[00:00:00] Speaker A: Hello and welcome to the Consulting Specifying Engineer podcast. I'm your host, Amara Roskas, and I've connected with two of Yaskawa's experts, Don Cameron and Jordan Engel. We'll be talking about power quality. Thanks for joining me today, gentlemen.
[00:00:17] Speaker B: Hello.
[00:00:18] Speaker C: Good afternoon.
[00:00:19] Speaker A: Excellent. A little background. First, about our two experts.
Don Cameron started his 28th year in the motors and drives business in 2023.
In 2005, he began working in the H VAC VFD business and has remained there ever since.
His expertise encompasses everything from the challenges associated with drive startup, the nuances of getting specified, and driving product development to ensure continued success in a very competitive space.
Jordan Engel has been in the motors and drives business for more than 20 years.
In 2023, he transitioned into a product management role at the factory and will be relocating his family from New Hampshire to Wisconsin.
Jordan's field experience brings an extensive background of variable frequency drive applications.
All right, I gotta ask Don kind of a basic question here, but why should engineers be concerned about power quality?
[00:01:24] Speaker C: That's a great question. So, you know, utility companies who provide the power for the world, they're the ones really driving the whole the picture of, you know, what is power quality?
And it impacts them because the voltage distortion that their customers put back on the grid ultimately determine if they have to spend more money on expanding and make more infrastructure investment.
Customers, the owners of building that engineers serve, they care because it can impact the equipment in their building.
So really, engineers need to work to make sure that both their customers are happy and they can make the utility company happy.
So since the mid-1990s, we have witnessed Guide Specifications for Projects, or VFDs, implementing various stages of IEEE 519.
The VFD community at large has developed solutions achieving various levels of compliance with a de facto standard ending in a commercially available solution that says you must have 5% CHDI drive terminal.
While a very safe selection to ensure compliance, in reality, this is a huge waste of resources and ignores the actual intent of IEEE519.
The primary transformer available short circuit current rating versus the maximum demand load current should be driving the building's equipment schedule.
The latest iteration of IEEE519 was released in 2022 and really is a huge step forward in emphasizing the point of common coupling as the point of measurement.
[00:03:04] Speaker A: Okay, so another kind of basic question for you, Jordan. What exactly is harmonics and why is it important to align electrical engineers?
[00:03:14] Speaker B: Well, thanks, Amara. Yeah.
Harmonics are line currents that result upstream of the device on. On the. The Network. In this case, we're talking about variable frequency drives. They result from non linear loads. And in my work previously, I would do lunch and learns for consulting engineers. And I found that there was a very wide range of understanding on this subject. So this is a good question to cover. But harmonic currents constitute a form of reactive power. These currents do not ultimately contribute to power being delivered to your load to do some form of meaningful work. And harmonic currents can be described with the man of the mathematical concept of the Fourier series, which basically indicates that if you have any periodic waveform that's periodic in nature, it can be described as a infinite sum of sine waves in integral multiples called harmonics. And what does this mean? Well, if you think about, if you were to view on an oscilloscope what the line power here in North America looks like, It's a nice 60 Hz smooth sine wave.
And as soon as you start drawing current from this source that is not linear, that's drawing current in a discontinuous fashion, you are distorting the waveform. And all of a sudden the Fourier series comes into play, where that waveform is now described not just as the fundamental 60 Hz sine wave waveform, but additionally integral multiples of that waveform at higher frequencies.
So in, in variable frequency drives, we typically are concerned primarily with the 5th, 7th, 11th and 13th harmonic. But what does this mean? Well, if our base frequency of the, the power delivered here is 60 Hz, the fifth harmonic would be 5 times 60, for example, or 300 Hz. These are low frequency disturbances.
In fact, in cases where you have harmonics presenting in the field that are possibly problematic, you can sometimes hear these frequencies when you're near a transformer in the form of audible noise.
So these are low frequency disturbances that ultimately can cause voltage distortions, which is often a symptom of excessive harmonic content.
[00:05:50] Speaker A: Okay, so Don, let's stick with that theme. What are some of the practical symptoms of poor power quality?
[00:05:56] Speaker C: Yeah, I mean, I think, you know, to build on George's answer, I think there's also many forms of harmonic loads that we don't think about. So even your, your iPad or computer, those are all harmonic loads because they create harmonic burn. Obviously, the amount differs. But practical symptoms of poor power quality inside a building would be primary transformer failure. Right. So if someone's having a primary transformer that failed, then obviously they have a problem with the overall harmonic load content in their building. Is that very common? No, it's not very common, but certainly would Be an obvious red flag if the primary transformer fails or fails more than once.
Or if you have other equipment inside the building.
For example, not so common these days. But a time clock, that's a semiconductor based time clock, you could start the malfunction or other systems that are not functioning properly, it could be due to harmonic current that is interrupting their operation and creating some sort of malfunction.
[00:07:05] Speaker A: And Jordan, do you have experience with this too?
[00:07:08] Speaker B: Yeah, I was actually just thinking, Amara.
Well, to Don's point, he indicated that this doesn't happen very often. And I've been doing drives for over 20 years and this has happened. I've been brought into two field circumstances, two field issues where harmonics were contributing to anomalies which were disrupting other equipment. And one of them actually was just over a year ago. Last spring, I received a call. There was a pumping station in a remote area of New England. And when the drive, a 75 horsepower drive, was running, they were unable to turn on the lights in the facility. The lights wouldn't come on and some of the metering equipment was malfunctioning.
And usually by the time it gets to my level, a few people have taken a look at an issue. So I presented for a field visit and we started doing an investigation. Well, this, this pump house had been in operation for over 20 years. It had had this drive for a long time and been working fine.
But in the previous fall. So a few months earlier, before winter set in, this pump station had undergone an upgrade where the fluorescent lights were replaced with LED lighting.
The antiquated flow metering equipment was updated with higher tech equipment with remote monitoring capabilities.
And everything worked well over the winter. And in the spring, all of a sudden, things started acting up and come to find out with investigation that there were excessive harmonic currents which resulted in voltage distortions at this pumping station. And probably they had been there all along over the 20 years. But it wasn't until older, less sensitive equipment had been upgraded with newer equipment such as LED lighting and remote monitor capable flow meters that these harmonics actually presented an observable problem.
And what was even more interesting is that the new station functioned great over the wintertime and only started presenting issues in the spring. Well, that's because as we learned over the winter, they were running electric heaters keeping the place warm. And an electric heater is an example of a beautiful linear load which when added to the load of the drive, diluted the effect of the harmonic content and the voltage distortions went away. It wasn't until the Spring, when things warmed up, the heaters were shut off, that these problems presented themselves.
[00:09:50] Speaker A: So that can't be too unusual. Jordan, what installation environments are pretty commonly experiencing these negative outcomes from harmonics? What else?
[00:10:02] Speaker B: Well, that's an interesting question, Amara, because.
And looking back over my career, the first decade was spent pretty much dealing with heavy industries, so cement plants, aggregate plants, customers, where it was a pretty tough industrial environment. And in selling and supporting variable frequency drives into that environment over a decade I never heard a word of Harmonix because all these facilities, especially at the time, didn't have any sensitive equipment. So as long as the transformers had ample sizing, it was, it wasn't an issue. But a number of years ago, especially after I joined Yaskawa, I started being exposed to different markets such as the medical, commercial, so schools and universities, high tech customers, where you have customers in the robotics business, where all of a sudden you have these installation environments with very sensitive equipment, in the case of hospitals, MRI machines, or in a high tech manufacturing environment, very sensitive equipment. So I became more aware of power quality in general. And it's those environments where you need to be especially mindful about when you're designing a system, making sure that you're accounting for all the loads, balancing linear and nonlinear loads, and, and in the case where you may have an issue and you know, specifying proper mitigation.
[00:11:42] Speaker A: Right, good point. So Don, to continue again on that train of thought, what solutions are practical and realistic?
[00:11:51] Speaker C: Yeah, I mean one of the things that we've seen the last, even two years during COVID was people re you using facilities that were previous office buildings, now they're now laboratories or other research facilities and they're putting the kinds of equipment that Jordan was talking about into those facilities and they were having problems with power quality. So the biggest thing you can do to actually fix this, you know, from, you know, what is the silver bullet and the silver bullet really is to have a bigger building transformer that is connected to the power utility. If you want your biggest bang for the buck, you buy a bigger transformer and the problem goes away.
But what we see, you know, routinely is that often on a new construction, it's all focused on the equipment and we can supply, our competitors can supply, everyone can supply equipment that meets the 5% EHDI. But it's really a mid spend of resources and biggest thing we need to do is figure out how to address this up front on a project so that we can do a good analysis of the actual building to determine what product should go in there.
And determine the best outcome.
[00:13:10] Speaker A: Okay. Okay. So speaking of analysis, Jordan, what's needed to accurately assess the impact?
[00:13:17] Speaker B: Yeah, Don really touched on that. It starts with a good understanding of your distribution transformer that's supplying the loads in question. So when, when you're evaluating a design, you take the one line diagram outlining all the different loads connecting, connected to the transformer, and then the data on the transformer itself, the kva, the impedance, all these characteristics are taken into consideration.
And it's also important to consider when outlining the loads on the transformer that there's all kinds of examples of nonlinear loads these days. Not just variable frequency drives, but LED lighting, large computer backup and power supplies, all kinds of, you know, switching power supplies out here on the market that can contribute to nonlinear loads which can result in, in harmonic distortions that are beyond an acceptable level. So you need a good understanding of your loads and gather the appropriate information from the manufacturer so that you can perform an analysis.
[00:14:31] Speaker A: Great, thank you. And Don, speaking of impact, I understand your kids are having a huge impact on your life.
[00:14:40] Speaker C: Yes, it's a great question.
So we are in the process of approaching empty nest territory. We still have a freshman in high school, but we're trying to figure out what to do later. But it's really interesting to watch the transition from teenager to young adult and try and support whatever it is they want to do in their world rather than tell them what to do.
It's an interesting balance.
I remember that time in my life and now that I'm experiencing from the other side certainly has its challenges in tempered responses.
[00:15:23] Speaker A: Oh yeah, sounds like it. And Jordan, you have a huge transition too. Your world is changing quite a bit. Are you excited about moving?
[00:15:33] Speaker B: Yeah, it's changing. Well, not just for myself. I'm married and have two children, two boys that are 10 and 12 years old. So this is a big change for the entire family. And the physical logistics of moving when you've lived in one jurisdiction. We've lived in New England for 18 years.
So moving to Wisconsin, there's a lot of physical stuff to arrange and sort through.
Fortunately, we've been able to procure a house here and everything looks good. And fortunately my boys are both excited about the relocation to Wisconsin. There's more much to offer here and very different things to do compared to being in New England. So they'll get to spend the second half of their childhood in a new environment and we believe it's going to be up and up.
[00:16:26] Speaker A: Well, it sounds like there is a lot going on with both of you. So thank you for focusing first on power harmonics. I really appreciate your time today.
[00:16:36] Speaker C: You're very welcome.
[00:16:38] Speaker B: Yeah, our pleasure.
[00:16:40] Speaker A: Excellent. Well, for more on power harmonics, motors and drives and similar topics, visit Consulting specifying
[email protected]. thank you so much for listening and catch you next time. Bye. Bye.
