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It was not clear how spinning motors & clever wiring stabilizes voltage near a load? I feel like I basically knew mostly everything in the video already but a key piece that you described was and still is obscured.
Can you do a video explaining how utility scale batteries manage reactive power? I understand they can react to reactive power much quicker to balance the system, which is why they're in such high demand to backup solar and wind. Also, it would be cool to cover where it makes the most sense to put batteries - near the load, near the source, a bit of both? Near the source makes sense to me for balancing solar and wind generation, and near the load makes sense to balance the amount of electricity flowing through the transmission lines. I think a bit of both makes the most sense to keep the power through the transmission lines constant.
Hi Grady. As a retired power utility engineer in Scotland, I'd like to congratulate you for such an amazing video that incorporates all the main concepts of the AC power system in about 20 minutes. A lot of former colleagues couldn't explain these concepts as clearly and succinctly as you have done here. Well done!
Happen so BUT It would have helped had he said at the outset 'the flow rate or current is measured in or is called (or SOMETHING like that) AMPs Cos he talks about current flow never mentioning AMPs then shows equations with AMPs but no currants
Funnily I’ve been writing a script this past week about this same topic, but on the National Grid and its history too. Stay tuned, I’ve got around 150 videos planned on the super grid, its history, components and future projects. From one commissioning engineer to another.
@@TS-jm7jm Yep, channel is brand new but currently writing scripts and gathering resources. I work for a certain company that makes access quite easy and myself and a few others are keen to teach and share our passion for the grid and its history.
I ran a 40 MW generator for twenty years, and was responsible for training many new operators. I really wish I had had this video available. I can’t count the amount of time I spent trying to explain VARs, and why it was necessary to comply with utility voltage orders. VARs are compensated by over or under exciting the generator field. How far to over or under excite comes in the form of a voltage order from the utility. Another problem generators have when exceeding the power curve is heat. The further out you move on the curve, the more heat generated inside the generator windings. A large part of generator design is the centrifugal force of the rotor spinning. The materials can only stand so much before flying apart. Heat weakens the materials making catastrophic failure more likely. Also, wires have their own resistance, and resistors convert current to heat. More current, more heat. You can see this with a little patience. On a summer day, use a tripod to take a picture of the wires between to transmission towers around 2:00 PM when load is highest. Take another around midnight at the same spot. You will see that the wire sags several feet when under high load. A wire sagging into a tree was the initiator for the Northeastern blackout in 2003. It caused a ground fault which tripped a generator. This caused an under voltage which tripped several surrounding generators, which tripped more generators, which cascaded and ended up tripping several states worth of power grid. Grady has an excellent detailed video on this. It is titled something like “What really happened in the 2003 blackout”.
Power systems engineer here. This video is a triumph, so concisely covering an astounding range of core power engineering concepts with remarkable approachability. Thank you for doing this public service for our industry.
Well, he didn't cover the different inductive and LC reactors out there, but then, that's well beyond the scope of the audience and target information. I still remember calculating power loading and balancing to prove out energy consumption and heat for a data center I was working in. Ended up rebalancing a few racks that were a bit excessive on one branch or another. Then, a well meaning Lieutenant overspecced the cooling system by a factor of over 3, resulting in frozen AC...
I fully agree, this video made it click so much it almost hurt. Shame that TH-cam encourages clickbait titles that make gems like these much harder to find.
I'm a student at college studying electrical installation. Would you mind giving me some pro tips on learning and the potential best career path to take please? There's so much choice and it all seems so daunting and complicated, as it stands I'm solely aiming for a qualification but want more to aim for ie a well paid and hands on career
This (no pun intended) just lit SO many lightbulbs for me. I've only ever tried to think about power factor in an industrial context - not a class or lecture, or any full description of the concept and I've been frustrated that I didn't get it. All the stuff I've been able to find online gives you a pile of equations stripped down for utility and zero intuition for why they work (or even what they're doing). Your animated graph with the power going negative along with the idea of energy being temporarily stored for a fraction of a phase was all I needed for everything to click into place. Now I'm going back to the rest of the internet to see if I can grasp the power triangle better with a new mental model... Thank you!!!
I think that it was the realization power flow wasn't constant (and can reverse) over the course of a period was the key for me. The complete "AC" explanations are super helpful for calculating stuff with phasors, but man do they sweep so much under the rug when you're trying to learn!
yeah, power factors, reactive power and thermodynamics.. Think of an idle transformer connected to mains. Massive current + full voltage but no power consumed except due to unwanted resistance..
Your channel's example of electric traveling through a line like water with it 'sloshing back and forth' before settling changed the way i looked at electricity
@@errhkaoutside of transformers, you can use the water in pipes to explain a surprising amount of electrical engineering. Including stuff like switching power supplies (ram pumps), semiconductor wizardry (valves), capacitors (water tanks/towers), inductors (pipes with moving water) and it all translates really well qualitatively.
Im an electrical Engineer from germany working in a big Industrial company. We use on site compensating in the low voltage sector (230/400v) which also allows our on site transormer stations to have a greater margin of operation. The compensators are basically just banks of capacitors swtiched on by big contactors row by row to keep the power factor above 0.9 for each transformer individually as here you also dont pay for the reactive power anymore. As most loads are asynchronus motors that dont see rappid switching, these relay stations can keep up relatively quickly. Thing is you can't compensate to a power factor of 1. That creates a resonating curcuit between the load and the compensator and can lead to voltage spikes.
Interesting. Do the compensators pay for themselves by raising the power factor, or is it mostly about that increased operating margin for the transformers? Greater efficiency both ways, I guess.
I once worked at a factory in Denmark with huge ovens to melt iron for iron casting. Each oven had a dedicated room, full of industrial capacitors, to compensate for the power factor. I'm an electrician, btw. There's a reason why many home electrical components, like fluorescent tube lights have capacitor parallel to the coil, that generates the high voltage. It's to compensate for the power factor. Not that I don't think you know this, you do of course, but the average person doesn't. It's actually law, that electronics and so on must provide a power factor. And manufacturers must do their best, to minimize the power factor. I kind of cringe sometimes, when I see TH-camrs measure how much a computer uses of energy, by using one of those cheap watt-o-meter or similar, that do not compensate for the power factor.
@@qcsupport2594 I can't quite remember, but I think the factory I mentioned, paid something like $15.000 in electricity bill per month or week. Without capacitor compensation, the bill could easily have been 30% larger. Those huge ovens had a massive coil around them in the bottom, to melt the metal. That coil only went 1 3/4 rounds around the ovens. That's insane! Almost a complete short circuit.
Here in Brazil, where I do cotton gin projects, it´s the same. The end user installs bank of capacitors to correct the power factor according to the motors in use.
@@akyhneI think the harmonics are a bigger issue for power factor and power quality then the reactance of the capacitor in the computer power supply. This video only focused on linear power factor caused by passive components and not non linear power factor caused by non linear loads such as LEDs and switched mode power supplies.
15:05 I was having trouble understanding how generating more power in the system wouldn't help deliver the power but the analogy of a burnout actually helped lol.
Excellent explanations! I’ve worked as an Operator at a large power plant, adjusting generator excitation to compensate for VARs as needed by the grid. The best analogy I’ve heard for explaining reactive power is a beer mug: the beer is the real power carried by the mug, and the head on the beer is the reactive power. It isn’t useful for anything, but the mug still has to hold it all!
It is a lovely analogy - tangible, important and visualisable. A straight induction powered motor is a badly poured Guiness. Adding capacitors is like employing decent bar staff - more beer in the same glass.
@@andrewharrison8436 and as the OP suggests with the excitation... with too many barmaids, they get silly and hard to keep in check... not enough barmaids and business gets slow... too much capacitance and you cant reduce the excitation sufficiently. rotor field adds to stator field. too much inductance and you cant get enough excitation. rotor field subtracts from stator field.
As an electrical technician I truly admire the way you explained the main concepts about AC and Power factor. These takes several years of studying to understand all those things and yet you managed to explain that very simply and clearly. Great job!
Great explanation thanks. I was control room operator at a large nuclear power plant. Very complicated work. Did cross training at load dispatch. Much respect for what they need to consider every second of the day. The gave us reports on solar magnetic disturbances. We have procedures to cope with the Induced currents. VARS to me is like hysteresis in valve testing. Best video on this topic I've ever seen!
That was a really excellent description. And even though it was only in passing, you even mentioned the single most important equation from ohms law... the power-resistance equation (P = I^2 * R)... very few TH-cam personalities mention that equation or even realize that it exists or what it means. So lets expand on it a bit to round things out. This equation governs power lost to heat in a circuit, wire, or cable. As you can see, it is non-linear with current. There are some major consequences to it being non-linear with current: * When you double the voltage you halve the current to make the same power, but LOSSES wind up being only 1/4th. In otherwords, increasing voltage vastly, vastly reduces losses. Not just by a little, but by a lot. * This is why transmission lines on the grid pump the voltage up. If you increase the voltage from 120V to 120,000 volts... so you increase the voltage 1000 fold, you decrease the power losses by a million-fold. 1000000-fold lower power losses. Lower losses == far higher efficiencies. This is why transmitting power over the grid is so efficient. The U.S. grid, on average, exceeds 90% efficiency. * This also works for DC power and is why pumping up the DC voltage leads to far higher efficiencies and lower losses. A 48V battery system is 16x more efficient than a 12V battery system, for example. -- So even though ohms law seems linear on its face, it isn't when it comes to resistance and power. The voltage drop across a resistance (across a cable) is linear, but the power loss is not linear. e.g. 1 amp flowing through 1 ohm of resistance will drop the voltage by 1V. If you are pumping 10V into the circuit (10V x 1A = 10W), you have 9V on the other end and lose 10% of your power to heat. But lets say you want to transmit 10W and are pumping 100V into the circuit? Now you are multiplying the voltage by 10 but you are ALSO reducing the amperage by a factor of 10 to get the same 10W. 100V @ 0.1A through the circuit (10W). Now the voltage drop is only 0.1V instead of 1V, and it is relative to 100V instead of 10V. Thus the power loss isn't just 1/10th, it's 1/100th. Losses go by the SQUARE of the current. * People often wonder why AC wiring has low losses when not under load. I mean, the waveform is constantly switching back and forth and that does mean that there is current sloshing around. The power equation is the reason. Because the current is so low, the losses are even lower. If the current sloshing about is, say, 0.001A then the power losses wind up being I*I*R = 0.001 * 0.001 * R which is 0.000001 * R. * Reactive power only flows along the current path. If HOUSE A generates reactive power, HOUSE B won't see it. But the GENERATOR and all components and cabling in between the GENERATOR and HOUSE A will see it and have to deal with it. * The reactive power caused by a large number of point loads combines into essentially one power factor by the time it gets back to the substation, which the substation can compensate for. Each point load provides its own contribution but they all essentially combine into one phase angle. And there you have it. -Matt
Thanks Matt. I worked as a water chemist in a thermal electric power plant in Eastern Newfoundland. In summertime , periods of low heating and low Air Conditioning load , The plant would run one alternator as a ‘ synchronous condenser’ I asked our engineering dept why we ran that unit that way but never did get a satisfactory answer/ understandable answer I think I understand it now. If you got any water treatment issues let me know. Tks Ed
Learned something today I didn't know I needed or wanted to know. Very interesting. Thanks. Than thanks Grady for your excellent yet simple explanation.
Wow. Thank you for all the amazing detail. It’s so fascinating to me the difference between Us and British Consumer power grids because of the different delivery Voltages. Yet another difference in application that I forgot the history of… down a rabbit hole again 😅❤
This video explained volt-amps, real power, apparent power, reactive power and power factor better in a few minutes than my instructors did in multiple years.
@@ShainAndrews yeah detecting basic rethorical stylistic choices, such as hyperboles for exaggerated effect, on the internet is hard, I know. But have you tried being a happier person before? Gives you a much better outlook in life
Many instructors, having a Ph.D. in Electrical Engineering, tend to cover the material in an overly mathematical manner. I think they have a hard time comprehending the fact that students who have lesser abilities than theirs just can't handle the math, especially on their first attempts.
Its job qualification. You have to understand reactive power to be a power engineer. On the other hand, if you understand entropy, you can be a mechanical engineer.
I'm a mechanical engineer and have taken a class which focused heavily on power circuits. I know the power triangle and understood the concepts of both reactive power and power factor Our instructor essentially told us that running with too much reactive load damages equipment This is the first time I've heard it explained as "actual power that has to be stuffed through the wires, but isn't converted to useful work" It makes *so much sense*
There is a simple way to remember the phase relationships for capacitance and inductance. ELI the ICE man. ELI: Voltage leads current in an inductor (L is the symbol for inductance). ICE: Current leads voltage in a capacitor (C is the symbol for capacitance). I learned this from my father who spent 26 years in the US Navy as an electronics technician, more than 60 years ago when I was just 16.
Nice piece. It brought back memories. Years ago I designed industrial control systems and we had a client paying huge power factor penalties due to some very large motors. (one was 300 hp) We installed a capacitor bank which cost many thousands of dollars (440 system) but their payback was less than a year from lower utility bills.
My boss is always talking about some soft starts he put on some massive well pumps in Texas years back. In their case I think he said payoff was somewhere around the same. I think he says 16 months, I'll have to ask. He went to college with the dude that was high-ish up at the water authority. Their draw on startup was absolutely astronomical.
@@goosenotmaverick1156 My understanding of soft starters is that they lower in rush power demand. They are not for reducing reactive power or improving the power factor. The power factor penalty or reactive power cost are different than peak power demand cost. Peak demand is important. But peak demand is a different subject than reactive power. They have different solutions. That is my understanding.
@@erniecolussy1705 yeah now that you bring it up, It wasn't necessarily a relevant story 😂 I gotta drink my coffee before hopping in the comments. Lol my bad folks.
@@pocketpc_ Not totally an apples to apples comparison since industrial 440V 3 phase motors are quite a bit different from DC driven EV motors but it is amazing how much power they get out of EV motor systems. Of course, you are pulling power from a $15k+ battery pack and using huge amounts of electricity to charge them. I haven't studied EV charging stations but I am asssuming they ramp up the charge at the beginning to avoid huge inrush currents.
Back in high school during the late 1970s we had 2 physics teachers that used simple demonstrations to begin complex lessons. They didn't grade on a curve, 80% of the classes received at least a B grade. When ideas are reduced to their simplest concepts people get it. Another great video making complex ideas easy to comprehend. Thanks Grady!
As usual, well thought out and presented. One thing though. Lightly loaded transmission lines are capacitive. The point where they are VAR neutral (neither producing nor consuming VARS) is called the surge impedance loading point or SIL. I'm a system operator for a 6500 -MW system, and we constantly have to adjust our reactive resources depending on loading and the time of day.
Awesome information as usual! I should quit and let you do electronics!! Regarding 17:03, I would say having just capacitors on power lines works the same as just inductors on the line, in that they also create reactive power and so drawing more current than needed from power lines. So they don't boost voltage, but if more capacitance is used than inductance, the reactive portion of current goes right back up and the capacitors are not helpful anymore. So we need to switch them out/in to make sure they almost exactly cancel out the effect of inductors.
Capacitors do actually boost voltage because powerlines have very little resistance and lots of reactance. So real power impacts voltage less than reactive power. Capacitors increase voltage, inductors decrease voltage and resistive load doesn’t affect voltage all that much
@@ElectroBOOM It's not that capacitors raise voltage themselves, but by providing reactive power, they raise the power factor, reducing the voltage drop across the line. Resulting in a higher voltage at the capacitors. From an operator's perspective, we're just maintaining system voltage; as long as voltage is in band, power factor is too
@@Henrik0x7F That's rather surprising, power lines are just straight conductors, and straight conductors is how one usually reduces stray inductance, so effectively your saying a straight bit of wire is more lossy due to inductance rather than resistance - even if the frequency is extremely low like 50 or 60Hz, I'm more accustomed to MHz signal losses, 50/60Hz is all but DC in that realm.
Making sure that no power bounces back from the load is also super important in data transmission. You can't get a clean signal when there are reflected signals bouncing around the circuit. Instead of power factor you look at the reflection coefficient.
An easy way to remember the phase relationships is: ELI the ICE man. In an inductive circuit (L) voltage (E) leads current (I). In s capacitative circuit (C) current (I) leads the voltage (E).
From an electrical engineer who once worked in electric metering: BRAVO. Very good entry-level presentation of this topic. I'm sharing this with some of my non-technical colleagues.
In the paper industry we use synchonous motors to refine pulp (grind). Those synchronous motors appear as capacitive loads and there are usually 6 1MW motors per paper machine. So that's 6MW to counter act all the inductive loads that are also running in the mill. Saves the mill quite a bit of money to use those motors.
Interesting form of self regulating the reactive power in your system. I'm guessing those synchronous motors have an excess of field excitation for them to appear as capacitive loads?
@@ASAVSP I've never worked with synchronous motors that big, but motors in the 100 kW range are started with a pony motor that spins the synchronous motor up to operating speed so it can be started without excitement. 🙂
The concern is that someone will buy a transformer, and hook up a massive polarized cap based on the 5 seconds he shows a 0.1uf cap plugged into a model circuit being supervised by an action figure? I think that risk is pretty dang low.
@@mikescholz6429one of my favorite things about Sim City 2000 was the ability to load the cities into Sim Copter. Games were so much better back then, I swear.
Excellent video! As a retired electrical engineer with a power systems specialty, it is always great to see such a clear and easy to understand treatment of a very complex subject. Keep up the good work!
I was a kid when this outage happened and I still remember it. I now work for Hydro-Québec and it's really interesting to see you explain what happened and how it works. Thank you!
16:40 Your picture showed a concentrated solar plant. That power generator does have inertia because it generates steam and spins a turbine, unlike solar panels.
Well yes, but not quite. The sun light is used to boil water to create steam. The steam then spins a turbine and the turbine spins the power generator that produces the electric power. The way you described it, with the power generator generating the steam would cause a lot of damage in the power plant
@@XEinstein my understanding is the concentrated sun light is actually used to heat molten saline, which is then used to heat the water to steam. That's even more inertia thermally stored.
Hello Grady, You did an excellent job of explaining cos φ (power factor) in a graphical fashion, with the phase lag of 90 degrees caused by a reactive load. The problem of explaining the difference (in AC circuits) between active and reactive power is because power is a vector, not a simple number. This is why I prefer to precede all the explanations about reactive power with a crash course on complex numbers and vectors calculations, together with some basic trigonometry. After just two days of math lessons, every aspiring technician is able to operate advanced power equipment in the power station. The problem of solar coronal mass ejections, is that they induce asymmetries in the sinusoidal waveform, which are seen - across the power lines and the power transformers - as a DC component, which is almost impossible to manage. Greetings, Anthony
The day they taught us budding EE's phasors was a day that I'll always cherish because it massively simplified equations. Before that you had fractions with real and imaginary numbers that had to be added, subtracted, multiplied, and divided. With phasors it was vastly simplified. The multiplication of phasors involves the multiplication of the magnitudes of the vectors, and the addition of the phase angles. Division was the same but the subtraction of the denominator's phase angle from the numerator. Addition and subtraction were similarly simplified.
I might be dumb and inexperienced, but can't you manage DC component with coupling caps? Although that might not be practical with the high power the grid transfers
@@creeper6530 With signal transmission, caps will do a fine job, but not in very high power 60 Hz systems. In power grid applications, the problem is that on a Y 3 phase system. the center connection is grounded. Any DC component is just passed to ground, through the transformer, giving an offset magnetic field, in addition to the normal magnetics in the transformer. When these big, expensive transformers are designed with little overhead, the extra DC current will cause the core to saturate, creating, essentially a short. Older equipment was not able to deal with it. In a Delta configuration, this does not happen, but the voltage spikes could still be a problem.
The solar flares we had a couple of weeks ago were as strong as the ones you talk about in this video and we can see that everyone is more prepared as we didn't lose power this time here in the province of Québec.
6:13 That type of capacitor is known as an "electrolytic" and isn't meant to have an AC voltage on it. The side with the black stripe marked "-" needs to be negative with respect to the other terminal. If you put reverse voltage on it (as happens 60 times a second with AC from the mains), it can explode and shoot hot capacitor fluid at you. Be careful.
@@hiddenInsight486 There are electrolytic capacitors used for AC circuits but they are not polarized, they are specifically designed for AC operation. @Ronathangator is correct, the polarized capacitors Grady is using are specifically meant for DC application only. I couldn't see the voltage rating of the capacitor in the video but if left in Grady's AC circuit long enough it will overheat and fail, venting its electrolyte and potentially blowing apart at the vent. There are inexpensive non-polarized capacitors available that he could have used for this demonstration.
@@hiddenInsight486 I'm an electrical engineer working in the field of power engineering for the last 35 years, I can assure you that if you apply a reverse polarity voltage to a polarized electrolytic capacitor (as Grady did in his demonstration) it will fail, long before its design life. It won't fail immediately but it will fail in a short time, I've witnessed it. If you apply a DC bias to a polarized ALEL cap and add an AC component on top of the bias such that it never sees a negative voltage that is fine (so long as the AC component doesn't exceed the ripple current rating of the cap). There are ALEL caps that are specifically designed for operation on AC circuits where the applied voltage transitions from positive to negative and back again but those caps don't have polarity markings.
When I was a kid, a friend of mine got into electronics kits. One day, when I was at his place, he asked if I wanted to see something cool. Then he closed the curtains, turned off the light, and flipped the switch on a capacitor he had connected to mains power. Fireworks! Suddenly I was interested in electronics too.
This really comes to mind a wind storm that knocked out power to huge swaths of power to my town. You cant just turn everything back on. It takes a lot of monitoring and careful decisions.
Grady, I actually have a recent (couple weeks ago) story related to this. I was having issues with a very sensitive piece of network hardware having issues at a certain time of night each night, and it was related to the incoming power having a fluctuation during the power company's nightly switchover of certain power conditioning equipment. It was extremely difficult to track down, but it was interesting when your video just backed up what we had discovered via troubleshooting. We solved it by using a local power conditioning powerstrip for the sensitive piece of equipment.
Hi Grady. I just found you today. I was a power lineman in the Air Force. Power for the Base and the Air field was my responsibility. WoW. This is Excellent. Most educational and enjoyable. Thank You.
I love the before and after. Clean shaven gradey - suddenly becomes 3 days of no sleep and no shave . Good work dude, keep it up. Love the videos, and how simple they are made.
Worked with a client whose industrial plant was being hit with severe power factor penalties on their utility bill. Switched capacitor banks was the solution we came up with. It paid for itself in under two years and continues to reap the benefits!
During the recent geomagnetic storm, I had a GFCI-protected circuit that tripped multiple times. Enough current was induced in the wiring to exceed the allowable fault current and make the circuitry in the breaker read it as a neutral-to-ground short condition. These things are no joke!
Grady, As a mechanical engineer we had to learn these basic electrical fundamentals, but AC power, reactive power, and all that goes with it never clicked until this video! Excellent job on presentation and practical visual examples.
After 4 years of college i finally understand reactive power.... Why did they only explain it from a math perspective and not explain what reactive was..... it was just how to find it with math and not what it is. THANK YOU GRADY!
There is nothing like demonstration of foundation realities to bring life to math. I anticipated my high school physics course would be wonderful; instead it was simply more dry math exercises .
Ex-Navy / current power plant operator for the last 30 years. I only have one thing to say… where have you been?!!!! I have started send a link to this video to all the new kids apprenticing here at our 1250MW plant. Explaining power factor / vars was the worst thing to attempt. You have made it so easy to understand. Thank you so much!!!!
I love how every one of your videos feels like you're just casually explaining something you find interesting You're not screaming into a ring light like a boomer at the drive through, you're not condescending, just...explaining. Brilliant.
Excellent video. It's a great refresher of power engineering for my EE / Electric Vehicle Engineering thesis defense. You explained it much better than the professor.
I live at Sydney and the grid here is a big mess. Never built as a two way system and much of the bigger power stations built for base load demand are now closed in the chase for ‘green energy’. I put on 10kW solar system and all that seems to do is makes the electricity company profit as they pay me peanuts for my feed in power. It’s basically criminal behaviour
I have worked and played with electronics since I was six, including some years in the power industry. Best simple explanation of VAR I have ever seen.
16:40 shows an image of a heliostat solar power plant, which uses a steam turbine and itself has inertia, when describing the lack of inertia from solar PV. It's an odd choice in yet another excellent video.
I have several things i would like to point out I think your battery is undervoltaged, normally your battery should not go below 11.5V, but it could also be a 5 cell lead acid battery which is not common, so i suggest checking and since undervoltage can damage batteries And some mistakes in the video 1. The reason the light bulb got more resistance was not due to higher voltage, but due to the filament getting hotter, most materials when hotter get more resistive 2. Please do not put an electrolytic capacitor in an AC circuit unless you want to be electroBOOM 3. 9:20 is a brushed DC motor Otherwise it is accurate, and i do not expect a civil engineer to know every detail about electronics
In europe a power factor under 0.85 is deemed unacceptable and the price for reactive power is quite severe. You may even end up paying 2-3 times as much on reactive power depending on power factor
I did my under grad as an electrical engineer and promptly started doing software after graduation. This was weirdly nostalgic and informative great video. Rarely has anyone presented this material in such a digestible and engaging manner.
I studied this stuff years ago in college and worked on SCADA systems for years at a very large utility in the US. This is one of the best videos I’ve ever seen on power system control. I wish they had videos like this in college or for teaching new employees when they joined our department. Very good work!
The Tesla battery in Australia does more for grid stability than it does for supplying backup power like everyone thinks it’s was installed for. It’s insane how much $ they make by just securing South Australia’s power network stability
no no. "The Tesla battery in Australia is meant to be for grid stability, it’s insane how much $ they make playing the energy market with it." While I am to lazy to look up the numbers on the SA battery at least two batteries in QLD have been fined for not being able to supply the "stability" they were contacted for because they were playing the energy market.
@@InvisageStudios Yes its a wonderful well planned system we have in place. As I said in another comment, I have three generators. Mostly(though not completely in fairness) because our wonderful first world grid.
And that rating is wrong, or, at least, confusing. VA is the only meaningful number. You can plug in resistive load up to VA, obviously exceeding W rating, but that's totally fine. W rating is probably VA*PF, and PF is assumed to be "typical for PC" or "typical for SMPS". There is no such thing as "typical load" though. The most interesting part of this is that on DC side you still have to supply real power, which combined with low-voltage battery, voltage drops on wires and connectors and battery discharge curve(s) leads to significantly lower on-battery times and shorter battery life span
Great video Grady! Took me back to my AC transmission class in college. Your 20-minute explanation was much clearer and more succinct than my professor's was back then. He did the best he could in the day only using a blackboard.
This video does an amazing job explaining reactive power! One nitpick regarding the resistance of incandescent bulbs: the resistance really changes with temperature. Increased voltage => increased current => increased power released as heat. In general, it is true that resistance changes with voltage because increased heat => higher temperature => higher resistance.
Way back when I was young and pretty fresh out of electronics 101 class, I learned that I could use small electrolytic capacitors to reduce the ignition noise imparted to my new car stereo. I can't remember exactly how I wired the two of them but I remember after soldering them together and touching one end of a wire leading to them to the power source the the tip of the wire glowed red. To which I immediately pulled it away. Curiosity told me to touch it again and it glowed red again but this time also with a surprising loud pop right under my chin. After I regained my composure and investigated, one of the capacitors had exploded. Good stuff!!
I have tried a few times to wrap my head around power factor and reactive power and could never really understand why it was a problem at all. This is the first time its actually made sense to me. Thanks!
Where I work there are a bunch of large motors, the power factor is controlled by a large cabinet containing large chokes and capacitors . It keeps the power factor at .98.
Which means the motors and other loads don't send the reactive power all the way back to the power plant, instead keeping it local to your shop, by 'sending' it to the components in that cabinet - and they then again draw it back in the next half cycle.
All bullshit about electricity is to hide the imaginary concept. Do anyone really understand what imaginary number really represents or means nope. But question is why imaginary number used in electrical engineering at all there is no need of imaaginanary numbers at all. Imaginary numbers are used to obscure the concept rather than telling the truth. Unit circle is sufficient to tell about electricity and without Imaginary concept you can see what's going on
Great explainer! I worked for a company that installs temporary power across the globe. Several successful power installs in Australia and also a few proposals to send some equipment to act as synchronous condensers. IIRC, it was after Teals installed all those battery banks when we started making proposals. Cool to see everything I've witnessed working at that company condensed into this video.
I have a degree in electrical and computer engineering. I never understood the issue with reactive power. Your graph of power vs voltage and current varying by phase made it all click to me. I wish someone showed me that in school (not that I actually use my degree...)
I'm not even halfway through the video, and I'm at the oscilloscope part. That's amazing. I've read about the lag with voltage/current before, and seen the graphs of it, but really never understood how that works, but this demonstration made it "click" for me, thank you so much! Looking forward to the rest of the video, too.
Hi Grady, as a power system engineer I think your description of the role and flow of reactive power within the grid is very well done. It can be difficult to explain it to people who aren't familiar with the topic, and I think you have done an amazing job. Well done!
As someone who sells utility scale power factor correction for a living, I have always struggled to explain to my non-technical children what I do. This video is the best explanation I have yet seen. Very well done.
I counted one commercial at the end. In this world it seems fair to get some kind of compensation for your effort. If you really can't stand the commercial, just turn the video off. That's pretty simple.
@@maynardjohnson3313 maybe for you. Depends on when you're watching it among many mother factors as to how many ads you receive and how long they are. If I'm watching videos late at night I get 3 minute ads every few minutes.... Probably because they think you will fall asleep and let them play at night. So it's nothing to do with the quality of the content. I just use ad blocker because of these tactics. Like I said, I would watch reasonable ads to support the creator. But not the amount of garbage they throw at you
At 02:11 the needles on the meter is moving backwards and forwards at the same time. That really is confusing, lol. Brilliant video, the content just get better and better.
@@drsnapid Well you must be 100 years old or live wayyyy out in the sticks. You aren't going to try and tall us your power has got cheaper and your grid more reliable if you live an a major city are you? Even our governments have admitted that, that's why they are giving you money for your power bills. Oh and why is it NSW is paying to keep the largest coal fired power station online?
@@stusue9733 strange assumptions but yes I live out in the sticks with 25000 others and I can't recall the last power problems that weren't directly related to storms. Power bills I'm not sure about because I've had rooftop solar a long time and can't remember the price before I got that to compare.
@@drsnapid Well yes if you aren't on the eastern grid all bets are off. So by your own admission. "can't remember the price before I got that to compare." This would be a lie. ""the opposite seems true " But don't worry, I have a solar system to and get $0.60 infeed tariff. Yeah it's crazy. Great system we have planned out here. "It's cheaper to make your own" that's how the first world works isn't it?
Great description! I;ve been an electrical engineer since the 70s and worked primarily in heavy industry. I teach these days and your description is one of the best I have seen to describe the basics without getting lost in the math. Not really a power distribution guy, but you still need to understand how it all applies to the end users. The plant I worked at in my later years was a greenfield plant using about 40MW. And we were just on the finishing end of steel production. We had 2 double ended 138kv subs. and loads of PF correction banks at the 13.8kv level. Our big integrated plants covering around 10 square miles or so. made this little greenfield look tiny! With several Co-Gen operations. They had their own power department groups and soe impressive manned AC stations. We had a small group who took care of al the 13.8kv and below distribution, while the utility company managed the 138kv stuff. So I had exposure, but wasn't a power distribution guy. I had more than enough to worry about with all the lower voltage subs and all the operating automation. It's not uncommon for big industry to mirror power distribution levels with the electrical workforce responsivities. I always found power distribution interesting but found the controls side of things to have greater variety in the typical challenges. People don't realize that electrical engineering has at least half a dozen or more of major specialty fields. .Depending on where you work, there may or may not be a lot of crossover, Electrical engineering is really about as diversified as the medical fields.
That was the best explanation on electricity basics I have ever seen. This needs to be shown at the beginning of elctric engineeering classes, so the lecture can expand on it with the actual math. On a side note, the relationship between real, reactive and apparent power can be easily remembered with a glass of beer. The golden beverage itself is the real power, foam is the reactive power and the height of the beverage and foam together is apparent power.
Thank you for all your videos. I’ve come to realize that in every day life sometimes people don’t fully understand concepts and when they are asked questions they really struggle to explain things. Your channel keeps me motivated and excited in the pursuit of long life learning. You remind me how much I love STEM and it helps me push through the daily grind. Keep up the good work.
Grady, as an experienced industrial electrician that has a good understanding of power factor, I must say your explanation is fantastic! It's something even most sparkies don't understand properly so kudos. It's interesting how the US manage power factor for big factories, the electricity suppliers having capacitor banks to manage it for their customers and charging them accordingly. Here in NZ most factories have onsite PF correction units that consist of a bunch of massive capacitors and inductors that can be switched on and off via a controller that monitors the overall PF of the incoming supply and corrects it accordingly. Most are set to run with a 0.9-0.95 PF. They will be charged accordingly if their PF correction unit fails but as far as I know NZ doesn't have big grid PF correction. I could be wrong, I've never worked in distribution.
Hi Grady, just wanted to let you know that I love the way you explain many different aspects of engineering. Even complex issues are becoming straightforward thanks to you and your commitment. Greetings from power electronics engineer from Poland! :)
Just want to say that this series on electrical infrastructure is an absolute blessing. They are so hard to understand without these animations and explanations.
⚡Here's my entire power grid series: th-cam.com/play/PLTZM4MrZKfW-ftqKGSbO-DwDiOGqNmq53.html
🌌Get Nebula using my link for 40% off an annual subscription: go.nebula.tv/Practical-Engineering
Why weren't there no SCADA tripped? I remembered to set it awl up!
This is great! Thanks for collecting and sharing this with us!
My 5 year old loves seeing your videos!
It was not clear how spinning motors & clever wiring stabilizes voltage near a load?
I feel like I basically knew mostly everything in the video already but a key piece that you described was and still is obscured.
So these problems would not occur over HVDC lines, right ?
Can you do a video explaining how utility scale batteries manage reactive power? I understand they can react to reactive power much quicker to balance the system, which is why they're in such high demand to backup solar and wind. Also, it would be cool to cover where it makes the most sense to put batteries - near the load, near the source, a bit of both? Near the source makes sense to me for balancing solar and wind generation, and near the load makes sense to balance the amount of electricity flowing through the transmission lines. I think a bit of both makes the most sense to keep the power through the transmission lines constant.
Hi Grady. As a retired power utility engineer in Scotland, I'd like to congratulate you for such an amazing video that incorporates all the main concepts of the AC power system in about 20 minutes. A lot of former colleagues couldn't explain these concepts as clearly and succinctly as you have done here. Well done!
Happen so BUT
It would have helped had he said at the outset 'the flow rate or current is measured in or is called (or SOMETHING like that) AMPs
Cos he talks about current flow never mentioning AMPs then shows equations with AMPs but no currants
Funnily I’ve been writing a script this past week about this same topic, but on the National Grid and its history too. Stay tuned, I’ve got around 150 videos planned on the super grid, its history, components and future projects.
From one commissioning engineer to another.
@@TheElectricBrityou going to upload these too your channel?
@@babboon5764 They might have been raisins though 🤔
@@TS-jm7jm Yep, channel is brand new but currently writing scripts and gathering resources. I work for a certain company that makes access quite easy and myself and a few others are keen to teach and share our passion for the grid and its history.
I ran a 40 MW generator for twenty years, and was responsible for training many new operators. I really wish I had had this video available. I can’t count the amount of time I spent trying to explain VARs, and why it was necessary to comply with utility voltage orders. VARs are compensated by over or under exciting the generator field. How far to over or under excite comes in the form of a voltage order from the utility.
Another problem generators have when exceeding the power curve is heat. The further out you move on the curve, the more heat generated inside the generator windings. A large part of generator design is the centrifugal force of the rotor spinning. The materials can only stand so much before flying apart. Heat weakens the materials making catastrophic failure more likely.
Also, wires have their own resistance, and resistors convert current to heat. More current, more heat. You can see this with a little patience. On a summer day, use a tripod to take a picture of the wires between to transmission towers around 2:00 PM when load is highest. Take another around midnight at the same spot. You will see that the wire sags several feet when under high load.
A wire sagging into a tree was the initiator for the Northeastern blackout in 2003. It caused a ground fault which tripped a generator. This caused an under voltage which tripped several surrounding generators, which tripped more generators, which cascaded and ended up tripping several states worth of power grid.
Grady has an excellent detailed video on this. It is titled something like “What really happened in the 2003 blackout”.
is it what happened in Russia? the whole thing just got out of the hole and floodded the generators room... and the whole site...
@@AngryChicKen-VIP Don’t know that incident. Could you give more details?
What fuel did the generator run on?
@@SheeplandGovt Natural gas.
@@Simple_But_Expensive Thanks for your quick reply!
Power systems engineer here. This video is a triumph, so concisely covering an astounding range of core power engineering concepts with remarkable approachability. Thank you for doing this public service for our industry.
Well, he didn't cover the different inductive and LC reactors out there, but then, that's well beyond the scope of the audience and target information.
I still remember calculating power loading and balancing to prove out energy consumption and heat for a data center I was working in. Ended up rebalancing a few racks that were a bit excessive on one branch or another. Then, a well meaning Lieutenant overspecced the cooling system by a factor of over 3, resulting in frozen AC...
I fully agree, this video made it click so much it almost hurt. Shame that TH-cam encourages clickbait titles that make gems like these much harder to find.
There's another video about preloading bolted joints that is similarly awesome.
I'm a student at college studying electrical installation. Would you mind giving me some pro tips on learning and the potential best career path to take please? There's so much choice and it all seems so daunting and complicated, as it stands I'm solely aiming for a qualification but want more to aim for ie a well paid and hands on career
This (no pun intended) just lit SO many lightbulbs for me. I've only ever tried to think about power factor in an industrial context - not a class or lecture, or any full description of the concept and I've been frustrated that I didn't get it. All the stuff I've been able to find online gives you a pile of equations stripped down for utility and zero intuition for why they work (or even what they're doing). Your animated graph with the power going negative along with the idea of energy being temporarily stored for a fraction of a phase was all I needed for everything to click into place. Now I'm going back to the rest of the internet to see if I can grasp the power triangle better with a new mental model... Thank you!!!
I think that it was the realization power flow wasn't constant (and can reverse) over the course of a period was the key for me. The complete "AC" explanations are super helpful for calculating stuff with phasors, but man do they sweep so much under the rug when you're trying to learn!
yeah, power factors, reactive power and thermodynamics.. Think of an idle transformer connected to mains. Massive current + full voltage but no power consumed except due to unwanted resistance..
Your channel's example of electric traveling through a line like water with it 'sloshing back and forth' before settling changed the way i looked at electricity
@@AlphaPhoenixChannelit’s time for a new video on the subject (really loving your electricity videos)
@@errhkaoutside of transformers, you can use the water in pipes to explain a surprising amount of electrical engineering. Including stuff like switching power supplies (ram pumps), semiconductor wizardry (valves), capacitors (water tanks/towers), inductors (pipes with moving water) and it all translates really well qualitatively.
After working for 40 years in the energy industry, this is the best explanation of reactive power for laymen that I have encountered. Bravo!
Im an electrical Engineer from germany working in a big Industrial company. We use on site compensating in the low voltage sector (230/400v) which also allows our on site transormer stations to have a greater margin of operation. The compensators are basically just banks of capacitors swtiched on by big contactors row by row to keep the power factor above 0.9 for each transformer individually as here you also dont pay for the reactive power anymore. As most loads are asynchronus motors that dont see rappid switching, these relay stations can keep up relatively quickly.
Thing is you can't compensate to a power factor of 1. That creates a resonating curcuit between the load and the compensator and can lead to voltage spikes.
Interesting. Do the compensators pay for themselves by raising the power factor, or is it mostly about that increased operating margin for the transformers? Greater efficiency both ways, I guess.
I once worked at a factory in Denmark with huge ovens to melt iron for iron casting. Each oven had a dedicated room, full of industrial capacitors, to compensate for the power factor. I'm an electrician, btw.
There's a reason why many home electrical components, like fluorescent tube lights have capacitor parallel to the coil, that generates the high voltage. It's to compensate for the power factor. Not that I don't think you know this, you do of course, but the average person doesn't. It's actually law, that electronics and so on must provide a power factor. And manufacturers must do their best, to minimize the power factor.
I kind of cringe sometimes, when I see TH-camrs measure how much a computer uses of energy, by using one of those cheap watt-o-meter or similar, that do not compensate for the power factor.
@@qcsupport2594 I can't quite remember, but I think the factory I mentioned, paid something like $15.000 in electricity bill per month or week. Without capacitor compensation, the bill could easily have been 30% larger. Those huge ovens had a massive coil around them in the bottom, to melt the metal. That coil only went 1 3/4 rounds around the ovens. That's insane! Almost a complete short circuit.
Here in Brazil, where I do cotton gin projects, it´s the same. The end user installs bank of capacitors to correct the power factor according to the motors in use.
@@akyhneI think the harmonics are a bigger issue for power factor and power quality then the reactance of the capacitor in the computer power supply. This video only focused on linear power factor caused by passive components and not non linear power factor caused by non linear loads such as LEDs and switched mode power supplies.
15:05 I was having trouble understanding how generating more power in the system wouldn't help deliver the power but the analogy of a burnout actually helped lol.
in less layman terms it has to do with impedence matching and something called the Maximum power transfer theorem
@@WildEngineering jacobs law... or yeah, thevenin...
kirchoff also applies...
the generator is a resistor and the current also flows through it...
Excellent explanations! I’ve worked as an Operator at a large power plant, adjusting generator excitation to compensate for VARs as needed by the grid.
The best analogy I’ve heard for explaining reactive power is a beer mug: the beer is the real power carried by the mug, and the head on the beer is the reactive power. It isn’t useful for anything, but the mug still has to hold it all!
It is a lovely analogy - tangible, important and visualisable.
A straight induction powered motor is a badly poured Guiness. Adding capacitors is like employing decent bar staff - more beer in the same glass.
@@andrewharrison8436 and as the OP suggests with the excitation... with too many barmaids, they get silly and hard to keep in check... not enough barmaids and business gets slow...
too much capacitance and you cant reduce the excitation sufficiently. rotor field adds to stator field.
too much inductance and you cant get enough excitation. rotor field subtracts from stator field.
The froth on the beer; me too.
As an electrical technician I truly admire the way you explained the main concepts about AC and Power factor. These takes several years of studying to understand all those things and yet you managed to explain that very simply and clearly. Great job!
Great explanation thanks. I was control room operator at a large nuclear power plant. Very complicated work. Did cross training at load dispatch. Much respect for what they need to consider every second of the day. The gave us reports on solar magnetic disturbances. We have procedures to cope with the Induced currents. VARS to me is like hysteresis in valve testing. Best video on this topic I've ever seen!
I'd enjoy that job
That was a really excellent description. And even though it was only in passing, you even mentioned the single most important equation from ohms law... the power-resistance equation (P = I^2 * R)... very few TH-cam personalities mention that equation or even realize that it exists or what it means. So lets expand on it a bit to round things out.
This equation governs power lost to heat in a circuit, wire, or cable. As you can see, it is non-linear with current. There are some major consequences to it being non-linear with current:
* When you double the voltage you halve the current to make the same power, but LOSSES wind up being only 1/4th. In otherwords, increasing voltage vastly, vastly reduces losses. Not just by a little, but by a lot.
* This is why transmission lines on the grid pump the voltage up. If you increase the voltage from 120V to 120,000 volts... so you increase the voltage 1000 fold, you decrease the power losses by a million-fold. 1000000-fold lower power losses. Lower losses == far higher efficiencies. This is why transmitting power over the grid is so efficient. The U.S. grid, on average, exceeds 90% efficiency.
* This also works for DC power and is why pumping up the DC voltage leads to far higher efficiencies and lower losses. A 48V battery system is 16x more efficient than a 12V battery system, for example.
--
So even though ohms law seems linear on its face, it isn't when it comes to resistance and power. The voltage drop across a resistance (across a cable) is linear, but the power loss is not linear. e.g. 1 amp flowing through 1 ohm of resistance will drop the voltage by 1V. If you are pumping 10V into the circuit (10V x 1A = 10W), you have 9V on the other end and lose 10% of your power to heat.
But lets say you want to transmit 10W and are pumping 100V into the circuit? Now you are multiplying the voltage by 10 but you are ALSO reducing the amperage by a factor of 10 to get the same 10W. 100V @ 0.1A through the circuit (10W). Now the voltage drop is only 0.1V instead of 1V, and it is relative to 100V instead of 10V. Thus the power loss isn't just 1/10th, it's 1/100th. Losses go by the SQUARE of the current.
* People often wonder why AC wiring has low losses when not under load. I mean, the waveform is constantly switching back and forth and that does mean that there is current sloshing around. The power equation is the reason. Because the current is so low, the losses are even lower. If the current sloshing about is, say, 0.001A then the power losses wind up being I*I*R = 0.001 * 0.001 * R which is 0.000001 * R.
* Reactive power only flows along the current path. If HOUSE A generates reactive power, HOUSE B won't see it. But the GENERATOR and all components and cabling in between the GENERATOR and HOUSE A will see it and have to deal with it.
* The reactive power caused by a large number of point loads combines into essentially one power factor by the time it gets back to the substation, which the substation can compensate for. Each point load provides its own contribution but they all essentially combine into one phase angle.
And there you have it.
-Matt
Thanks Matt.
I worked as a water chemist in a thermal electric power plant in Eastern Newfoundland.
In summertime , periods of low heating and low Air Conditioning load ,
The plant would run one alternator as a ‘ synchronous condenser’
I asked our engineering dept why we ran that unit that way but never did get a satisfactory answer/ understandable answer
I think I understand it now.
If you got any water treatment issues let me know.
Tks Ed
Amazing explanation. I remember learning this but totally forgot about it as they say you don't use it. You lose it.
Learned something today I didn't know I needed or wanted to know. Very interesting. Thanks. Than thanks Grady for your excellent yet simple explanation.
Wow. Thank you for all the amazing detail.
It’s so fascinating to me the difference between Us and British Consumer power grids because of the different delivery Voltages.
Yet another difference in application that I forgot the history of… down a rabbit hole again 😅❤
So the higher supply voltages in Europe gives them much better grid efficiency, right?
This video explained volt-amps, real power, apparent power, reactive power and power factor better in a few minutes than my instructors did in multiple years.
Took you multiple years... yeah that's an instructor issue for sure....
@@ShainAndrews yeah detecting basic rethorical stylistic choices, such as hyperboles for exaggerated effect, on the internet is hard, I know.
But have you tried being a happier person before? Gives you a much better outlook in life
Many instructors, having a Ph.D. in Electrical Engineering, tend to cover the material in an overly mathematical manner. I think they have a hard time comprehending the fact that students who have lesser abilities than theirs just can't handle the math, especially on their first attempts.
@@ShainAndrews more often than you apparently think
Grady, the retail “return policy” analogy for reactive power is outstanding!
Its job qualification. You have to understand reactive power to be a power engineer.
On the other hand, if you understand entropy, you can be a mechanical engineer.
I'm a mechanical engineer and have taken a class which focused heavily on power circuits. I know the power triangle and understood the concepts of both reactive power and power factor
Our instructor essentially told us that running with too much reactive load damages equipment
This is the first time I've heard it explained as "actual power that has to be stuffed through the wires, but isn't converted to useful work"
It makes *so much sense*
finally I understand cashback, it never made sense to me, its just reactive money.
Except Amazon proves the opposite. 🙂
@@monophoto1 What kind of engineer would someone be if they had a theoretical degree in physics?
This is probably the best explanation of power factor loss I have ever heard, and I worked in 3 phase commercial installations for 40 years.
There is a simple way to remember the phase relationships for capacitance and inductance.
ELI the ICE man.
ELI: Voltage leads current in an inductor (L is the symbol for inductance).
ICE: Current leads voltage in a capacitor (C is the symbol for capacitance).
I learned this from my father who spent 26 years in the US Navy as an electronics technician, more than 60 years ago when I was just 16.
Nice piece. It brought back memories. Years ago I designed industrial control systems and we had a client paying huge power factor penalties due to some very large motors. (one was 300 hp) We installed a capacitor bank which cost many thousands of dollars (440 system) but their payback was less than a year from lower utility bills.
My boss is always talking about some soft starts he put on some massive well pumps in Texas years back. In their case I think he said payoff was somewhere around the same. I think he says 16 months, I'll have to ask.
He went to college with the dude that was high-ish up at the water authority. Their draw on startup was absolutely astronomical.
@@goosenotmaverick1156
My understanding of soft starters is that they lower in rush power demand. They are not for reducing reactive power or improving the power factor. The power factor penalty or reactive power cost are different than peak power demand cost. Peak demand is important. But peak demand is a different subject than reactive power. They have different solutions. That is my understanding.
@@erniecolussy1705 yeah now that you bring it up, It wasn't necessarily a relevant story 😂
I gotta drink my coffee before hopping in the comments. Lol my bad folks.
Kind of crazy how a 300 hp motor sounds so big in the industrial world, but for an EV that's just business as usual.
@@pocketpc_ Not totally an apples to apples comparison since industrial 440V 3 phase motors are quite a bit different from DC driven EV motors but it is amazing how much power they get out of EV motor systems. Of course, you are pulling power from a $15k+ battery pack and using huge amounts of electricity to charge them. I haven't studied EV charging stations but I am asssuming they ramp up the charge at the beginning to avoid huge inrush currents.
Back in high school during the late 1970s we had 2 physics teachers that used simple demonstrations to begin complex lessons. They didn't grade on a curve, 80% of the classes received at least a B grade. When ideas are reduced to their simplest concepts people get it. Another great video making complex ideas easy to comprehend. Thanks Grady!
19:53 Got jumpscared by bearded Grady
Same thing happened to me when vsauce showed up without his beard
I support the beard
It was like a slap in an un-bearded face.
his beard looks like he's about to become Otto von Bismarck
- How long did it take to make this episode?
- Well sonny, I started when I was a teen and I managed to finish it just before retiring.
As usual, well thought out and presented. One thing though. Lightly loaded transmission lines are capacitive. The point where they are VAR neutral (neither producing nor consuming VARS) is called the surge impedance loading point or SIL. I'm a system operator for a 6500 -MW system, and we constantly have to adjust our reactive resources depending on loading and the time of day.
I just want to thank you for continuing to produce interesting content in a professional way.
Awesome information as usual! I should quit and let you do electronics!!
Regarding 17:03, I would say having just capacitors on power lines works the same as just inductors on the line, in that they also create reactive power and so drawing more current than needed from power lines. So they don't boost voltage, but if more capacitance is used than inductance, the reactive portion of current goes right back up and the capacitors are not helpful anymore. So we need to switch them out/in to make sure they almost exactly cancel out the effect of inductors.
Capacitors do actually boost voltage because powerlines have very little resistance and lots of reactance. So real power impacts voltage less than reactive power. Capacitors increase voltage, inductors decrease voltage and resistive load doesn’t affect voltage all that much
@@Henrik0x7F 🙂 That doesn't make sense, but thanks for the feedback!
@@ElectroBOOM It's not that capacitors raise voltage themselves, but by providing reactive power, they raise the power factor, reducing the voltage drop across the line. Resulting in a higher voltage at the capacitors. From an operator's perspective, we're just maintaining system voltage; as long as voltage is in band, power factor is too
@@ElectroBOOM I mean, try it out in spice or draw some vectors.
@@Henrik0x7F That's rather surprising, power lines are just straight conductors, and straight conductors is how one usually reduces stray inductance, so effectively your saying a straight bit of wire is more lossy due to inductance rather than resistance - even if the frequency is extremely low like 50 or 60Hz, I'm more accustomed to MHz signal losses, 50/60Hz is all but DC in that realm.
Making sure that no power bounces back from the load is also super important in data transmission. You can't get a clean signal when there are reflected signals bouncing around the circuit. Instead of power factor you look at the reflection coefficient.
Data transmission is a lot more complicated than power transmission.
matched load!
@@kazedcatoh thats for sure, the faster you go the more relevant the bouncing back gets.
An easy way to remember the phase relationships is:
ELI the ICE man.
In an inductive circuit (L) voltage (E) leads current (I).
In s capacitative circuit (C) current (I) leads the voltage (E).
Oh I so remember that mnemonic.
I always used the word CIVIL when teaching Power Systems to CIVIL engineering majors - "in a C, I leads V but in an L, V leads I" !
I learned that in Circuit I my first year in college... Lets see Motion Flux Current or Mary's.... um ah...
From an electrical engineer who once worked in electric metering: BRAVO. Very good entry-level presentation of this topic. I'm sharing this with some of my non-technical colleagues.
In the paper industry we use synchonous motors to refine pulp (grind). Those synchronous motors appear as capacitive loads and there are usually 6 1MW motors per paper machine. So that's 6MW to counter act all the inductive loads that are also running in the mill. Saves the mill quite a bit of money to use those motors.
Interesting form of self regulating the reactive power in your system. I'm guessing those synchronous motors have an excess of field excitation for them to appear as capacitive loads?
Thats really cool! Starting them must be exciting lol
@@ASAVSP I've never worked with synchronous motors that big, but motors in the 100 kW range are started with a pony motor that spins the synchronous motor up to operating speed so it can be started without excitement. 🙂
When he connected the polarised capacitor i expected an electroBOOM moment😅
Honestly, that's so dangerous, he should probably take the video down so people who don't know any better don't set fire to their houses.
The concern is that someone will buy a transformer, and hook up a massive polarized cap based on the 5 seconds he shows a 0.1uf cap plugged into a model circuit being supervised by an action figure? I think that risk is pretty dang low.
Nah. Learn from mistakes is good(?)
@jodosh The risk is someone will plug an electrolytic directly into a wall outlet without the high impedance of the small transformer.
Having been there and done that many moons ago, I was quite nervous for his fingers.
6:01 Grady trips over and inexplicably acquires an English accent.
Maybe that's why all villains in American movies have English accents...
Got possessed by the ghost of photonicinduction
I think grady sounds like "brains" from kids show thunderbirds.
Grady was the tripped breaker
Grady temporarily became Brady!
When you’re 10 years old and want to be the best developer, but SimCity residents won’t let you because of power plants.
When you’re 12 years old, with SimCity 2000 and a Game Shark, you become God.
It doesnt improve much when you graduate and get a job as a designer, take it from me :-)
@@jonbruford7950 you mean a lot of RFI? lol
@@mikescholz6429one of my favorite things about Sim City 2000 was the ability to load the cities into Sim Copter.
Games were so much better back then, I swear.
@@cruisinguy6024💯
Thanks! I enjoy learning from your channel.
Excellent video! As a retired electrical engineer with a power systems specialty, it is always great to see such a clear and easy to understand treatment of a very complex subject. Keep up the good work!
I was a kid when this outage happened and I still remember it. I now work for Hydro-Québec and it's really interesting to see you explain what happened and how it works. Thank you!
16:40 Your picture showed a concentrated solar plant. That power generator does have inertia because it generates steam and spins a turbine, unlike solar panels.
Hahaha, good catch!
Well yes, but not quite. The sun light is used to boil water to create steam. The steam then spins a turbine and the turbine spins the power generator that produces the electric power. The way you described it, with the power generator generating the steam would cause a lot of damage in the power plant
@@XEinstein thanks Einstein, the generator definitely does not generate the steam. I don't see how anybody would assume that.
@@XEinstein if there is excess power produced, why not run the generators in reverse to consume it on site?
@@XEinstein my understanding is the concentrated sun light is actually used to heat molten saline, which is then used to heat the water to steam. That's even more inertia thermally stored.
Hello Grady,
You did an excellent job of explaining cos φ (power factor) in a graphical fashion, with the phase lag of 90 degrees caused by a reactive load.
The problem of explaining the difference (in AC circuits) between active and reactive power is because power is a vector, not a simple number.
This is why I prefer to precede all the explanations about reactive power with a crash course on complex numbers and vectors calculations, together with some basic trigonometry.
After just two days of math lessons, every aspiring technician is able to operate advanced power equipment in the power station.
The problem of solar coronal mass ejections, is that they induce asymmetries in the sinusoidal waveform, which are seen - across the power lines and the power transformers - as a DC component, which is almost impossible to manage.
Greetings,
Anthony
The day they taught us budding EE's phasors was a day that I'll always cherish because it massively simplified equations. Before that you had fractions with real and imaginary numbers that had to be added, subtracted, multiplied, and divided. With phasors it was vastly simplified. The multiplication of phasors involves the multiplication of the magnitudes of the vectors, and the addition of the phase angles. Division was the same but the subtraction of the denominator's phase angle from the numerator. Addition and subtraction were similarly simplified.
I might be dumb and inexperienced, but can't you manage DC component with coupling caps? Although that might not be practical with the high power the grid transfers
@@creeper6530 With signal transmission, caps will do a fine job, but not in very high power 60 Hz systems. In power grid applications, the problem is that on a Y 3 phase system. the center connection is grounded. Any DC component is just passed to ground, through the transformer, giving an offset magnetic field, in addition to the normal magnetics in the transformer. When these big, expensive transformers are designed with little overhead, the extra DC current will cause the core to saturate, creating, essentially a short. Older equipment was not able to deal with it.
In a Delta configuration, this does not happen, but the voltage spikes could still be a problem.
This reminds me of the relativistic energy equation where mc2 squared plus pc squared is total energy squared.
been in Electrical trades for years. never fully grasped Reactance until now.. you have a good ability of explaining things clearly..
One of your best videos! Been in HVAC for 25 years and I dont think ive ever heard someone explain it as well as you did.
The solar flares we had a couple of weeks ago were as strong as the ones you talk about in this video and we can see that everyone is more prepared as we didn't lose power this time here in the province of Québec.
6:13 That type of capacitor is known as an "electrolytic" and isn't meant to have an AC voltage on it. The side with the black stripe marked "-" needs to be negative with respect to the other terminal. If you put reverse voltage on it (as happens 60 times a second with AC from the mains), it can explode and shoot hot capacitor fluid at you. Be careful.
They are used in AC circuits all the time
@@hiddenInsight486 There are electrolytic capacitors used for AC circuits but they are not polarized, they are specifically designed for AC operation. @Ronathangator is correct, the polarized capacitors Grady is using are specifically meant for DC application only. I couldn't see the voltage rating of the capacitor in the video but if left in Grady's AC circuit long enough it will overheat and fail, venting its electrolyte and potentially blowing apart at the vent. There are inexpensive non-polarized capacitors available that he could have used for this demonstration.
@@JeffCurtisIflyHG you are quite mistaken. Electrolytic can be used in AC perfectly fine.
@@hiddenInsight486 I'm an electrical engineer working in the field of power engineering for the last 35 years, I can assure you that if you apply a reverse polarity voltage to a polarized electrolytic capacitor (as Grady did in his demonstration) it will fail, long before its design life. It won't fail immediately but it will fail in a short time, I've witnessed it. If you apply a DC bias to a polarized ALEL cap and add an AC component on top of the bias such that it never sees a negative voltage that is fine (so long as the AC component doesn't exceed the ripple current rating of the cap). There are ALEL caps that are specifically designed for operation on AC circuits where the applied voltage transitions from positive to negative and back again but those caps don't have polarity markings.
When I was a kid, a friend of mine got into electronics kits. One day, when I was at his place, he asked if I wanted to see something cool. Then he closed the curtains, turned off the light, and flipped the switch on a capacitor he had connected to mains power. Fireworks!
Suddenly I was interested in electronics too.
This really comes to mind a wind storm that knocked out power to huge swaths of power to my town. You cant just turn everything back on. It takes a lot of monitoring and careful decisions.
Grady, I actually have a recent (couple weeks ago) story related to this. I was having issues with a very sensitive piece of network hardware having issues at a certain time of night each night, and it was related to the incoming power having a fluctuation during the power company's nightly switchover of certain power conditioning equipment. It was extremely difficult to track down, but it was interesting when your video just backed up what we had discovered via troubleshooting.
We solved it by using a local power conditioning powerstrip for the sensitive piece of equipment.
Hi Grady. I just found you today. I was a power lineman in the Air Force. Power for the Base and the Air field was my responsibility. WoW. This is Excellent. Most educational and enjoyable. Thank You.
I love the before and after.
Clean shaven gradey - suddenly becomes 3 days of no sleep and no shave .
Good work dude, keep it up.
Love the videos, and how simple they are made.
Worked with a client whose industrial plant was being hit with severe power factor penalties on their utility bill. Switched capacitor banks was the solution we came up with. It paid for itself in under two years and continues to reap the benefits!
I am retired electronics technician and this was a great refresh of stuff I learned a long time ago.
During the recent geomagnetic storm, I had a GFCI-protected circuit that tripped multiple times. Enough current was induced in the wiring to exceed the allowable fault current and make the circuitry in the breaker read it as a neutral-to-ground short condition. These things are no joke!
Grady, As a mechanical engineer we had to learn these basic electrical fundamentals, but AC power, reactive power, and all that goes with it never clicked until this video! Excellent job on presentation and practical visual examples.
thank you once again for being our engineering teacher Grady!
Hi youtube
I didn't realize TH-cam had a channel...
bring back the dislike count
my man got a comment from youTube themselves. Grady is a true legend
"...unless you trip over all the cords" Brilliant. Just brilliant. Made my day.🤣
After 4 years of college i finally understand reactive power.... Why did they only explain it from a math perspective and not explain what reactive was..... it was just how to find it with math and not what it is. THANK YOU GRADY!
There is nothing like demonstration of foundation realities to bring life to math. I anticipated my high school physics course would be wonderful; instead it was
simply more dry math exercises .
Ex-Navy / current power plant operator for the last 30 years. I only have one thing to say… where have you been?!!!! I have started send a link to this video to all the new kids apprenticing here at our 1250MW plant. Explaining power factor / vars was the worst thing to attempt. You have made it so easy to understand. Thank you so much!!!!
I love how every one of your videos feels like you're just casually explaining something you find interesting
You're not screaming into a ring light like a boomer at the drive through, you're not condescending, just...explaining. Brilliant.
Yeah; i think the motor-starting rated electrolytics have a differently configured/finished oxide insulator coating.
@@TomMcinerney-g9b Was this comment meant for somewhere else? lol
In your demo it would be better to put non-polarized capacitor into AC circuit.
Unless he's striving to become ElectroBOOM
Excellent video. It's a great refresher of power engineering for my EE / Electric Vehicle Engineering thesis defense. You explained it much better than the professor.
I live at Sydney and the grid here is a big mess. Never built as a two way system and much of the bigger power stations built for base load demand are now closed in the chase for ‘green energy’. I put on 10kW solar system and all that seems to do is makes the electricity company profit as they pay me peanuts for my feed in power. It’s basically criminal behaviour
I have worked and played with electronics since I was six, including some years in the power industry. Best simple explanation of VAR I have ever seen.
16:40 shows an image of a heliostat solar power plant, which uses a steam turbine and itself has inertia, when describing the lack of inertia from solar PV. It's an odd choice in yet another excellent video.
Well it is about renewables. The details are different.
(Grady is Civil -- so the EEs cut him a break -- those details are just trickicity and sunshine to him ;P )
I have several things i would like to point out
I think your battery is undervoltaged, normally your battery should not go below 11.5V, but it could also be a 5 cell lead acid battery which is not common, so i suggest checking and since undervoltage can damage batteries
And some mistakes in the video
1. The reason the light bulb got more resistance was not due to higher voltage, but due to the filament getting hotter, most materials when hotter get more resistive
2. Please do not put an electrolytic capacitor in an AC circuit unless you want to be electroBOOM
3. 9:20 is a brushed DC motor
Otherwise it is accurate, and i do not expect a civil engineer to know every detail about electronics
In europe a power factor under 0.85 is deemed unacceptable and the price for reactive power is quite severe. You may even end up paying 2-3 times as much on reactive power depending on power factor
I did my under grad as an electrical engineer and promptly started doing software after graduation. This was weirdly nostalgic and informative great video. Rarely has anyone presented this material in such a digestible and engaging manner.
I studied this stuff years ago in college and worked on SCADA systems for years at a very large utility in the US. This is one of the best videos I’ve ever seen on power system control. I wish they had videos like this in college or for teaching new employees when they joined our department. Very good work!
The Tesla battery in Australia does more for grid stability than it does for supplying backup power like everyone thinks it’s was installed for.
It’s insane how much $ they make by just securing South Australia’s power network stability
Common Elon W.
no no. "The Tesla battery in Australia is meant to be for grid stability, it’s insane how much $ they make playing the energy market with it."
While I am to lazy to look up the numbers on the SA battery at least two batteries in QLD have been fined for not being able to supply the "stability" they were contacted for because they were playing the energy market.
@@stusue9733 probably right, but if you knew how much they made - the fines would be petty cash
@@InvisageStudios Yes its a wonderful well planned system we have in place.
As I said in another comment, I have three generators. Mostly(though not completely in fairness) because our wonderful first world grid.
I had always wondered why UPSes were rated in both VA and W, until I learned about reactive power.
And that rating is wrong, or, at least, confusing. VA is the only meaningful number. You can plug in resistive load up to VA, obviously exceeding W rating, but that's totally fine. W rating is probably VA*PF, and PF is assumed to be "typical for PC" or "typical for SMPS". There is no such thing as "typical load" though. The most interesting part of this is that on DC side you still have to supply real power, which combined with low-voltage battery, voltage drops on wires and connectors and battery discharge curve(s) leads to significantly lower on-battery times and shorter battery life span
19:40 Man your beard grows fast. :p
Great video Grady! Took me back to my AC transmission class in college. Your 20-minute explanation was much clearer and more succinct than my professor's was back then. He did the best he could in the day only using a blackboard.
This video does an amazing job explaining reactive power!
One nitpick regarding the resistance of incandescent bulbs: the resistance really changes with temperature. Increased voltage => increased current => increased power released as heat. In general, it is true that resistance changes with voltage because increased heat => higher temperature => higher resistance.
That poor Hulk Hogan ... I'm sorry, Zap McBodyslam ... toy. :D
Electrodes attached to his McBoy parts. What's that about?
6:19 Did he really use a polarized capacitor on AC? 😂
Same thought, I was waiting for it to go pop
Way back when I was young and pretty fresh out of electronics 101 class, I learned that I could use small electrolytic capacitors to reduce the ignition noise imparted to my new car stereo. I can't remember exactly how I wired the two of them but I remember after soldering them together and touching one end of a wire leading to them to the power source the the tip of the wire glowed red. To which I immediately pulled it away. Curiosity told me to touch it again and it glowed red again but this time also with a surprising loud pop right under my chin. After I regained my composure and investigated, one of the capacitors had exploded. Good stuff!!
You should've used The Rock's action figure, because he's the most electrifying wrestler in all of sports entertainment
That joke is shocking
Good video!
I have tried a few times to wrap my head around power factor and reactive power and could never really understand why it was a problem at all. This is the first time its actually made sense to me. Thanks!
Where I work there are a bunch of large motors, the power factor is controlled by a large cabinet containing large chokes and capacitors . It keeps the power factor at .98.
Which means the motors and other loads don't send the reactive power all the way back to the power plant, instead keeping it local to your shop, by 'sending' it to the components in that cabinet - and they then again draw it back in the next half cycle.
Noticed how carefully he avoided mentioning imaginary power
All bullshit about electricity is to hide the imaginary concept. Do anyone really understand what imaginary number really represents or means nope. But question is why imaginary number used in electrical engineering at all there is no need of imaaginanary numbers at all. Imaginary numbers are used to obscure the concept rather than telling the truth. Unit circle is sufficient to tell about electricity and without Imaginary concept you can see what's going on
No mention at all of j nor i, i². Complex variables can change the taste of your coffee
The BEST explanation of VA I have come across.
Great explainer! I worked for a company that installs temporary power across the globe. Several successful power installs in Australia and also a few proposals to send some equipment to act as synchronous condensers. IIRC, it was after Teals installed all those battery banks when we started making proposals. Cool to see everything I've witnessed working at that company condensed into this video.
I didn't realize that Quebec was literally a capacitor
Oui
It took me a while to realize I am literally a capacitor.
I observe that in Quebec Monsieur Trudeau's policies are an arc fault, a direct short to ground
with no capacity to absorb, store or discharge real life variances to theory
PLEASE do not excite our Canadian friends ... as the Team Foreign Policy has already incited the Russians and Chinese.
0:08 That's why they tell you to never look at the sun, as it can have the consequence of geomagnetic storms hitting earth. ;-)
I have a degree in electrical and computer engineering. I never understood the issue with reactive power. Your graph of power vs voltage and current varying by phase made it all click to me. I wish someone showed me that in school (not that I actually use my degree...)
I'm not even halfway through the video, and I'm at the oscilloscope part. That's amazing. I've read about the lag with voltage/current before, and seen the graphs of it, but really never understood how that works, but this demonstration made it "click" for me, thank you so much! Looking forward to the rest of the video, too.
I'm not an EE but I thought I had a pretty good grip on how the grid works. Not even close. I learned a TON from this video. Great work, Grady!
Great video. The only thing I'm not clear on is how on earth Grady used an electrolytic capacitor on an AC power source without the cap blowing up 🤔
with low voltage and small duty times they can be used for much more than a textbook might suggest
6:02 Glad you survived! 🤭
*Applies AC to your electrolytic cap*
Hi Grady, as a power system engineer I think your description of the role and flow of reactive power within the grid is very well done. It can be difficult to explain it to people who aren't familiar with the topic, and I think you have done an amazing job. Well done!
Would have loved this when I did my apprenticeship in the early 2000s
6:30 - please tell me that's not an electrolytic capacitor.
Sorry to disappoint you.
As someone who sells utility scale power factor correction for a living, I have always struggled to explain to my non-technical children what I do. This video is the best explanation I have yet seen. Very well done.
Hi youtube, i will purposely never buy anything youve advertised to me due to your more and more intrusive advertising...
Me too
@@getsetgaming3475 I'll happily do 5 seconds at the start of a video or a skippable 30 seconds one, which I would sit through for worthy content.
TH-cam Revanced. Never watch an ad on TH-cam again.
I counted one commercial at the end. In this world it seems fair to get some kind of compensation for your effort.
If you really can't stand the commercial, just turn the video off.
That's pretty simple.
@@maynardjohnson3313 maybe for you. Depends on when you're watching it among many mother factors as to how many ads you receive and how long they are. If I'm watching videos late at night I get 3 minute ads every few minutes.... Probably because they think you will fall asleep and let them play at night. So it's nothing to do with the quality of the content. I just use ad blocker because of these tactics. Like I said, I would watch reasonable ads to support the creator. But not the amount of garbage they throw at you
Could you do a technical breakdown of turbo encabulators?
I’m waiting for you to say root mean square.
Root mean square
At 02:11 the needles on the meter is moving backwards and forwards at the same time. That really is confusing, lol.
Brilliant video, the content just get better and better.
How’d you grow a beard within 22 minutes? Keep it, looks good
i was going to say that tshirt and beard, you look ten years younger ;-)
As an Australian, please don't copy anything we're doing. Our power grid has never been less reliable or more expensive than it is now.
I have three generators. So that must be helping "net zero" lol
I'm also Australian and the opposite seems true for me. It's a big place
@@drsnapid Well you must be 100 years old or live wayyyy out in the sticks.
You aren't going to try and tall us your power has got cheaper and your grid more reliable if you live an a major city are you?
Even our governments have admitted that, that's why they are giving you money for your power bills.
Oh and why is it NSW is paying to keep the largest coal fired power station online?
@@stusue9733 strange assumptions but yes I live out in the sticks with 25000 others and I can't recall the last power problems that weren't directly related to storms.
Power bills I'm not sure about because I've had rooftop solar a long time and can't remember the price before I got that to compare.
@@drsnapid Well yes if you aren't on the eastern grid all bets are off.
So by your own admission.
"can't remember the price before I got that to compare."
This would be a lie.
""the opposite seems true "
But don't worry, I have a solar system to and get $0.60 infeed tariff. Yeah it's crazy. Great system we have planned out here. "It's cheaper to make your own" that's how the first world works isn't it?
It perplexes me that you are so handsome with a beard, yet choose to shave.
Maybe his wife ask him to
@@22981991 That would also perplex me, TBH
Who are you to tell ? Gae ni-
Great description! I;ve been an electrical engineer since the 70s and worked primarily in heavy industry. I teach these days and your description is one of the best I have seen to describe the basics without getting lost in the math.
Not really a power distribution guy, but you still need to understand how it all applies to the end users. The plant I worked at in my later years was a greenfield plant using about 40MW. And we were just on the finishing end of steel production. We had 2 double ended 138kv subs. and loads of PF correction banks at the 13.8kv level.
Our big integrated plants covering around 10 square miles or so. made this little greenfield look tiny! With several Co-Gen operations. They had their own power department groups and soe impressive manned AC stations. We had a small group who took care of al the 13.8kv and below distribution, while the utility company managed the 138kv stuff. So I had exposure, but wasn't a power distribution guy. I had more than enough to worry about with all the lower voltage subs and all the operating automation.
It's not uncommon for big industry to mirror power distribution levels with the electrical workforce responsivities. I always found power distribution interesting but found the controls side of things to have greater variety in the typical challenges.
People don't realize that electrical engineering has at least half a dozen or more of major specialty fields. .Depending on where you work, there may or may not be a lot of crossover, Electrical engineering is really about as diversified as the medical fields.
That was the best explanation on electricity basics I have ever seen. This needs to be shown at the beginning of elctric engineeering classes, so the lecture can expand on it with the actual math.
On a side note, the relationship between real, reactive and apparent power can be easily remembered with a glass of beer. The golden beverage itself is the real power, foam is the reactive power and the height of the beverage and foam together is apparent power.
Thank you for all your videos. I’ve come to realize that in every day life sometimes people don’t fully understand concepts and when they are asked questions they really struggle to explain things. Your channel keeps me motivated and excited in the pursuit of long life learning. You remind me how much I love STEM and it helps me push through the daily grind. Keep up the good work.
Thanks!
Grady, as an experienced industrial electrician that has a good understanding of power factor, I must say your explanation is fantastic! It's something even most sparkies don't understand properly so kudos.
It's interesting how the US manage power factor for big factories, the electricity suppliers having capacitor banks to manage it for their customers and charging them accordingly. Here in NZ most factories have onsite PF correction units that consist of a bunch of massive capacitors and inductors that can be switched on and off via a controller that monitors the overall PF of the incoming supply and corrects it accordingly. Most are set to run with a 0.9-0.95 PF. They will be charged accordingly if their PF correction unit fails but as far as I know NZ doesn't have big grid PF correction. I could be wrong, I've never worked in distribution.
Hi Grady, just wanted to let you know that I love the way you explain many different aspects of engineering. Even complex issues are becoming straightforward thanks to you and your commitment.
Greetings from power electronics engineer from Poland! :)
Just want to say that this series on electrical infrastructure is an absolute blessing. They are so hard to understand without these animations and explanations.