a Clearance work, where you come from?.
We quite often send these over VHF radio and it is repeated back and forth at least 3 times.
Thanks for joining ECN, mate!.
_________________________
Let's face it, these days if you're not young, you're old - Red Green grin

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#149015 - 06/14/03 09:53 AM Re: Fremont worker injured at substation
CaOperator Offline
Member

Registered: 04/17/03
Posts: 56
Loc: Los Angeles, CA, USA
You asked for it…Sorry if this gets long winded, but these things are quite important and detailed. It’s quite possible I may gloss over a step in here, but that does not make it any less important.

When someone needs a clearance, they first have to bring a request to the shift supervisor. The SS will make a determination if the clearance is even possible at that time (since maintenance does not always know what is planned, and operations needs to know the status of every piece of equipment).

If the SS determines that this is a viable request, then he will talk to the operator responsible for the area of the clearance. With simple clearances, a 480v pump for instance, the Operator and SS will discuss the steps for the clearance, and any extra precautions that may be necessary and issue a hold card with the pertinent data to be placed usually on the lock at the breaker.

If the clearance requires jacking out a 2.4Kv breaker, we always have a second person in attendance. These breakers are not out in the rack, but rather in high voltage rooms in the basement.

The operator and the person requesting the clearance then collect appropriate LOTO gear and perform the clearance. The key then given to the person who is performing the work, and the operator informs the SS the clearance is in place and makes note of it in the unit logbook.

If the job has anything to do with high voltage switching, a written clearance must be produced. The clearance will then lay out the specific order things are done and has spaces for the operator to log time/date/operator performing each step. The operator and SS will discuss the steps and if there is any concern over any steps, the operations supervisor will be consulted. Prior to a switching operation being done the dispatch center will also need to be notified, and agree with the clearance. Usually when you have to clear something in the rack it means that a substation normally fed by two sets of lines off of different busses will now be fed by one set, and therefore loads must be checked prior to switching to make sure the remaining lines have the necessary capacity to carry the whole load.

The clearance is then performed usually with two operators and the SS. The SS has the keys to the disconnects in the rack, and oversees the procedure. The second operator records the steps and times, and oversees the procedure as well. This helps to prevent somebody opening the wrong discos or failing to verify a CB is open prior to disconnecting it. It also helps to have extra eyes checking the discos to make sure all three knife switches opened/closed. We have lot of old equipment and they have been known to stick. LOTO procedures are followed here as well as you go along.

After the clearance has been performed (or sometimes during), the person who requested it is walked through the clearance and raises any concerns they may have. They will then sign the clearance and perform the work. The clearance is logged in the SS log, and the switchboard log. When they are through, they must sign the release and we go about restoring the equipment the same way (usually in reverse order of the written clearance).

I am not sure how the linemen work clearances out in the field, but substation clearances are always performed face to face rather than over the radio.

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#149016 - 06/14/03 09:10 PM Re: Fremont worker injured at substation
Trumpy Offline

Member

Registered: 07/05/02
Posts: 8540
Loc: SI,New Zealand
CaOperator,
Thanks for that explanation.
Very complete and informative.
Good to see that you have extra set of eyes during these Disconnections, with HV equipment.
These days, over here in NZ, with alot of our HV grid equipment, the disconnects are operated by UHF radio servo-systems, I don't trust these systems AT ALL!.
Out in the field, I have had incomplete disconnections, caused by one servo-motor not working, but there is no way that the Controlroom operator can know this, unless they are told.
I prefer mechanical Disconnects, for anything above 3.3kV, at least you have direct control over them and you can lock them out at your end!.
Radio control was supposed to make life easier for us Lineys, I have seen more single phases left live, since we got this technology, and at 11kV and 22kV, this is not good!!.
_________________________
Let's face it, these days if you're not young, you're old - Red Green grin

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#149017 - 06/22/03 12:38 AM Re: Fremont worker injured at substation
Trumpy Offline

Member

Registered: 07/05/02
Posts: 8540
Loc: SI,New Zealand
A sub-station, as I know them, have large amounts of Bare, Live metal.
Over here you have to have a seperate ticket that says that you are adequately trained and competent to work in these areas.
_________________________
Let's face it, these days if you're not young, you're old - Red Green grin

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