The focus of this article is the need for emerging technology to support the life extension of electrical power equipment into the future. I’m well-versed in most of the new testing techniques, but I think it’s important to determine the need. My world revolves around 480 V through 38-kV switchgear. I’m from the switchgear, rotating equipment, and transformer service side of the business, but today I’m talking about basic metal-clad switchgear 480 volts through 38-kV vacuum, oil, gas, whatever.
HISTORY
If you look at America’s installed electrical infrastructure of 480-V through 15-kV equipment, most of it was installed in the ‘70s and early ‘80s. It’s nice to think it’s all new and modern, but if you look through the big buildings in New York City, the wastewater plants, the universities, it’s populated primarily with older gear. As it ages, it must be properly maintained, updated, upgraded, or replaced..
Original equipment manufacturers (OEMs) originally thought the equipment would only last 25 years before being replaced with something new. The reality is that much equipment is now approaching 50 years old, with no sign of replacement technology in sight. Instead, every 25 years, we’re seeing an increasingly important use of life-extension technology to extend the service life of equipment. We need to start planning now to make this equipment last 100+ years. That sounds wild, but it is true.
When the major companies went out to the plants in the ‘70s and ‘80s and convinced the American industrial electrical users to replace their gear or to specify vacuum gear, particularly in the 5- to 15-kV range. The magic words were, “You won’t have to touch it, there’ll be no maintenance. It has sealed bearings and enclosed vacuum interrupters.” It is impervious to a lot of the things that killed older air breakers, so a service life of 20 to 25 years was placed on it, depending on who you talked to. The marketing department wanted planned obsolescence and something that wouldn’t be backward compatible, so that every 15, 20, or 30 years, you had to buy all new gear.
I’m from the engineering side. I would design something you could continually update and keep in service forever. So here we are today, some 50 to 60 years later, and we’re in a situation where there is no alien technology on the horizon that is going to replace the vacuum breaker, or the air breaker, or the oil breaker, or the gas breaker. Consequently, our job is to find a way to keep this equipment in service for 100+ years. As electrical power professionals, that is our charge!
PRIMARY OPERATIONAL CYCLE: ZERO TO 25 YEARS
Today, the operational maintenance cycle is about five years. When I first started in this business, we tested the equipment and maintained it every year, then every two years, then every three years, and now every five years. At some point about 20 years ago, we tried seven years, but that did not work out so well. If it’s not critical equipment, all the data indicates that five years is about as long as you want to go without cleaning, lubricating, adjusting, and putting human eyes on it.
Clean it, check lubrication, do an open-close exercise, and do some testing. That’s as far as many go with overcurrent protection devices. Some segments, like primary metals, sometimes choose to run to fail. Some don’t care what happens, it’s going to run to fail. If it fails, they’re going to fix it. They are going to throw a million resources at it and repair it overnight.
But we’re not going to talk about that guy. We’re going to talk about the rest of the industry that has some kind of maintenance program. When the gear comes from the ground as primary metals, it is developed and built, and it goes to the plant. If you must decide on possible replacement in the first 25 years of its life, it was most likely misapplied, or you have gone through big growth. By this time, it’s been tested four or five times, maybe more than that. The factory tested it. Acceptance testing probably came along behind it. It was energized and tested again. And then it was tested at every five-year interval. It’s been tested four or five times by the time you get through your first 25 years of operation. If you’ve done the primary current path work, you know the trip circuits work, and you have solid equipment.
If it’s in a clean environment, you’re in good shape. But if it’s a titanium pigment plant, a cement plant, a steel mill, a battery manufacturing facility, or if you’re close to the ocean, you must think about it entirely differently.
If it’s in a reasonably clean environment and you do a little switching in those five-year cycles, you see very few overloads, very few faults, and you never see a full-voltage bolted fault. No one ever really sees a full bolted fault. Very, very few of those occur. There’s usually some impedance involved. But you plan and build your system based on that possibility.
So, every five years, you see some maintenance. It could be one year. It could be six months; it could be four years. Five years is the longest I could recommend. Here’s why: Take your hands, put them together, and push as hard as you can. Hold it for five years. Then I’m going to ask you to pull your hands apart again as fast as you can. In five years, you are asking your circuit breaker to react and move as fast as you can today. Do you think you can? No, you can’t, and neither can your circuit breaker or protective device, so what you are asking is a very tough thing!
We ask a circuit breaker to do this with 1,200 pounds of force. Hold it motionless for four, five, six, seven, eight, nine, 10 years, and then react like Day 1. See a trip signal, react, drop a large latch, then a spring reacts, then the contact assembly parts, then travel accelerates, then hits a stop, then bounces, and then recovers. Then the fault is extinguished as fast as it did today after waiting many years with tremendous pressure on it, and in all environmental conditions! But we’re going to let you hold it perfectly for five years, and all your components are going to age. Your components are going to get hot, cold, hot, cold, hot, cold, and frozen. All kinds of things are going to take effect.
SECONDARY OPERATION CYCLE: 25–50 YEARS
So, after the first cycle of 25 years, when you’ve already tested the breaker seven or eight times, you must determine whether to replace it. Am I going to retrofit it? Am I going to do some repair work? Am I going to adjust, inspect, and lube it? Hopefully, you’re going to check the lubrication. Hopefully, you’re not going to spray some crap in there. You’re going to take it apart and lubricate it correctly. Then comes the next cycle. As you can see, now you’re on your way down the road. Now the equipment’s 50 years old. At this point, you’ve got some life extension decisions to make.
LIFE EXTENSION PRIMARY CYCLE 51–75 YEARS
After about 50 years, you’ve got to make some decisions on life extensions. Then it’s a third operational cycle at 75 years old. What are you going to do then? Now it’s been tested 50 times. Hopefully, it hasn’t been lubricated with the wrong lubricants, severely impeding the performance of the breaker. Maybe you’ve sent it out to a service shop, and they’ve done a lot of damage to the equipment, or maybe you have chosen your vendor well and your equipment has been properly maintained.
These things are resilient. We have done lots of extended-life testing on breakers and environmental chambers, and we try to slow them down. They are hard to slow down, but you can do it.
So, after 75 years, the equipment has been tested, tested, and tested. It’s time to make some decisions, and the decision is usually more major life extension or possibly replacement. This is the actual cycle we’re in today with equipment that has been in service for 50 and 75 years.
What are we going to replace? Let’s just say it’s difficult to replace the entire piece of switchgear. The cables are 75 years old. Try bending old lead-wrapped cables; it’s a disaster. It is very difficult because now there’s more equipment built around it. More changes are made at the plant that increase the available current. They’ve hung all kinds of different relaying and mitigation. They’ve done all sorts of things with the equipment. So you must be very careful in the decisions you suggest here.
You can always remanufacture the breakers. You can always add new vacuum interrupters. You can always upgrade the bus ratings, add stiffer insulation, install new instrument transformers, switches, relays, rewire it all, and hook it up. You can at least continue to maintain it, to upgrade the equipment in place to make it perform in a modern system. Or you can just replace it or fill the space with something similar.
Today, these are the kinds of decisions you must start making. This is a real opportunity for the people at this EPIC Conference and the people in this industry to replace the breakers, upgrade the bus ratings, and completely replace all the controls.
I see a lot of upgrades because everybody has bigger transformers in the system. The systems become stiffer suddenly, and you don’t have the proper ratings for interrupting. We see a lot of calls in the spring when equipment starts to be 50, 60, or 70 years old. It’s not as weather-tight as it used to be, so you have to continually reseal old outdoor gear with weather shields and all kinds of advanced coatings on the ceilings, plus a coating on the inside. If you don’t, you get condensation — dripping water. Arc-energy mitigation considerations are also involved with the rising interrupting rate you must have because the utility is stepping on you, or you added ties or bigger transformers, or whatever.
LIFE EXTENSION SECONDARY CYCLE 76–100 YEARS
At 75 years old, your five-year cycle starts over. You test again every five years, and over five cycles, now it’s 100 years old, although it might go more than 100 years. At this point, you’re going to be repairing and replacing it. You’re going to add some new technology. You’re going to have to find a way to integrate this old technology into whatever the new protocols are, which are going to be substantially different than today. Remember, there is nothing on the design board today that will replace the vacuum circuit breaker at 2,400–38,000 Vac.
NOW PEOPLE TALK ABOUT SOLID-STATE DEVICES, graphene, and all kinds of advanced materials, but getting to 50–80 kA or interrupting ability at full voltage is a tall task that will not be achieved before the gear is 100+ years old!
How are we going to keep this old gear in service for 100 years?
QUESTIONS & ANSWERS
Question: What can we do to make sure equipment will work for the next 10 to 15 years, and what technologies do we have at present that can extend life?
Ledbetter: I think you’re asking, “What can we do if we don’t have unlimited maintenance dollars? Where do you put your money? The first thing you must do is ensure you’re compliant from an energy-safety standpoint and from a system-coordination and short-circuit perspective. That starts with a firm understanding of your system parameters and what has changed since you last studied it.
You need to do a new study. Do you have a valid one-line diagram? Do you have a valid maintenance program? A lot of people come into systems, but they’re not the guy who built the plant or the guy who operated the plant through all the bugs. They’re the third, fourth, or fifth maintenance manager, and so many things have changed. Is your one-line diagram correct? Is your system coordination correct? Is the short-circuit study correct? Is your system compliant? Do you have proper tools and PPE in place? Do you have everything placed correctly? Once you have all that, then you can go to work on the hardware.
Then you must look at criticality. Which circuits are critical? You know which breakers are critical. Which other pieces of gear are critical? You treat the breaker that controls the primary coolant pump in a nuclear plant differently than you treat the breaker that runs the parking lot lights at a nuclear plant.
Once you’ve looked at criticality, a real key to switchgear is the circuit breaker. There are all kinds of systems where you talk about controls, instrument transformers, and decaying insulation. But if you talk about components, the heart is the moving device, the thing that has all the mechanisms, which is the circuit breaker. Start there to see if you’ve had problems. If you’ve had problems, what were the problems? Then you direct your maintenance dollars toward attacking those problems. Most breaker problems come back to lubrication unless it’s in a severe environment.
Once you’ve done the study work, once you’re sure your system is compliant, then it would be how to keep spiders, bugs, snakes, and moisture out of your switchgear. Extending the life of the gear is to make sure it’s in a healthy environment. It does no good to extend its life if it’s not in a healthy environment.
If the equipment is rated correctly, it’s been operating without problems, you’ve taken care of the lubrication, and it’s compliant with all the standards, you don’t have to worry about extending its life. It’s going to survive on its own. The ones you must worry about are the ones that are misapplied, such as a breaker or a piece of switchgear that’s in a repetitive-duty application. Or you’re opening and closing it to start a big motor. I would take that breaker out. I would go out and get the one off the parking-lot lights breaker that has 13 operations on it and exchange it with the one that has 4,200 operations on it. There are many simple, common-sense things you could do to extend the life of your switchgear.
Think about it before you spend a lot of money. The systems that have already lasted 30, 40, or 50 years are going to continue to last if they are properly maintained. Can you remotely monitor and control it? Is it easy to test? When you start looking at keeping equipment in service for 100 years, things must be done differently depending on the type of equipment. A lot of that has to do with a good condition-based maintenance program. Make sure you’re compliant, and make sure the equipment is properly applied. Make sure you have a good condition-based maintenance program. That alone will extend the switchgear for a long time.
Replace the breakers, clean the breakers. Take care of the insulation; do your testing, do some on-line monitoring, do some off-line testing, and do the things you can to determine the condition of your installation. We didn’t talk about timing tests, but that’s a good way to test to make sure your lubrication is doing its job. You just want to extend it a little bit more, because different pieces of equipment at your substation work in different ways.
We look at life extension in different ways. The circuit breaker side is for the electromechanical guy, and as an electrical engineer, I would always blame the mechanical guy. But when we look, for example, at transformer and bushing tests, you start life extension from Day Zero because of the data you receive from the manufacturer. You install the transformer and put it on the concrete base, and you start your commissioning procedures. If you have too much moisture inside that transformer, your life extension has been reduced from Day Zero. When we test, we do a dielectric assessment because there is organic material deep inside all the older transformers. But when you look down into the transformer, it’s organic chemistry. You have paper, and you have liquid insulation, possibly hydrocarbons. Like any other organic material, the tendency is to age and absorb available moisture, and the aging process is in one direction.
Teams are talking a lot about condition-based maintenance. I think you start with testing at least every five years. The panel slots are based on how we leverage technology, modernize the equipment, and use the data that’s available to drive increased reliability and uptime with smart condition-based maintenance. It initially goes back to the customer’s maintenance program. If you look at the electrical maintenance program that’s called out in NFPA 70 B, the real intention is to ensure that equipment operates properly. As you’re doing that maintenance, you continue to audit the routine to see if the maintenance is working. There are ways to offset some of that, such as sensors that allow customers to monitor humidity and temperature while the operator installs the equipment.
Modernization opportunities are out there. If you think of NFPA 70 B, any breaker over 250 amps needs a primary injection current test at least in acceptance or when you take over a new-to-you system. A lot of the older equipment doesn’t have that. If you’re a customer with a lot of older breakers, you’ll be able to utilize the electronic trip systems with a secondary test capability set to update those breakers. There are various modernization techniques and solutions to reduce overall operational expenses, and a lot of those also lead to increased safety.
Question: You mentioned that most circuit breaker failures are due to improper lubrication. We have a good, solid maintenance program, but what kind of education do you foresee will be required for workers to be qualified to do maintenance? How do we accomplish that?
Ledbetter: Lubrication is an issue because every manufacturer for every circuit breaker since World War II has recommended different lubrication, and 80% of them are no longer available. The truth is, if you can’t partially disassemble the breaker, you really can’t lubricate. So you’re in the field, and the maintenance department is saying, “Sunday at 6 pm, this plant’s coming back up.” You’ve got 300 breakers to look at, test, clean, adjust, and lubricate. What you don’t want is some guy out there blowing light penetrating oils on all the primary contacts, hitting all the mechanical points with light lubricating oil, and washing all the grease out. How do you get that message across? Dissimilar lubricants cause problems. They cause all kinds of chemical reactions that create heat and cause gunk that’s going to slow the breaker down. That doesn’t manifest itself for some time; it manifests itself over the years.
The breaker contacts are closed, waiting to react. The only way to get good data is to get first-trip data. There’s no other way to determine if your lube program is good or not because once you trip the breaker, you lose that first-trip data to extract the breaker from the cell. Then the next time you test it with a timer, it will be closer to spec than it would have been if you had captured the first-trip data. What it comes down to is that using just about any of the new modern lubes is better than mixing unknowns with different bases. You can’t make this system or any maintenance program idiot-proof. You can only make it idiot-resistant.
When you’re dealing with bigger high-voltage breakers, there is plenty of data. When you’re dealing with a 220-amp breaker, there’s no doubt about it. There’s no relay, there’s nothing. There’s still a set of overcurrent trips on it. I think the problem is with 480-volt, distribution-class, medium- and high-voltage breakers. There are ways to get first-trip data based on the trip device. If it has an electronic trip device, it has a sensor, but most breakers don’t.
CONCLUSION
Most of the time spent solving problems and working on new technology is not new technology. Applying old technology to new applications is a better way to put it. The first conference I ever went to was in Baltimore, and a Westinghouse engineer named Chris Bond got up and spoke about how, in the next year, they would have solid-state breakers that would replace everything, which you know we are still saying today — 45 years away. The only way we’re going to jump a quantum leap ahead of what we’re doing today is if an alien spaceship lands with unbelievable cold-fusion technology and magnetic drives in perfect condition with an operating manual. There have been no real breakthroughs in our power industry in the arc-interruption side of the business since WWII. I look forward to when that happens, but I don’t think I’ll be here.
Finley Ledbetter is CEO and Chief Scientist at Group CBS,a NETA Corporate Alliance Partner. Ledbetter worked in power engineering for 45 years. He previously founded Shermco Engineering Services Division, a division of Shermco Industries, a NETA Accredited Company. Ledbetter served as an applications engineer and instructor for the Multi-Amp Institute. He is a member of IEEE and a charter member and past president of the Professional Electrical Apparatus Recyclers League (PEARL).