If it hasn’t been made readily apparent to you by now, power grids are astonishing marvels of technology and quite possibly one of the greatest engineering feats of history. Learning how these systems work is easy in theory, but in practice you will be shot if you try to screw around with at a power station. [Tim] and [Marissa] figured there must be an easier way to learn about power grids so they made their own. It’s small, but it still has everything you’d find in high voltage power lines, minus a hundred kilovolts or so.
This mockup of a power grid simulates a power plant by taking a normal DC motor and connecting that to an alternator and transformer. This is two of the simulated generation points, with the third AC/AC power supply serving as a reference generator for synchronizing phase and frequency. It’s only 12V at 60Hz, but it gets the job done.
A power grid isn’t power plants – there’s also transmission line theory. For this, [Tim] and [Marissa] have a few boards packed with inductors to simulate power lines. There are boards for simulated loads, and synchronization systems built on the MSP430.
In the video below, [Marissa] goes over all the ins and out of the system. It’s very well made and excellent for teaching something that can’t be demonstrated without a practical example.
The syncing on the audio is the worst o have ever seen.
My apologies. The demo is a bit brief, eh? This week we’re working on filming another video exclusively with demos of the project in action. Keep an eye out for the video sometime next week!
Interesting project, but she spent too much time explaining the project and there was almost no time spent actually seeing it work.
Thanks for the comment, Len. We were tight on time in making the video and wish we could have featured more on the actual project in action. As the project progresses we’ll post updates and be sure to show more live action now that we’ve explained the parts!
If you want to see something like this in operation:
https://www.youtube.com/watch?v=RGPCIypib5Q
Isn’t synchronization cool? We’re filming another (better) video this week with a longer, more descriptive demo which will certainly include synchronization.
Very nice explanation. This is exactly how it is done in the Navy when paralleling ships power with shore power. When we are ready to switch to shore power we place the electrical plant in “Droop mode” which lets the shore side control the frequency, the operator then throttles the steam generators until the synchrotron is at top dead center with all lights off. At that moment he closes the shore buss and takes the Steam generators off line.
At a military base, we had a syncro scope for paralleling back the 250kW cat diesel to the utility grid. That was an insane operation with a huge battery room for the 60hz generation and backup supply for critical systems for when the “shore power” went out and the diesel(s) would kick in. Yes, there was a 2nd diesel if we ever needed moar.
The panels for controlling the power had immense controls, highlighting the magnitude of forces involved. The “scope” was just a dial with needle sweeping, about 8 inches across. The knob for altering phase of each generator was at least 4 inches across.
You can simulate a grid power transmission line with a shorter conductor by just using a higher frequency. Because digital signals are constructed from harmonics, transmission line theory quickly (around 1 MHz upwards) becomes relevant for us ordinary mortal hackers.
Thanks for the comment. We chose 60Hz because we wished to simulate the real (US) power grid, which propagates at 60Hz, regardless of the challenges associated with lower frequencies and t-line RLC characteristics. That’s a very interesting method of grid simulation; we’ll certainly look into it as we move forward. Since our generators are mechanical (a motor spinning an alternator), we are far from MHz signals, but our digital elements of the project may find this useful. Thanks.
She mentions the fact that this class is the first introduction for students to launch pads, but if they are trying to visually learn transmission imho there is nothing that beats an old school synchronization panel board with big nobs, switchs, and a lead/lag/sync dial. Analog dials are cool…
The transmission line simulators are really interesting, and learning the effects of leading and lagging loads on a line are in a tactile way is invaluable. Especially in a world in which any house can now become a power producer.
Voltage rise is the new power utility engineers nemesis.
As a transmission engineer, I totally agree. The impacts of leading/lagging voltage and current and real/reactive power is incredibly important for students as they learn about the grid. That’s why we incorporated the sensor boards, where students can see, collect, and plot live data on voltage, current, phase angle, and so on. We hope to show that more clearly in our next video. But I do like the idea of analog dials…
The LaunchPads are really only there to (1) activate the mechanical generators and (2) operate the feedback control loop for frequency stability on each generator. The synchronization process is totally manual. This wasn’t too clear in the demo, but it will be in our next video. We wanted synchronization to be hands-on, not only because it’s more fun that way, but because synchronization is so fundamental to the grid… and so COOL!
I really wish The Internet as today and this project were around for our EE which included transmission lines. The prof was new and no one could understand the book (him or us). My peers and I were a sharp study group and were “on it” in every class. This one totally vexed us; no one cared about old fashioned things like power grids and generation.
I could forsee the “Idiocracy factor” coming. The more we take something for granted and forget about it, the worse the problem is later on when technology advances and all of a sudden you need to reinvent how that stuff works.
This is a very impressive project. I love that this gives a “hands on” look at power systems, minus the dangers associated with big power. Very well done.
Oh, and +1 for the inclusion of Lego. :D
Thank you so much for the positive feedback. We hope students learn a lot from this system.As for the Legos, we thought, how can we make this project more approachable…? It seems to have worked!
Am I the only one who started watching and kept watching it because of her? :D
This is a really good project and explained very eloquently.
Well done!
Thanks so much, Andrew!
True that. Boston University seems to excel at producing them… though it’s been 24 years since I was dating the Boston U gal I was working my co-op job with.
Bullshit like this is why we can’t get more women in engineering.
and this was meant to be a reply to the “beautiful women” comment but that seems to have been deleted. Pls delete mine too as it’s bad without context.
The overall concept is interesting but connecting electrolytic capacitors to a AC power grid seems like a bad idea.
Great catch! Yes, this proved to be a big challenge. With each AC cycle they break down just a bit. We followed transmission line theory’s model of an RLC lines, but hit some trouble with the caps (some explosions happened during initial testing…). We hoped to model the impact of capacitance on lines, but as you noticed, electrolytic wasn’t a good fit. We originally spec’d for surface mount caps on the PCBs but had some heating issues there. We also hoped to model capacitor banks that exist on the grid to provide and balance reactive power flow, but at this point that’s still in the works. Good catch. We’re working on fixing it!
Dear Power Pooches team,
This is an excellent project that demonstrated the majority of electrical engineering disciplines: analog, digital, power, control, DSP, embedded, MATLAB with real time data acquisition, and presentation. You’ve excelled at all of these, congratulations. The experience you gained here will help in all aspects of your future careers. When you’re interviewing make sure brag about all the concepts you’ve covered here. Its impressive and its what I want to hear about when I’m interviewing candidates. Marissa, I’d hire you on the spot if you presented yourself like you did here. Too bad the other team mates didn’t get in front of the camera. At this everyone should be selling themselves.
Glad to see BU is instilling EE basics.
Craig Hollabaugh PhD EE
Georgia Tech ’93
Thank you so incredibly much for the kind words, Craig. We’re so happy with how we’ve done and learned so much from this project. We actually just found out today that we are finalists in Texas Instrument’s University Project Competition! And here’s some new content (with demo) with the teammates, who were finally back from their travels:
https://www.youtube.com/watch?v=g9YEfh5UKC8
Again, thank you so much for the kindness and support. Go EE!
Marissa
To knock this presentation over the green wall, I’d suggest adding a system block diagram to the intro, then add highlighted areas of the block diagram in your topic segues. Need to lead the viewer through your system. Also, publish the URL to your final report and links to your linked in pages. Good luck at the TI competition and your EE futures.
Other than that, this is awesome presentation. Great work.