Alan Ross

I’m Alan Ross, the managing editor of APC Media, and we are presenting a power panel. My guests today are from a diverse group of companies. We have got John Ulcar, who's the Director and Co-founder of Crosslink Technology. John will be sharing a little bit about himself. We have Jeff Door with us, who's the VP of R&D for the H-J Family of Companies, and Marco Tozzi, who is an old friend and has done this with us several times. He's a Senior Technical Advisor for Camlin Energy. Gentlemen, if you wouldn't mind, you're going to do a little bit about a quick intro about you and your company. John, go ahead and start for us.

John Ulcar 
Thanks Alan, I am the founder and owner of Crosslink Technology. We are a company that does formulating for the electrical-electronics industry. We supply products for the casting of dry type transformers, PTs, CTs, and various coils and windings, as well as cast our own electrical components, mainly transformer bushings.

AR

Jeff, tell us a little bit about your background in the company.

Jeff Door

I am Jeff Door, VP of R&D, the H-J Family of Companies. I have degrees in mechanical engineering and engineering management. I also participate in the IEEE Transformers, Switchgear, and Insulated Conductors Committees. I have been with the company for 22 years. I began as an engineering intern and had various roles in design engineering, design of components, machinery, and testing throughout my career.

AR

Marco, a little bit about yourself.

Marco Tozzi

Thank you, Alan. My background is electrical engineering, and my PhD was on partial discharges at the University of Bologna. I've been working for Camlin Energy for 12 years now, and recently we created a new department, Asset Performances, which I am the director of, focused on providing expert services on HV assets to our customers.

AR

Before we get into bushings or monitoring or a lot of the changes that are taking place within that part of the industry, let’s talk about the challenges and the changes that are going on in the power industry in general. What do you see? Because right now we have a demand for transformers that is far exceeding our supply. Everybody's trying to meet that demand. John, I know you are a student of the industry as well, so talk about your perspective of where we are.

JU

The Department of Energy is predicting a 260% growth in the next couple of years, just in the demand for power. But on top of that, with more building of high voltage transmission wires, there's going to be a requirement for more transformers, obviously, and more bushings. It's also estimated right now that about 35% of the current transformers are near the end of their useful life, and they're going to have to be replaced. But there is another thing that I'm not sure is totally obvious to a number of people, and that is because of environmental factors and weather events, such as more hurricanes, stronger storms, a number of utilities are going away from pole top transformers to padmount transformers, which, again, is just another stressor in terms of demand. Another thing I think could be a bottleneck is that the supply of steel for transformers is a real issue.

AR

The Transformer Manufacturers of America Association, TMAA, is an alliance partner of ours, and they are working mightily on that issue of steel for transformers. Jeff, your thoughts on the industry?

JD

As John said, we have unprecedented demand right now. We are as busy as ever. Challenges in supply chain have not impacted us too much but is something that we are closely watching. We maintain very good levels, having months of a lot of the inventory. We do a lot of porcelain assemblies, and anytime you're importing components like that, you must make sure you have a good, steady supply. For me, resilience is all about recovery. And as Ken mentioned, there are many aspects to that. To build a resilient grid, you need a significant amount of infrastructure and data and information, and to be able to do that, you need to have the ability to understand what it is that you're looking for and what these events are that are occurring. For instance, if it's an event like a tree that goes onto a power line, maybe a recloser trips or power comes back on automatically, that's an automatic situation that occurs. It's resilient. It's recovered on its own. So that's how I see it.

AR

Marco, your thoughts on the industry in general?

MT

Jeff and John are on the supply of components and bushings but I see the other side of the coin of what happens in the field, because we help to assess the condition of the bushings, and the condition of the transformers. And as you said Jeff, it's challenging because there is this crazy balance between being inexpensive, reliable and flexible. We see transformers with bushings in very bad conditions and you can't do anything because you don't have a spare bushing. Sometimes, to replace the bushing, you have to replace the GIS connection and to do that you must change the layout of the substation, so it is often better to change the entire transformer if old enough. Until you do that, you just pray that the bushing doesn't explode. We have phase shifters here between Italy, France, and the rest of Europe. No new transformer will easily fit the footprint where the transformer is. So there is a balance where you must push your asset beyond the end of its normal useful life and at the same time guarantee reliability high standards. So, you must maintain what you have and plan what you don't have because you need five years to get a new transformer, like in the US. I see this also in Europe, the transformer is ready to go, but the bushings or OLTC are not available because they come from another supply chain. A small component will get everything stuck. It is quite challenging.

AR

Thank you all. Jeff, one of the things we're seeing throughout the industry is a lot of technical advances. People are using this time to make technical advances and/or innovation within their scope. What is happening within the bushing supply chain that relates to innovation and technical advances?

JD

There are a few things. One is with some of the connector bushings. By IEEE standards they top out at 35KV, whereas in Europe they have higher voltages. We are having a discussion in the IEEE Insulated Conductors Committee on how to push that IEEE Standard higher. The market demands some of these components quicker than the standards can respond to them, so we are keeping up on that. Also with the increased transformer capacities, particularly in renewables, they are running transformers up to ratings and sometimes even over them. Things are running hotter and the components need to meet those demands. We see a lot of on and off, particularly with solar, go from 0% to 100% when the sun comes up. Not only do the bushings and other component materials need to handle this, but the bulk installation also needs to be able to handle it. Gaskets are also something you must consider, and not just from the temperatures we are seeing, but from compatibility with all the different fluids that are being used now.

AR

John, Crosslink is at the forefront of a lot of technology advances as a company. Share some of that.

JU 

We are looking at it from three points of view at this point. One is, as everybody knows, porcelain bushings, just by their nature, are very good at self-cleaning. They have great longevity in various environments. We are working on developing new epoxy formulations that have better improvement in terms of surface energy and water resistance and to give longer life in terms of not contaminating the surfaces. The other thing that we're working on, which I think is exciting, and I think Marco might appreciate, is that we are coming up with insulating materials that would be self-healing during a partial discharge event. So that would obviously prevent the deterioration of the insulating material. Again, if we can eliminate partial discharge at the initial event, it will prevent deterioration. And lastly, which is something everyone is thinking about nowadays is developing more ecofriendly epoxies that are not based on oil but on plant-based ingredients. That's a little bit more of a challenge that with time, I am sure we will develop as well.

AR

Many industrial and commercial utility customers, and the utilities themselves are making sustainability one of their corporate goals. That puts a requirement on the suppliers of transformers and other assets, which puts that requirement on you because everything you do for sustainability gives them credit, but before we go there, Marco, I want to go back technology and change. You can start with self-healing of partial discharge that John mentioned.

MT

There are three technologies available for bushings. One is oil impregnated paper, OIP. The other one is the resin impregnated paper, RIP, and the new one is the synthetic resin bushings, RIS. Give or take, 80% of bushings today in the field are OIP. RIP is growing and RIS, while not yet in the mainstream, they are coming. Every one of these different technologies is trying to solve some problem. For example, resin changes the game in terms of being eco-friendly, reduce the risk of explosions, for example. Synthetic ones, for example, replace the paper in order to have less aging due to moisture entering. For RIP bushings, one of the problems is partial discharge because that material will not withstand a partial discharge. And we have seen this by monitoring these bushings that sometimes you see the PD due to a cavity, and the cavity then evolves in a short circuit between the layers. We think the future is looking at synthetic materials, synthetic fibers, like in transformers using synthetic esters. Now, we are still dealing, of course, with the oil impregnated paper.

AR
John talk a little bit more about collaborating with customers, where your engineers are working with engineers, not just at the OEMs, but also with the utility company, correct?

JU

That's correct. They are trying to innovate as they are involved in dealing with tighter spaces. Dimensions are becoming much more important. Even the way we're connecting things, the components together are all becoming much more unique. Years ago, we were given a drawing by our customer who said, “Can you make this, yes or no?” There was no room for development. “Can you make it and what's your price?” Whereas now, customers are talking to us about developing products that can be maybe able to handle a higher electrical stress, a higher mechanical stress under certain conditions, and if we can make parts designed in such a way to meet those requirements and to fit within the spaces that they're limited by at this point.

AR
Jeff, talk about collaboration with your customers, and collaborating with their customers to bring about a new product, a new technology, or solve a problem.

JD
We have seen all the way from, as you said, a drawing, making it exactly like that, and we can do that. But those aren't the fun ones. We like to work with the customers where sometimes they just bring us an idea. They bring us constraints. We need constraints to be able to have somewhere to start. And we work alongside them, passing ideas back and forth. We have several experienced people in our engineering department where we do 3D modeling, we do simulations, electrical, mechanical. We do flow simulations for our epoxy moulding and casting as well, and then make tooling in-house, source all the components. And we have a high voltage test laboratory. We're able to do the testing for the customer. We've even had customers come in, witness their testing, and we're working alongside each other to make changes and to develop the product together.

AR
That is the future. Marco, I know at Camlin, you are working on many projects, but the same thing happens. Talk a little bit about your experience with collaboration.

MT
Yes, it has changed a lot in the last 10 years, I would say. It is now more about, “Can you really support your customer to find what the problem is, to find the solution?” Completely different. We now give a multi-year service to analyze the data, to understand the data, because otherwise, you just have monitors that don't give any information. With some customers, it is possible to proactively operate in a way that you can find the problem. For example, we published a paper years ago where we found a problem on one bushing. And thanks to that problem, finding what the problem was, opening the bushing, they could save a number of transformers and replace the full batch of bushings with a potential problem. From one bushing, you save maybe 20 transformers. And this was thanks to the asset manager, the subject matter expert of the company who wanted to find the problem. This is cooperation and collaboration. Also in the specification writing, we sometimes helped to write the specification of the transformer because the risk management starts there. Because as you say, if the specification is wrong at the beginning, it's already a problem in terms of risk management.

AR
John, do you have something to add?

JU
Yes. I would like to go back to comments that Marco and Jeff made, where Jeff said they have components six months supply ahead of time for their customers. And Marco said a lot of times, transformers are held up because bushings aren't being delivered. Going back several years ago, we were at the mercy of the purchasing agents. And they knew six months, nine months, a year down the road that these transformers were going to be built, but they ordered the bushings at the last minute. Obviously, it held up the production of a large transformer. I wouldn't say that we were educating the purchasing agents, but we were collaborating with them saying, “okay, you know ahead of time what you need. Give us a little bit more purchasing forecast.” And conversely, once we were able to determine their demand, we were able, obviously, to bring supplies in to meet those demands. In the past we might be handed a purchase order, take it or leave it. Now we are even collaborating with these same purchasing agents.

AR
Let’s talk about failure modes. What are the failure modes that we're seeing as it relates to bushings?

JD
Gaskets are an important common failure mode for bushings. It is something that I think we have handled very well in identifying good quality materials and identifying the right materials for the application. UV is a concern more for certain materials than others but shielding the gaskets from UV becomes important. Making sure they are suited to the temperature that they're going to be operating at and with some new materials, we must know where we're pushing insulation temperatures. You must do the same thing with the gaskets. There are materials available to increase those temperatures. Some come with a hefty price, others more reasonable. But you must select the one that can hit those high temperatures, but also not sacrifice on the low side as well. A lot of these transformers are stored in very cold temperatures before they are put into service. You can have those cold temperatures affect the gasket from the start, creating a loss of life before the transformer is even put into service.

AR
Marco, you've seen a lot of them. You mentioned the failure. You see the potential, like that one bushing you're talking about, that you could determine from that what the failure might be for the other bushings. Talk a little bit about from the high voltage side failure modes.

MT
On the high voltage side, the faults have a mechanical, thermal or dielectric nature. When they ultimately fail, they fail dielectrically. Apart from situations where you might have a bad connection on the top of the bushing, low oil, or worn gaskets, the internal failures typically are from two situations: one is the dielectric failure due to the short circuit between internal layers, the other is contamination of the insulation. The contamination can be, like in that case we mentioned before, from particles coming from external environment during the manufacturing process, or can be contamination due to moisture, which maybe is the most common failure mode for oil impregnated paper bushings. Moisture that enters from the gasket is very likely. Moisture enters, gets trapped in the paper, and then it migrates between the paper and oil, which means that sometimes you do the test, and the bushing is cold, and everything is fine. Then the bushing heats up during the summer season or because there is high load, the moisture gets out of the paper and the power factor changes, and you find the problem.

AR

John, your thoughts?

JU
To refer to some of the comments from Jeff and Marco, a common failure mode is due to thermal cycling. If you don't have the proper materials, with thermal cycling happening because of the various environments, whether you're far up north or near the equator. It could be any transformer during transport in use. It could be cycling from minus 40 degrees Celsius to 120 degrees Celsius several times. If the bushing cannot stand that amount of cycling it has to do with coefficient of thermal expansion, coefficient of thermal conductivity, then you can have cracking.

We have also found microcracks during installation. And in some cases, the installers aren't following proper protocol, putting, in some cases, induced stresses on the bushings.

You don't necessarily see those microcracks until they are installed and in use. Suddenly, you have electrical failures, unfortunately. One other problem we've seen in the field at times is that there could be leakage going between the interface of the conductor and the epoxy itself. Where you have leakage there could be aggressive contamination going back into the transformer, so the transformer becomes compromised.

AR
Let’s back to the collaboration part that we talked about earlier, and while this question is for all three of you, it is particularly for John and Jeff, as suppliers to the transformer market. What would you tell a young transformer design engineer some of the most critical things for them to consider when specifying bushings for transformers are? Let's start with you on that one, Jeff.

JD
Well, I feel like we've touched on some of these points already, but those would be the loading of the bushing and possible overloading, and what margins are being allowed depending on the type of bushing construction. With many of the resin types, they're not built for overloading. Some are, but you have to dig into it, see what material is used, what its capabilities are, and talk to the manufacturers. Same thing goes for gaskets. Even if the insulation itself can handle the overload conditions, even common industry standards allow for thermal short time currents. It can be 25 times operating current for a short duration, but it can also allow the bushing to reach temperatures where some damage, some loss of life of that gasket, can occur. So, gasket selection, whether it be for high temperature, low temperature, chemical compatibility, even UV, as you mentioned earlier, and ozone, are all very critical.

AR
Okay, John, any thoughts?

JU
For a young engineer, I would strongly recommend that they talk to people that have been in the field for a number of years, to get a feel for the theoretical and the practical. For instance, there is the theoretical amount of amperage that you can put through copper per square inch, and obviously, most transformer users are using them beyond their normal specifications or theoretical limit. They are overloading them. They're being used past their limits. And in most cases, they're doing quite well, so they were obviously overengineered for their use. If anything, I would tell a young engineer to really pay attention to people who have been around and listen to the practical part of it as well.

AR
Marco, what would you tell somebody who is designing a monitoring program for transformers, and they are asking you, what should I be looking for and at?

MT
You must ask the right questions at the beginning before starting to do the design. What Jeff was saying about overloading is very important. In the practical case, we do overload calculations for transformers.

Sometimes you might not consider, for example, bushings and tap changer in your calculations because you are doing the calculations for the transformer. So, you look around the windings, the maximum current in the windings and so on. And you might forget that if you apply that current, you might be exceeding the maximum current of the bushings. Bushings are important accessories of the transformer, very critical. In the specification and design stage, you must also consider the abnormal behavior around the transformer, let's say, in overloading and over voltages.

A recent theme is the fast-switching transients from GIS. This is something that is apparently causing some issues to some design of bushings, especially with resins. It is not like before, just designing the bushing based on voltage and current. You must also consider the environment where the transformer is s supposed to operate, from electrical phenomenon to pollution and corrosion and so on.

AR
I was at a conference and one of the speakers, one of the panelists, was from Southern Cal Edison. He mentioned the fact that because of all the increased transients from renewables, particularly from solar and wind, that it is exacerbating the failure rate transformers. They are aging faster because of all these renewables. The idea that a lot of renewables that come online create a system that ages; have you found that to be the case? Because is it aging bushings more rapidly? Jeff?

JD
can be, certainly. I know reverse flow in transformers is a concern. But one thing is with the harmonics from the inverters that has been an issue now being addressed. They are shielding the cores of the transformer to prevent the harmonics, through capacitive coupling, transferring through the core to the medium voltage side, where it was causing problems for bushings and connectors and cables, and the transformers themselves.

AR
John, have you heard anything about this? I call it super aging of an existing infrastructure.

JU
Like I mentioned before, we're just basically running the equipment hotter than it was intended for, and it is aging faster. Our customers, the OEMs, are developing transformers that are more robust, able to handle higher stresses. But again, that's still just meeting the current demand. We still haven't been able to catch up to the demand that is coming.

AR
Marco, any thoughts on this?

MT
I agree with what has been said. There is an impact. There are utilities that are taking countermeasures, for example, installing through-fault current monitors, devices that can understand what happens outside the transformer because their transformer was supposed to work in a certain way. Maybe they are facing 20 short circuits in the distribution grid or coming from other plants that are affecting the mechanical structure. Things are also changing to face this issue from renewables. Also, in the renewable plant itself, they have quite a challenge because they don't have the same technical knowledge of historical electrical utilities and are operating the transformer in an unknown environment without the same level of support the utilities typically have, because everything is seen mainly from the financial point of view. The transformer is just a node in the cash flow to a certain extent. They are facing a lot of challenges with the main step up interconnect to the grid.

AR
Last question gentlemen. Tell me a little about what your companies are doing today as it relates to serving the industry? Jeff, we will start with you and H-J Family of Companies?

JD
Well, we are busy, with a lot going on, a lot of growth. In terms of our manufacturing, our epoxy molding operation, we see tremendous growth. We have several materials, not as many as Crosslink, I can tell you that, but the materials we have developed here, our chemical engineering director formulates the resins in-house, and we run them through rigorous testing. We are optimizing our formulas for use in our process on our components with our equipment. That has worked very well for us.

Recently, for our APG process, we added a larger press than we have ever had before. The platen size is three times, so we're able to mold larger components right now. Our largest ever, several hundred pounds, multiple copper conductors encapsulated in epoxy.

As for the development of other products for power transformers, we have nitrogen blanketing systems for oil preservation and as I mentioned before, some new epoxy bushings for pole mount transformers. We are doing a lot of work with higher temperature epoxies for them to work with our bushings, low and medium voltage, to hit the 130C and 155C temperature ranges. We have a high voltage laboratory, where we're rigorously testing all of that.

We have hundreds of years in design experience combined. We have a lot of people who have worked in the industry for decades, working for us full-time and we have some who are now semi-retired and work for us as consultants. They are absolutely a great help to us.

AR
Thank you, Jeff. John, talk about Crosslink Technologies.

JU
I consider myself a techie. I love the technology part of it. So that is what I am going to talk about. We consider ourselves to be very innovative. Everything we do, we try to be customizable to the customer. We do projects that other people don't want to do, or think it takes too much time. We like to customize to the engineer's needs. Our philosophy is not to make our specific customer’s company successful, but to actually make the engineer look successful. He or she comes up with a need and we make the design. It becomes very successful. He becomes successful within his own company. And he looks good. The company looks good. They have a good product. That is where we're looking, even within that concept of innovation.

We're also doing that internally so that we can turn parts around faster. Again, lead times are always a big issue with customers. We're finding ways of lowering our lead times, keeping quality and delivery at 100 %.

It is really, in our case, very much a partnering thing. We obviously have electrical engineers. We have mechanical engineers on staff that are there to support our customers. We customize the designs and the processes to meet our customers' needs.

AR
Excellent. Thank you, John. Marco, you get to talk a little bit about Camlin Energy and that part of Camlin Energy is part of a bigger thing, Camlin Group, correct?

MT

Yes, correct. The Camlin Group has the Camlin Energy division, where we work with the utilities and operators in the energy sector. Our mission is really to establish trusted partnership with customers. And that's why we moved from selling the sensors like we did even 20 years ago into now the software and the services, because we see this need to assist the customer, especially industrial and renewable customers. Indeed, the combination of sensors, services and software is critically important for these smaller customers who really need this partnership, which is, by the way, a means to learn every day. It's a mutual learning.

This is the mission of Camlin Energy. We are really operating in this direction, to create this partnership. That is why in US now, we are expanding with facilities and offices in order to stay closer to customers . In Italy also we have now a big operation. So, depending on the market needs, we are expanding to stay close to the customer.

AR
The next generation is desperately going to be dependent upon exactly what each of you've talked about, collaboration, communication, educating them, because the next generation of engineer doesn’t want to make a mistake, as you said, John, you make the engineer look good, right? The idea that all three of your companies are customer-centric, which means they are people-centric, which means you are engineering-centric, which is the biggest transition that is taking place within the power industry right now is that we are teaching the next generation of engineers who specify, who manage, who monitor, and who make decisions about the grid, everything they need to know to make good decisions.

Thank you, gentlemen, for being part of that, for your time, energy and expertise.

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This article was originally published in the October 2024 issue of the Transformers Technology magazine, which you can access here.

To download the PDF version of this article, click here.