The transcription of the video is below. 

Introduction & John Drummond’s background

Kerim: Hi, everyone. This is Kerim, Kerim Baran, with SolarAcademy. I have with me today, John Drummond, from Chint Power Systems. Welcome, John.

John: Thank you, Kerim. Nice to be here.

Kerim: Yes. Today, we are planning to talk about Chint’s higher voltage products and solutions, that’s specifically for the utility segment of the solar inverter space. 

And with that, maybe talk a little bit about your background, John. When I looked at your LinkedIn, I’ve noticed that you’ve been with Chint Power Systems for almost a decade here, mostly in the U.S. 

I remember the early days of Chint, and how you guys made such a strong entry in the C&I space, and now hearing about the utility segment focus and really learning more about Chint Power Systems as a company, has been enlightening for me. So it would be great if you can tell us a little bit about your background, and then maybe a little bit about Chint’s global footprint.

John: Yeah, sure. Sure. Yeah. Thank you again for having me. I’ve been with CPS America for just a little over 8 years now. And prior to that, I was with two other inverter manufacturers.

I kind of cut my teeth, so to speak, on renewable energy, in the mid-nineties, when I worked for a wind turbine manufacturer, and at the time that I was hired, they were doing what they referred to as non-wind projects. This was kind of a little pet project under the engineering director’s umbrella, and I reported to the electrical engineering department. That company ended up getting absorbed by two other manufacturers, eventually. And my roles with those companies started out that I was basically a lab technician, and then worked into a program management role. 

Eventually, I got involved in compliance testing and new product development, applications engineering, and so forth. And then I moved to Chint in the fall of 2015, when there was this kind of shift in the industry, to use string inverters, predominantly for C&I applications. 

But now we’re seeing them more and more being used in, as you mentioned, in utility scale applications. So string inverters to combat the historical premise that a central inverter was the way to go for utility scale projects. 

Chint Power Systems: A global behemoth serving the solar & electrical equipment market

Kerim: Yeah. So with that, can you tell us a little about Chint and how it started overseas and came into the U.S.? What are the various different things that they’re known for, maybe in their home country versus in the U.S. versus other markets? 

John: So Chint group is a global company. They are like the GE of Asia. I’ll call them something like that. They make just about everything under the sun, electrical. They make low-voltage electrical equipment, circuit breakers, contactors. They do building and automation. They do transmission and distribution equipment. I mean, they basically do everything. 

And they also have solar energy line of business. So they have CPS America, which is the company that we work for. And then there is a CPS, a Chint Power Systems, Asia. 

We manufacture two different products based on where these products are sold, the markets are sold into. So here in North America, it’s UL-listed string inverters that comply to all the standards that are required here in North America. And then, of course, the other products have IEC listings and Australian listings, and so forth, where they’re sold into those markets. 

Kerim: Got it. And there’s also a big, I think, billion-dollar plus transformer business along with all the inverters.  

John: Yeah, yeah. So Chint group is like a 14-billion-dollar corporation. And as I mentioned, we fall under their renewable energy business. So you may have heard of Astronergy PV modules. That’s a Chint group company. And then CPS – Chint Power Systems, America is a Chint group company. 

So we are fully, financially backed by this parent company. But we are somewhat of a separate entity in terms of the business here in North America. We’re based out of Richardson, Texas. That’s our legal office location just north of Dallas. And then we do have offices in California, where I work out of, and then also in New Jersey.

How have Chint’s products and solutions evolved based on the market dynamics?

Kerim: Got it. And my exposure and introduction to Chint happened when I used to work with CivicSolar, my prior company, as a distributor. I remember it as an inverter provider for the C&I space, but now based on our recent conversations, I’m aware that you guys are expanding beyond that, expanding into full solutions. Maybe you can tell us a little bit about why this transition is happening in your focus, and how things have evolved, as it relates to the products that Chint was selling in the U.S solar market? 

Yeah, let’s talk about those higher voltage products. And what’s driving the need for all of that?  

John: Yeah, so let’s start back. So the North American business was really started about 2012, and that was bringing transformerless string inverters to the market here in the U.S. This was a change that had already been adopted in areas like Europe, in Germany. So there was a code change in the National Electric Code here in the U.S. for what was referred to as ungrounded PV systems. So you no longer had to use inverters that had an isolation transformer to isolate the DC from the AC. And the PV array was no longer grounded. Typically, everything had to be grounded, either DC Positive or DC negative.

And with the advent of string inverters, we introduced that to the market. We had 14- and 20-kilowatt models. We’re kind of the first ones that were brought to the market really aimed at C&I, just a kind of early adoption of this type of product in these markets and those markets have essentially grown. And we developed other models. We now have a 25-kilowatt through a 60-kilowatt aimed at C&I. These are 1,000-volt DC products.

But the old 14 and 20 were only 600-volt DC models, but then, as the code cycle changes and the open circuit voltage that’s allowed to be used for PV systems evolved, then it became 1,000 volts. So there was a lot of people that were using these for commercial rooftop, big box stores, but also using these 1,000 volt inverters for what they referred to as small utility scale applications where they were grouping say, 30 or 40 inverters, and do a single step up transformer through a switchboard, and so forth. 

Innovating for the small-utility segment of the market. 1000V to 1500V solutions

And we started developing, and you know, Chint has always tried to stay on the forefront of innovation. We have things like separable wire boxes in our C&I products that are really advantageous for installation. If there ever was an RMA event, you know, you simply open up the disconnects, put on your lockout tag out, and then wait for the 5 minutes for any energy to discharge, remove what we call the power head, which is really the power conversion portion, but you don’t have to remove any cables or safeguard them, or you know any of that kind of stuff. 

So it really speeds up the process and a lot of our customers really like that. So we decided that we wanted to kind of get into the utility scale market a little more, and that was around the time when PV open circuit voltage went from 1,000 volts to 1,500 volts, and specific for ground mount, because the maximum voltage for buildings is now still at 1,000 volts.

But for a ground mount, or even a carport canopy which doesn’t qualify technically as a building, you can put 1,500 volts on it. So the advantage there is that you can play the old Watt’s Law. So as voltage increases for the same power level, your current’s going to go down, meaning your conductors can be sized less. Or if you just –

Kerim: Or you can save on the BOS.  

John: Yeah. Exactly, or if you keep the same current rating and go to a higher voltage and you get more power. So it’s kind of a win-win there. 

Chint’s 800V Solutions, its innovative design, components, and unique benefits

So we started developing 100 and 125 kilowatt inverters, at 1,500-volt DC. String inverters, again, these are still transformless designs. And I remember looking back, several years ago, when a 100-kilowatt inverter was a central inverter. 

And you think about the power density that’s all packed into this 100 and 125 kilowatt inverter it’s the size of a suitcase, you know, rather than an industrial refrigerator, or whatever it used to be. 

Yeah. So we did the same thing in terms of increasing the DC voltage, which was allowed by code by increasing the AC output voltage, or what the inverter interconnected with. So we went from 480 volts, 3-Phase to 600 volts, 3-phase – very common in Canada. 

There’s a lot of systems, a lot of older systems also here in the U.S. that still have 600 volt 347Y grid sources. So we did the same thing on the AC side by making an inverter that intertied at a higher voltage. That meant that the conductors would get smaller and so forth. And it’s a win-win. We incorporated those features like separable wire boxes into those products. So they were easy to install and easily adapted. 

So kind of moving on and keeping that same theme, we introduced our 275 kilowatt inverter, 1,500-volt DC, but it has an 800-volt intertie, 3-phase. Yeah. So again, a win-win there with keeping a small package size in terms of a string inverter. It weighs less than 200 pounds. It’s still the size of a suitcase. But you get all the benefits of the increased voltage, the benefits of string inverter, which I can go into a little more, as we talk about utility scale applications. But one of the kind of hurdles that our customers were getting was finding balance of system equipment that had these voltage ratings and were listed for this particular voltage rating.

Historically, you could get equipment that was listed as 600 volts, but it was like, you know, UL 508 or 408. I’m trying to think of the exact listing for the product. But it only went to 600 volts, and there was a disconnect between – the inverter has to work at an operating range of 110% to 88% of nominal voltage, right, which meant for a 600 volt nominal, you had to be able to operate at 660. Well, where do you get equipment that’s listed to 660 volts? 

So some manufacturers, some third party manufacturers were offering things like switchboards or multi-case circuit breakers that were dual listed to UL and IEC, and IEC went to 690 volts AC. But it was still a little bit difficult to come by. 

So what we’ve done at Chint Power Systems, America, is rather than just being an inverter manufacturer, we are now a solutions provider. So we have additional balance of system equipment that we can offer, one being what we call our switch box, which is a 3-in-1 combiner with a fuse disconnect. And then we also have what we call our breaker box, which includes multi-case circuit breakers, where you can combine up to 3 275-kilowatt in inverters into a single circuit.

The switchbox Version 1 and Version 2, so Version 2 is just a little bit different than Version 1 in that it’s turned 90 degrees. This was some customer feedback that we incorporated into the design, and I could probably pull up some pictures and show you the inside of the switchbox. So I will share my screen here and show you a little bit of the switchbox. 

So these are some pictures that we showed this product at RE+ in Las Vegas back in September, and this is a disconnect switch with 1,000 amp fuses and bus bars that will accommodate the conductors for combining the inverters into a single output circuit. This product was UL listed to 1741. I should say, listed to the UL 1741 standard with 3 275-kilowatt inverters.

And it went through all of the abnormal testing for short circuit, voltage spikes, every kind of abnormal that you would introduce with, when you’re doing product development, you’re going through certification testing, this product was evaluated to, and it was found that by testing the product with the inverters, so this kind of combined solution, that the response, the self-protection response of the inverters, essentially mimicked, having individual circuit protection for each inverter, and that it wasn’t needed. 

This was kind of an innovative feature that we came up with and tested and evaluated and got the certification for. So this product has been used for quite a few projects. There’s been a ribbon-cutting just about a month ago for a project in Montana that was a 105 megawatt DC that used the 275s and use this this DC switchbox arrangement.  

Offerings and Solutions Designed for Under 5-Megawatt Projects

However, there is a little bit of pushback, because when you look at these large utility scale projects, there is kind of a line in the sand that’s either over 5 megawatts or under 5 megawatts. 

And National Electric Code Article 690, defines a large PV system. They don’t call it utility scale. I think that’s just an industry slang. But they define that that line in the sand is at 5 megawatts. And anything that’s over 5 megawatts, under Article 690, is essentially an engineered design, stamped, and approved. However, some of the requirements are a little more lenient where you don’t have to follow all of the “Rules of the National Electric Code”, because it’s “Behind the –

Kerim: Because they’re bigger applications. 

John: They’re bigger applications. They are “Behind the fence.” There’s a lot of – 

Kerim: They’re out in the field somewhere, not on a building, next to people, all that. 

John: Exactly. Exactly. However, if it’s less than 5 megawatts like you’ll see, you know, projects that may be community solar at 2 megawatts or something like that, then you start getting scrutinized by AHJs, that say, “Hey, well, this doesn’t quite meet the code. You know, what about over current protection Article 240, you know, and so forth?” So we developed what we refer to as our breaker box, and let me pull up that picture – and I’m sorry. Let me find it first. And then I’ll share it with you. I apologize. 

Kerim: Right. Yeah. And this is for your less than 5 megawatt solutions, basically. 

John: Exactly. Exactly. So this does the same function. It is a 3-in-1 combiner. So it does the same function as the switchbox, and it includes 3 250-amp multi-case circuit breakers. These do have a 50,000 amp. interrupt capacity. And this meets the requirement for having individual circuit protection for each inverter circuit.

So at the bottom here, I don’t know if my mouse is showing up.

Kerim: Yeah. It is. 

John: But at the bottom of this enclosure, where you’re seeing the multi-case circuit breakers, that’s where the output of the inverters would attach to. And then the combined bus bars would be the output up to the step-up transformer the pad-mounted transformer, in this case. 

So this product is also UL 7041 listed. It’s a 3R enclosure. So you can see it’s got vents on either side of it. It does come with surge protection shown on the left side there. 

And this product would meet all of the requirements for the less than 5 megawatt applications. And I will share a document here as well. I’m hoping you’re seeing this slide deck. That’s a PDF showing some design options. 

Kerim: Yup. 

John: Yeah, okay. So this was a brochure that we handed out at RE+ that shows some applications for our 275-kilowatt inverters. 

And these diagrams are really for reference only, and we can work with your design team independently to work on the details. But what we’ve done, everything with a green leaf, are products that are available through CPS. These are the string inverter starting on the left. And I’ll zoom this in a little bit so your audience can see.

So this is a kind of utility scale application design option, where you’ve got 3 275-kilowatt inverters, 800-volt output that are combining with our AC breaker box that I just showed. And then you can use the fuse disconnect with a single input. You don’t have to use all 3. The bus bars are rated to carry full current. So this would be, you know, perfect for an application where you’ve got a disconnect requirement in a line of sight.  

Then another option is to just use a third party switchboard. It’s another option. Again, there’s no green leaf here, so this would be supplied by somebody else. 

And then for “behind the fence” option which I started the discussion with, where you’re just using the 3-in-1 switchbox we call it, which is the fuse disconnect, this is another option. So this, again, would be the “behind the fence” Article 690 design option. And then these solutions would be for utility scale and C&I, or when we say C&I it’s less than that 5 megawatt line in the sand.

Lead Times for Chint’s Balance of System Equipment

Kerim: John, I have a question about these various different designs that you just showed. In terms of when it comes to procurement for these various solutions, and considering that now we are in November 2023, what is the current lead times in terms of availability of parts? 

John: Yeah. Great question. Yeah. So you know part of the – when I mentioned the hurdle of acquiring 800-volt equipment and listed equipment was also just availability. You might be able to get it. But is it available now? Is it available in a year? Or so forth. So we have decided to manufacture these products, make them available. They are in stock. It’s a 4- to 6-week lead time for our balance of system equipment, and I mean the breaker box and the switchbox. We also offer skid-mounted transformer solutions. And those have 26 weeks lead time.

So not quite a year that you’re hearing from other transformer manufacturers. Sometimes you’re hearing more than a year. We can provide the transformer. It’s a 345 on the high side and 800- volt on the low side, secondary, in a 26-week lead time. These transformers are also available with different vector groups. So we have, essentially, a configuration sheet that you can fill out and decide, you know, which vector group you want. We also are starting to offer transformers that are in the 2.5 MVA size. The previous one that I mentioned is a 4.2 MVA. 

Kerim: If it’s okay, I feel like this is so key to the current energy transition. Because I was recently listening to an Elon Musk podcast. I think it was on Lex. And he was talking about how transformers – like it used to be the chips were the bottleneck a year ago or so. And now transformers are going to become the bottleneck because of all this increasing electrification and the electricity demand that comes with it. The bottlenecks are always as if they seem to be happening around the transformers. 

John: Yes, yes. 

Kerim: It’s great that you guys have that advantageous liftoff. 

John: Now, granted the design cycle for a utility scale project is much longer than a C&I application, right? C&I, you can do in a few months, get your permitting, and so forth. Typically, a utility scale project will take you know, years you know, if not, at least, 18 months or 12 months. 

But you know that through CPS America, you can get equipment quickly. So you know, if you start to break ground, you can at least do things, get things rolling ahead of time, in a much, much faster rollout than traditional. 

Kerim: Well, thank you very much for all this depth and wealth of information you shared with us

John: Yeah. Yeah.

Kerim: Anything else we want to cover in this call? 

Benefits of using String Inverters vs. Central Inverters in Utility Scale Solar Projects

John: Well, we had talked about the advantageous aspect of string inverters, and maybe kind of a string versus central argument. 

Kerim: Yeah. Right, right into it. Yeah.

John: Okay, so historically, you know, utility scale projects have used central inverters. When I say, a central inverter, I’m talking about a big skid-mounted, you know, requires a concrete pad to be installed on, oftentimes, huge equipment, a big flat bed. 

Kerim: Tied with the car. 

John: Yeah, a crane. Yeah, this big as a car, right? Exactly, if not bigger. And you know, that kind of seems like that’s just the way it’s always been done, right? 

Kerim: Right, right. I remember that was the case a decade ago, when we were – or maybe 12, 13, 14 years ago. 

John: And central inverters went from, you know, like I said, from many years ago, a big central inverter was a 250-kilowatt or half a megawatt, you know. Now they’re like 5 megawatts, and you know, a central inverter. 

And for some projects that might make sense. You know, you’ve got to have a nice level pad area. You’ve got to make sure your row spacing it. It can accommodate the vehicles and equipment to get in there with that kind of stuff.

But what if you don’t quite have that? What if you’ve got some complex terrain that’s not flat? It’s not square-shaped. You know, it’s not a big, perfect rectangle. You can use string inverters and string inverters can essentially be deployed everywhere that you have a DC combiner box, right, for your central application.

So you can distribute them out in the array and then your AC runs back to a central location. But what might happen is, you might have some AC losses in your conductors. And if you take this kind of central inverter topology of placing a central inverter near the pad-mounted transformer and running all the DC to it, you can do that same thing and mimic it with string inverters. I don’t know what manufacturer it was, but they coined the phrase “virtual central”, right, where they’re taking center – excuse me – string inverters and grouping them together to mimic the central inverter. 

And with that kind of design approach, you get what’s referred to as free DC voltage drop because you haven’t done your power conversion yet. Right? So you can upsize the array to a higher loading ratio, and then still, if there are any losses that that happens on the DC, before it gets to the inverter. And then you can convert it from DC to AC at that kind of central location.

However, also with string inverters, you’re going to get multiple MPPTs, right? So not just one inverter doing all the power conversion. You’re going to get a lot of individual, little workhorses that have multiple MPPTs, so you’re going to reduce your mismatch losses at the array.

So you’ve got a win there, and you’ve got perhaps, better system uptime. So if there’s a problem with an under-producing inverter or a complete failure, it’s going to be a fraction of the downtime, right?

And they’re easier to work on. You know, there’s no sophisticated spare parts in a string inverter. There’s essentially, what? DC fuses, maybe, and some fans or something like that. I mean, those are really the only consumables, maybe a surge arrestor.

Whereas, in a central inverter you’ve kind of got more sophisticated equipment inside. That also requires, you know, a guy in a space suit to come in and work on it. Maybe a really experienced, specialized engineer rather than, you know, some easy, low-cost labor to go in and swap out an inverter. And as I mentioned, it can be done in minutes rather than hours, in some cases – just the ease of handling a string inverter. Yeah.

So there are more trade-offs I can go into a little bit more. But I mean, that’s kind of one of them. 

Kerim: Great. Thank you. Thanks. Thanks for all this information again. I’m just thinking, maybe for a future series of conversations, what other topics can we schedule for feature – anything coming too?

John: What other topics? I mean, we can do a deeper dive on some design, you know, some of the features about our inverter. So we offer our 275-kilowatt inverter. Has 12 MPPTs. So we offer a 36-fused input version. So there are 3 fuses per MPPT channel. Or we offer a 24 input non-fused.

And the reason why we did that is that under Article 699, for overcurrent protection, if there are two strings or less, and provided that the conductor is sized to carry the current, you don’t need fusing and you can do away with over current protection. And that is really helpful, when you start using these new, large frame modules that are like in the 650-watt and above range that have these higher ISC ratings.

In some cases, you do the calcs, and it might say, you need a 35-amp fuse. Well, where are you going to get a 35-amp fuse holder, first of all, a holder that’s rated for that, let alone, put a fuse in it?

And there are some exceptions under 699, where for systems that are over 100 kilowatts you can do what they call a 3-hour peak average on your short circuit current. One of the options is to go to PV Watts and download the 87/60 data for your site. It’s a whole engineering process. But that might allow you to get to a smaller fuse. But you might also be stuck at something above 30 amps. So that’s another reason why we tried to be innovative and come up with products that were user-friendly.

Hey, I don’t need over current protection. I don’t need fuses for this particular application. I can use this version of the CPS string inverter. 

Kerim: Sounds great. Well, I’m sure there will be many more topics to talk about as the industry grows and the volts and the watts. And pretty much everything is growing on the solution sets.

And once again, John, thank you very much for sharing all this information. 

John: It’s my pleasure. Thank you, Kerim.

Kerim: I hope to see you in a future conversation. 

John: Sounds good.