Find and Repair a 230kV 800Amp Oil-Filled Power Cable Fault

scattergood01Have you ever wondered what guys like I do, when we’re not telling you that you need to do some completely unaffordable thing to keep your house wiring safe? We’re telling the utilities the same thing.

I ran across this the other day, talking about fixing an underground cable from a powerplant in California. It also highlights one of the reasons why a fair number of us are not fond of underground, no matter how much prettier you think it makes the landscape. :)

How do you fix a shorted cable ? Not just any cable. An underground, 3-phase, 230kV, 800 amp per phase, 10 mile long one, carrying power from a power station to a distribution centre. It costs $13,000 per hour in downtime, counting 1989 money, and takes 8 months to fix. That’s almost $75 million. The Los Angeles Department of Water and Power did this fix about 26 years ago on the cable going from the Scattergood Steam Plant in El Segundo to a distribution center near Bundy and S.M. Blvd. [Jamie Zawinski] posted details on his blog in 2002. [Jamie] a.k.a [jwz] may be familiar to many as one of the founders of Netscape and Mozilla.

To begin with, you need Liquid Nitrogen. Lots of it. As in truckloads. The cable is 16 inch diameter co-axial, filled with 100,000 gallons of oil dielectric pressurised to 200 psi. You can’t drain out all the oil for lots of very good reasons – time and cost being on top of the list. That’s where the LN2 comes in. They dig holes on both sides (20-30 feet each way) of the fault, wrap the pipe with giant blankets filled with all kind of tubes and wires, feed LN2through the tubes, and *freeze* the oil. With the frozen oil acting as a plug, the faulty section is cut open, drained, the bad stuff removed, replaced, welded back together, topped off, and the plugs are thawed. To make sure the frozen plugs don’t blow out, the oil pressure is reduced to 80 psi during the repair process. They can’t lower it any further, again due to several compelling reasons. The cable was laid in 1972 and was designed to have a MTBF of 60 years.

Finding out the location of the fault itself was quite a feat. It involved time-domain reflectometry (inconclusive), ultrasound, and radar (didn’t work) and then using an Impulse Generator-Tester (Thumper) which got them pretty close to the defective segment. What pinpointed the problem was a bunch of car batteries and some millivoltmeters. They hooked up car batteries to both ends, tapped the cable at several points and knowing the drops and resistance of the cable, got within a few feet of the fault. Finally, X-Ray equipment was brought in. Sure enough, they could see the cable shorting against the steel wall of the pipe. Cutting open, and closing it all up, required certified welders spending up to 8 hours on each section to avoid damage to the paper insulation. The welders placed their thumbs 3 inches away from the seams they were welding, and stopped when it got warm to touch, allowing it to cool off before starting again.

The failure was attributed to “TMB”, short for Thermal Mechanical Bending. TMB causes the cable to wiggle in place due to load surges. This eventually causes insulation failure due to abrasion against the pipe and separation of the many layers of paper tape. They repaired the short, put aluminum collars in most of the joints to hold the splices in place, and have added a load management scheme to reduce the current peaks. Apparently, the fix wasn’t good enough. According to this Wikipedia article, “the 315 megawatt capacity Scattergood Steam Plant (Unit 3) to West Los Angeles (Receiving Station K) 230 kV line is having to be replaced after only 45 years of operations, due to multiple failures within this rather long single-circuit, oil-filled, “pipe type” cable.”

Find and Repair a 230kV 800Amp Oil-Filled Power Cable Feels Like Mission Impossible | Hackaday.

TDR’s are one of the most useful diagnostic tools ever, they pay for themselves quite quickly but it’s nearly impossible to convince bean counters that think Radio Shack sells useful meters that a $2K plus tool, that doesn’t fix anything, and occasionally isn’t good enough is justified. Heck, I haven’t even quite convinced myself yet. Thumpers work (sometimes) on the principle of “letting all the smoke out”. It’s much easier to find a broken something than a cracked one, after all. For the rest, if you’re interested follow the links.

It’s part of the reason than the electrical trades are often so fascinating to be in.

And there’s this, from his comment stream, showing how sometimes we manage to get authorized to buy a new widget.

Having solved all other problems, Obama to fix your dishwasher

Seal of the United States Department of Energy.

Seal of the United States Department of Energy. (Photo credit: Wikipedia)

Well, guys, Apparently, our appliances still aren’t efficient enough. Of, course you know, and so do I that every time the government mandates things for your own good, the aforesaid things get worse. How many times do you flush your new super efficient toilet? Yep, so do we all. How many time do we have to flush a low flow toilet before it uses more water than the old one? 2 maybe 3.

You know of course that washers and dryers made in the 60s and 70s will last forever, you probably also know that new ones won’t, a couple of years is it. Why? because they are efficient. Sounds counterintuitive, but really, it’s not. You make things efficient by making them just barely good enough. Very little margin involved, just enough water on average, just enough motor, don’t use 16 gauge metal when 22 gauge will work, and so on. You make long term dependability by over engineering things- making them better than they absolutely have to be. You can’t have both, and you can’t choose anymore either.

From Hot Air

I guess he really was multitasking out on the golf course. The President’s team has been hard at work behind the scenes, coming up with a strategy … well, maybe we should say plan, to address the nation’s many challenges.

Spurred by President Obama’s climate action plan, the Department of Energy is pumping out new standards for refrigerators, dishwashers, air conditioners, ceiling fans, furnaces, boilers, water heaters, lamps and many more appliances.

The administration says the standards will not only help the planet but also stimulate the economy by saving consumers money on their energy bills that they can spend elsewhere.

After what we’ve been through with energy regulations, you’d think the administration would be at least a little hesitant to leap in for another grab at that brass ring. I mean, won’t a sudden raft of new requirements for the products everyone has to purchase have some, er… unintended consequences? William Teach seems to have been thinking along the same lines.

While the rules may save a bit of energy (and there is nothing wrong with that, though it should be the consumer choice, not Government Mandate), it will also drive up the cost of the appliances/devices, which will harm the lower and middle classes.

Having solved all other problems, Obama to fix your dishwasher « Hot Air.

Dodging Bullets

While dodging bullets is not a recommended practice, it is considered far superior to not dodging bullets. What is he talking about?, I hear. This, apparently we got lucky last month, and missed getting hit by a good sized Coronal Mass Ejection (CME). NASA seems to think that if it had happened a week earlier, it would have made a direct hit. Could be, it has before.

Back in 1859, there was the Carrington Event, a series of powerful CMEs that were powerful enough to set off telegraph instruments all over the world, even causing them to spark and set some telegraph offices on fire. It also caused the Northern Lights as far south as Tahiti. Now the thing is, in 1859 the telegraph was about as high tech as it got, and electric/electronics technology is the most susceptible to plasma events; steam locomotives don’t care, computer controlled diesel -electric ones do.

And that’s why it matters now. In 1859 we could afford to rebuild an occasional telegraph office. Now our entire world is tied up in it. Let’s think about this a bit. The backbone of the internet may, repeat may, be somewhat resistant, given that it is fiber optic, but most of us have metallic links, either telephonic, or cable to that backbone. Satellites depend, the plasma may take them apart, (I can see a couple of ways, but don’ know enough in the field).

But the biggie here is the power grid. If you are old enough, you may remember the New York Blackout in 1965. Here is a bit from Wikipedia about it

The cause of the failure was human error that happened days before the blackout. Maintenance personnel incorrectly set a protective relay on one of the transmission lines between the Niagara generating station Sir Adam Beck Station No. 2 in Queenston, Ontario. The safety relay, which was to trip if the current exceeded the capacity of the transmission line, was set too low.

As was common on a cold November evening, power for heating, lighting and cooking was pushing the electrical system to near its peak capacity. Transmission lines heading into Southern Ontario were heavily loaded. At 5:16 p.m. Eastern Time a small surge of power coming from the Robert Moses generating plant in Lewiston, New York caused the improperly set relay to trip at far below the line’s rated capacity, disabling a main power line heading into Southern Ontario. Instantly, the power that was flowing on the tripped line transferred to the other lines, causing them to become overloaded. Their protective relays, which are designed to protect the line from overload, tripped, isolating Beck Station from all of Southern Ontario.

With no place else to go, the excess power from Beck Station then switched direction and headed east over the interconnected lines into New York State, overloading them as well and isolating the power generated in the Niagara region from the rest of the interconnected grid. The Beck generators, with no outlet for their power, were automatically shut down to prevent damage. The Robert Moses Niagara Power Plant continued to generate power, which supplied Niagara Mohawk Power Corporation customers in the metropolitan areas

But the thing is the grid in 1965 was a mechanical beast, it could cascade tripping out like it did, but men had to go around and reset many of those devices, find enough power to flash generators and sundry other tasks, that’s why it took as long as it did to get everybody back on. […]

But now, we have the super-duper computerized grid, that we can control all those protective devices from our power control centers. It is an incredible accomplishment, but nothing is perfect. I suspect that a plasma event will set up surges in these lines that will trip out overload devices, over much more territory than the northeast, because we are much more connected now. If that’s all it does, it’ll take a bit but our power will be back in a few hours or days, no big deal.

But power lines collect stray energy like nothing else, men have been killed by a lightning strike on a line a hundred miles away. What happens if that plasma event get into electronics that control the grid, or for that matter the office you work at, your house, our world really. What then? All those computers installed in your appliances are built in computer controlled factories. The food you eat comes to you on railroads and in trucks. Both are controlled by computers. So are our cars. they are all more, or less liable to damage from a surge. And a CME is the great grand-father of surges.

How long do you think it will to replace all this stuff to the level of say 1980? I’d say it will be measured in years, not months. I would also say that if you are not prepared both mentally and at least to some extent physically, you likely will not see it.

You know, we have talked about EMP attacks occasionally, this is an EMP attack on the entire world.

Or not. No one really knows.

Decisions: Good and Bad

English: Ameren lineman practicing a rescue.

English: American lineman practicing a rescue. (Photo credit: Wikipedia)

Right and wrong. Often we think of them as the two sides of a coin as it were, and often they are, but are they always? Let’s dig a little deeper here.

As a power lineman, and as an electrician I often deal with power that is concentrated enough to kill you quick. Not that it’s always in the line of duty.

Many years ago, a woman friend of mine had a TV fall into the bathtub with her child. The child was killed. It was called a horrible accident, and it was. Or was it? She knew, or should have known that you don’t let electrical appliances get anywhere near the bath, yes some, such as hairdryers are less dangerous because of safety regulations but still, you are taking a risk. And a CRT television (which was the only kind then) is very high on the list, risk wise. There are very high voltages and some are stored for a time. Bad news. She lost the bet. Sadly, although nothing could replace that child, neither could she have another. And so a woman who by most measures was a pretty good mother, is now childless. But it really is her fault, because of her carelessness. But I did and do feel sorry for her as well as the child.

Another story which I’ve told before

They were lucky but, every time Chris looks at his buddy, he’s reminded. Just as that woman in the first story is every time she sees a small child. We say it so often but do we believe it Actions have consequences. Believe it, they do.

And as a responsible supervisor, it is entirely my responsibility to make sure my crew is safe, from hazards known and unknown. Acts of omission can be (and often are) just as bad as acts of commission

I’m very glad neither of those accidents are on my conscience, I’ve been in a measure lucky but I was also taught to be careful, and what can happen when you are not. And yes, I do have some scars from near misses, both physical and mental. We do our best, that’s all we can do.

Church-of-EnglandWhat started me thinking about this now was that yesterday, my co-author Jessica’s fiancé was ordained a priest in the Church of England. And yes, I am extremely happy for them, and even more for the congregations that will have their services over their lifetimes. But what made me think about those stories above is this.

A few months ago, a young woman came to his rectory because she had heard she didn’t need an appointment to talk to a curate. She was in trouble, she was single, and she was pregnant and she didn’t want to be. But let us let Jess tell the story herself, because she was there and she shared with us then. Please do read it, it is here.

It is a remarkable story isn’t it? Especially the part about how she knew she had done wrong, what we would call grievous sin, although that term had no meaning to her.

And that is something that Jess and I have talked about with each other. In the United States, nearly everybody has some passing familiarity with Christianity, it may be entirely wrong, and yet, as a rule people, while they may think us judgemental (and sometimes we are) and with our noses in other people’s business (ditto), they have an idea of what we believe. In Britain, I gather that is not nearly as true. It is entirely possible to grow up and live your life without ever once coming in contact with Christianity. How that interacts with having a state church, I have no idea but, in any case it’s sad.

Most of you know that I consider abortion to be nothing less than infanticide, a fancy name for murdering your child, and I do.

But here’s the thing. In my examples above the actors knew what they were doing, they made an informed choice. In the case of Jess’ friend, she really didn’t. [As an aside here, she has become a stalwart member of the congregation, helping to run a homeless shelter, and very happy in her new-found faith, or so Jess tells me. I admire her greatly, and pray for her often.] But in Britain as in America, for a large part of the population, abortion is a convenience, used to avoid problems in your career and in your love life. In truth that was the case here.

But here, God in some hidden recess of her told her that she had sinned, and from what Jess said, I would guess that she was close to the point of adding suicide to her list of sins. I don’t know if you have ever been close to that black place of despair, I have, a couple of times, and one does not come back without help, of a friend, of a counsellor, or a pastor, and /or God himself. But if you do, you tend to come back stronger.

And that, my friends, is why I don’t condemn people. I do not know what they know, nor do I know how they reached their decision. This young woman reached out to those who were supposed to help her, and they were too busy, but she persisted and found a willing ear in a CofE curate. he listened and sympathised, as was right because he couldn’t make the decision for her. He moved her enough for her to want to see him after her abortion, and in that meeting, the three of them, plus God himself, saved that woman’s life. But reminding her that while those of us that are guilty (and that is all of us) must not cast the first stone, Jess’ friend as well as the woman at the well was instructed (as are we) “Go and sin no more“.

And the way I remember that is to always remember that one can only make decisions based on the knowledge that one has, if we have more complete knowledge, and they ask us, we must share our knowledge (and belief) but we may not, and even God does not, force them to use our knowledge. We all answer individually.

ABC= Always Be Careful

High-voltage lines for the long distance trans...

High-voltage lines for the long distance transportation of electrical energy (Photo credit: Wikipedia)

It’s that time of year again out here, we’re well into harvest, and everybody concerned is going full-out trying to keep up. That means nearly everyone is working till they get stupid. That’s the term I use when you keep going until you’re so tired that you’re not thinking clearly anymore. It tends to be endemic this time of year around farms, and with those of us that work in the industry.

I don’t condone ignoring safety rules but, I recognize it’s going to happen sometimes, and yes, I’ve done it too. But the thing is, I’ve been doing this work for nearly 50 years, and have pretty much of an instinctive knowledge of what can happen. I also know that some rules are not to be broken ever. If you think you know which, you don’t, so don’t break any of them.

By the way, I find that the older I get, the fewer I break, and then only for very good reasons, and not shutting down your operation is not one of them. About the only reason to for me anymore is to rescue somebody, and that I have to think about. Because it’s not going to help them if I kill myself trying to rescue them, is it? And with electricity it is quite easy to kill yourself.

In this first video, although it’s filmed on an industrial panel, it’s at a level that is available in your panel in your house. I know a lot of you like to do your own work. In truth, I’m sympathetic but, if you don’t know what you’re doing without guesswork, call a professional

Trust me, I’ve seen it in real life and you don’t want to! Luckily it was on a small irrigation pump but it was bad.

Look Up for Safety’s Sake

If your working with portable grain handling equipment, or even harvesting equipment sometimes, you can get much too close to overhead power lines. the only real solution is to pay attention This video is of a twig falling across the most common distribution voltage in the United States

You do not want your auger playing twig in this scenario. Along with that and besides winter is coming with ice storms and such, what should you do if a power line falls on your vehicle? Don’t know? Here’s a video that will show you. Watch it all, it’s important.

Remember that because it could quite easily save your life.

In fact, if you see any kind of wire laying on the ground, stay away from it, and keep others away and call the power company or 911 If you’re around industry or even a fair number of systems on the farm, you know that a lot of electricity is used at what we call 480V. It’s the most efficient overall voltage for commercial and industrial use. But it also can be a very dangerous voltage. Here’s another video

I saw a similar video years ago where the cover of the panel was blown clean across the room. There is an incredible amount of potential energy there. This is a demonstration by Progress Power of some of the things that can happen around power lines

Those of us in the industry have spent thousands of dollars on tools and education about these hazards and our rules change nearly every year as we learn more. If your interested, this video talks about some of the research that is being done

But, in truth, what makes a safe job, is safe workers. I can provide you with enough Personal Protective Equipment (PPE) to make you unable to walk across the room. But if you are overtired, impaired, or just plain careless, it doesn’t matter. Sooner or later, this is going to happen, and I or somebody like me is going to have to explain to your loved ones why you will never be coming home again.

So whether you’re a practicing professional or simply a consumer always

Be Careful Out There.

ps. You may have noticed that I never mentioned OSHA in this article. There’s a reason for that. I find some of their rules and paperwork requirements as nonsensical and burdensome as any of you. And if you read here often, you know how much I resent intrusive government. But, in today’s world, if you are a practicing electrician or lineman, OSHA is your friend. Far too many companies can not see beyond the monthly bottom line, and in a production environment, they will push you to violate every rule and procedure and even your common sense. Without OSHA you have very little protection from them. It’s definitely imperfect protection with our corrupt government but it’s the best we’ve got for now. In the last analysis your safety and that of your crew is, as it always has been, your responsibility. Nobody else’s.

A Snake in the Stubble

center+pivot

A center pivot system

Back in the day, I spent some years as a pivot tech. It was pretty interesting, there’s more technology in there than I would have guessed. It’s also a good way to get your exercise when you consider that the average machine is a quarter-mile long.  The dealer I worked for sold between 50 and 100 machines each year and they all had to be installed along with whatever options the customer had bought. That can range from a pressure switch to being able to control the entire machine from his iPhone, so it did have its moments.

But a lot of the time it was merely the pressure to get them hooked up. We rarely built the machines, contractors did, there just wasn’t time. We usually built one or two a year just to keep our hand in, but between wiring, and repairs, and even grain handling equipment we usually had other ways to spend our time.

We had one year where whoever the contractor had doing wiring, had a habit of nicking the wires at the motor. These machine use a specific style of cable, which has a corrugated metal shield, to help protect from lightning, and they are rather difficult to strip. And if you were careless, you would nick the insulation on the individual wires, most likely you wouldn’t notice it either. And he didn’t. And when we went over these machines at first start, before we turned them over to the customer, we didn’t either.

Valley-Irrigation-visual

A center pivot control panel

But eventually, a nicked wire will burn off, stopping the motor. And, of course, it has to do with starting and stopping as well as running time. So the motor the furthest out, which works harder burned off first. Yay! By the time this started it was the middle of July, the corn was head high, and it was 90°+ and usually the pivot had been running so the local humidity (and mud) were plenty high. It’s an easy fix, usually though, restrip and reconnect the wire, although occasionally you’ll have to replace a motor. The hard part is walking anywhere up to half mile through the cornfield to do so. Fun days. So the next year we decided to wire our own machines.

Which was fine, of course it was, I was one of the people who pushed for that decision. But that also meant quite a lot of work for us to do. At every tower there are 30 wires to be connected plus odds and end, and some other stuff at the pivot point. When you’re rolling along, it takes about 15 minutes per tower, and with me it was mostly helper work, while I did the ends of the underground, panel options, and pivot point. When I had a helper, of course, which wasn’t always.

Anyway, one day we were doing this, on the way into the field, I had dropped my helper at the end tower, and he was working his way in, while I worked the pivot point, this one had a generator so it was somewhat quicker to wire, and I was doing the collector ring, which is that dome-shaped device on top, which allows the machine to go around in continuous circles, without tearing out its wiring.

I’m moving along when I hear this excited shout. I look around, and my helper is about four spans out, and dancing like a crazy man. So I get down to the ground and in my pickup, turn around and go bouncing down there, as fast as I can. That means about 30 miles an hour across a ridge tilled field. In a ridge tilled field, the ridges are anywhere from 18 to 24 inches high and 30 inches apart. It’s not a comfortable ride, slowly, let alone at 30 miles an hour, even with a pickup that weighs something over 9000 pounds.

A ridge tilled field

A ridge tilled field

Of course, I figure he’s managed to hurt himself, although the way he was dancing around, I was pretty sure he hadn’t fallen off the tower, which is the easiest way to get hurt. But, he hadn’t. When I slide to a stop, he runs around the back of the truck and grabs a shovel. He then proceeds to very energetically hack at the ground. By the time I get out, he’s pulverized about 3 square feet, and running out of breath. So I ask him what all the excitement is, cause I haven’t a clue.

He tells me that he finished wiring the tower box, and was coming down to do the motor, when he jumped off the base beam, (that’s the horizontal tube that holds the tower and the wheels). It’s a fair jump, many machines, like this one have 38″ tires, which puts that beam at about mid-thigh. When he hits the ground, something by his foot got his attention. Yeah I would say it did, it takes a fair amount of volume to attract the attention of someone doing something about 1100 feet away, even in a quiet field. But, he managed to make me think something was seriously wrong at that distance.

So, I clamped one hand on the steering wheel, and one on the cab roof to try to keep from getting a concussion as I flew across the field, so that I could watch him turn a 30 inch or so rattlesnake, into hamburger.

He had landed about three inches from its head, and what attracted his attention was its irritated rattling. But it paid for its irritation with progress…

with its life

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