Hi, I’m Jon Ohman. Chief test pilot at GE Aviation, here at our Victorville flight test facility — and welcome to day four. Today I’m taking over all our social media channels to show you how we test our jet engines on our 747 flying testbed. My love for aviation came from my dad, he passed it on to me. And after serving as a pilot in the Marine Corps, that passion for aviation led me to here at GE. For me it’s always been about the people and the mission. And the mission of the team here is to ensure air travel is as safe as possible. But before we go up there, we have to spend a lot of time down here. Right here in the office. Before we do a test flight, we spend a lot of time here doing pre-flight planning, and a series of reviews to make sure everything we do is safe. Kind of like a pre-flight checklist. Let’s meet some of the team and see how it’s going. Hey Nate. Morning Jon! How’s the prep going for the next GE9X test campaign? Great! You mind talking us through the process a little bit? Of course, so one of the first step is we have what’s called a Flight Readiness review Where we get the entire team together, and walk through the plan that’s gonna take us to first flight. Next, we plan all the test cards with the engineering team. Then, once the engine shows up, we’re gonna integrate it to the airplane. We’re gonna test all those systems on a series of ground runs, and then we’re gonna have an aircraft safety review. Finally, we’re gonna have a pre-flight briefing with the entire test team on the morning of each flight. Alright, it looks like we’re almost ready! Thanks, Nate. No problem! Alright, now let’s see what it takes to mount one of these engines on to our 747 flying testbed. Hey Michael! Oh hey Jon! Hey, you mind telling us what we do to get this engine ready for tests? Yes, this is actually a CF6, but when we receive the 9X engine from PTO, we use an overhead crane to install it on the aircraft. Then, we will perform a high power ground run to verify we are safe and begin our flight campaign. This is a CF6 engine behind me, but the GE9X is actually way bigger. It has a fan diameter of 134 inches, that’s almost two of me. Alright, let’s go onboard the plane to check out the data console. But before we do that, we’re gonna get suited up. As you can see, this doesn’t look like
the inside of your standard 747. Instead of passenger seats, we have these rows of data collection consoles. Let’s talk to Jason and see what we do to get ready for a test flight. Hey Jason! Hey Jon! Hey, you mind telling us what we do to get ready to collect data for the test flight? Sure, what we’re doing now before the flight is doing our calibrations before we go to make sure that we’re gonna collect the most high-quality data that we can get, at up to two hundred thousand scans per second. So as you can imagine, that’s quite a lot of data. Looks like we’re almost ready for a flight. Let’s go and check out the cockpit. This is the cockpit of our 747 flying test bed. For the most part, it looks like a standard 747, but there are a few unique modifications. We use this flying testbed to test our engines in a variety of different tests. Everything from performance testing– to ensure that we’re getting the most fuel efficiency out of the engine possible, to operability testing, where we make sure that the engine can start under all kinds of conditions. So all of this testing is for the purpose of making sure that our engines are working normally, and safely for our customers. And that’s how we test the GE9X on our flying testbed. Thanks for joining us this week, I hope you enjoyed it.
Hi, I’m Kelley Dunham. Lead test engineer here at GE Aviation’s test operations in Peebles, Ohio. Welcome to day three: stand testing. Today, I’m going to show you how we assemble the final pieces of our GE9X engine, And then take it through a series of tests. So for that, let’s go check out our first stop: The Ed Spears Complex. So yesterday, you got to see development assembly of the GE9X in Evandale. And they send the propulsor here and we put on the final touches. So we install the fan case and the fan
blades. So now, it’s time to install the fan blades. So this is one of the 9X’s we’re prepping for tests. As you can see here on the side, This is all the instrumentation we’re putting on the fan case. Oh and look, it’s Phil. Hey Phil, how’s it going? It’s going good today! My name is Phil Ferguson, I’ve been here 15 years. Down here in the Fred building, we install the instrumentation, Anything to measure vibration temperature just to name a few, To ensure we have the best engine in the
world. Awesome! Thank you, have a great day. Behind me is the fully assembled GE9x. It has a total of 16 composite fan blades. Out here in Peebles, our facility is pretty big. In fact, it’s just over 7,000 acres. That means we can’t exactly just push the engine to the next stop. For that, we gotta hitch a ride. Before an engine is certified for flight, We have to take it through a series of rigorous testing. And when I say rigorous, I mean rigorous. Crosswind testing, hailstorm testing, hailstone testing, ETOPS, Performance testing, endurance testing,
block test, dynamics testing. Let’s head inside now to check out the control room where the testings actually done. I’m gonna introduce you to Nick, Who’s gonna tell us a little bit more about how we monitor tests while they’re running. Nick! Hi, I’m Nick– Test level owner here at site six. So today what we’re gonna do, we’re gonna run this vibe endurance check here, Make sure everything looks good in this engine I think we’re ready to go if you are. Alright, let’s do this! Let’s do it. Alright let’s do this. Vibe check Kelly? Vibes are good! Here we go, time is 14:18. Begin accel in three, two, one Vibe tests will be running for awhile, So let’s go check out some other engines that are running. This engine behind me is running power calibrations. That big dome you see over there is what we call the TCS dome or the turbulence control structure. Behind me are the two production test cells. So once the GE9X is the certified engine, All the engines will run through here for production testing. The great thing about the indoor test cells is that we can run no matter what the weather is. Rain, sleet, or snow, we can still run the engine. Thanks for following along today! I hope you enjoyed the inside look at how we test our GE9X engines Here at the Peebles test operations in Peebles, Ohio. Check back in tomorrow for on-wing
testing with our chief test pilot. See ya!
Hey there, I’m Aaron Perry, Development Assembly Mechanic here in GE Evendale on the GE9X. Welcome to day 2. So today I’m gonna take you through the process we use to take all these parts and make a GE9X development engine. Let’s go! The parts came from all over the world. Check it out. Booster came from Belgium. Fan Hub Frame came from France. Forward Cases came from Taiwan. CDN, United States of America. TCF, Germany. LPT, Italy. See I told you they came from all over the world. Looks like this engine needs a Lower Stator Case but before we can install that we got to go see the planner who’s developing the process. So now that we have the Lower Stator Case ready for assembly, we need our process, our instructions, our plan for making sure that it gets installed correctly. That’s where my buddy, Aaron Caskey, comes into play. Sup, Aaron! He’s a GE9X planner. He’s gonna tell you a little bit more about what he does. Oh yeah, so here we are developing a template to install the Lower Stator Case on the GE9X. But it’s not set in stone yet, have to bounce it back off Aaron to make sure it makes sense to him. Once we look at it and we determine that everything looks good and that the Stator Case assembly should go as expected, I’ll come back to Aaron and say, “let’s go to the next step.” Thanks, Aaron! Thanks, Aaron. So before we put this Lower Stator Case on, we got one more stop. We need to check with our Instrumentation Process Engineer, Freddy, to make sure he’s got all his hardware installed. Hey Fred. Hey Aaron. Currently working on installing light probes as you can see it’s on the outer case of that forward case and it’s all done right now. Let’s go install this thing! Alright, we’re ready to install the Lower Stator Case. We’re gonna take the Stator Case and I’m gonna put it on the engine right there. My buddy Mike is here to help us out. Hey Mike, introduce yourself. Yes, my name is Mike Whalen, and I’m an Assembly Mechanic with General Electric and I’ve been here seven and a half years. Alright Aaron, you ready? Let’s do it! Alright it looks like we’ve got this engine just about wrapped up and we wanna check with our Assembly Engineer to make sure all the paperwork’s in line before we ship it. Hey Anne! Just making sure everything’s checked off to ship. How’s it look? Looks good. Let’s ship it! So growing up, I always like space flight, space travel, aircraft, airplanes. That curiosity has stayed with me. Still fascinated with it, I still love it. And here I am, an aviation icon, GE Aviation, working in my hometown on the biggest, best jet engine manufactured today with the newest technologies. It’s the best place to work. Hey, thanks for watching how we put these beasts together. Come back tomorrow to see how we test them at Peebles. See ya.
‘To be notified of all Wirally updates,
do hit the bell icon.’ Good morning, sir.
– Who is this? – This is my first day here, sir. Oh, so you are the new joinee.
You needn’t call me sir, call me Kiran. Be seated. ‘Good morning, God. Currently, I’ve many problems.
Make sure I don’t get anymore current problems.’ Shit, it is ringing. What do I do?
I’ll ask him to answer. Ravi, you are so lucky.
You’re getting a call on your first day. Go for it. Hello?
– Is this the electricity department? – Yes, it is. There is power outtage, I’m stuck in a lift.
– You’re stuck in a lift? Just restore the power
for about 2 minutes and I’ll get out of this lift. Where are you calling from?
– From Apparaopeta. Which floor are you stuck in?
– In the 29th floor. The building which has 29 floors
has got no generator? That isn’t the point. Please, restore the power
for about two minutes and I’ll get out of this lift. Alright, I’ll send a person right away. 29 floors and no generator.
I’ll go see what I can do. I better rush. As it is his first day, he is excited. I sorted that issue, sir.
Shall I answer this call too? Have fun!
– Electricity department? – Yes. There has been a power outage.
‘Cruel Hubby Delicate Wife’ is being aired. If you don’t restore the power
in a jiffy, you are deadmeat. Sir, she says I’ll be deadmeat.
– Mom, turn off the fan. Save the backup on UPS
for me to watch the serial. And you, if you don’t restore the power
in another 3 minutes, you are dead. Mom, turn off the lights too.
– She wants to watch TV on UPS! Are you there? Do you follow?
– Yes, ma’am. Even the UPS has gone dead.
– Sir, why is the public so violent? Don’t worry. This is what soap operas
do to women. You’ll get used to it. This is the 33rd power outage
of the day. Sir, it is ringing again.
– I’ll take care of it this time. Electricity department?
– Yes. – There is a power outage in Champapet. Because of the thunderstorm last night, wires and poles
got damaged. Power won’t restore until tomorrow. What do I do till then?
– Sleep on the terrace. – What about the mosquitoes? Use All Out.
– How can I when there is a power outage? Light a Jet coil then.
– I can’t stand the smoke. – Use Odomos then. I don’t have Odomos at my place.
– Then go to hell! Don’t call us back again. Now hang up!
They take government employees for granted. You dealt with him so well.
– Soon, you will aswell. – I feel so charged up! I’m nervous even to take a look
at the electricity bill. Oh, Lord! I’ll call up and enquire!
– Since you are charged up, answer the call. Electricity Department?
– Yes. – Do you got AC at home? Yes. – A fridge? – Yes.
– A motor? – Yes. – A TV? – Yes. I even got oven, mixer and grinder at home.
Why do you ask and waste my time? How much is your electricity bill?
– Around Rs. 3000. At my place, I’ve one fan, two tubelights,
a portable TV and a fridge. How much do you think is my electricity bill?
– Around Rs. 2000. It is around Rs. 5000.
Even you got shocked, imagine my plight. What nonsense is that? I’m not even turning on
the only fan I have fearing the bill and I’m faning myself instead.
Rs. 5000 must be the whole neighbourhood’s bill. Let me raise a complaint on your behalf.
– I see. Tell me your meter’s number.
– EU49263BEU. I’ll send a line man to your place. He’ll take care.
– I raised a complaint two months ago. There has been no update since then.
All you people say is my complaint is under process. Hell with your bill! If my bill exceeds Rs. 1000 the next month,
I’ll break your transformer! Good Lord!
– What is it, Ravi? This man only has 4-5 appliances at home,
yet his bill is over RS. 5000. What a pity. Sir, it is ringing again.
– You go take a break. I’ll handle this one. Electricity Department?
– Yes. – We’ve no power for hours now! Where are you calling from, sir?
– From Nirmal, Karimnagar. From Karimnagar? Then call your local
electricity department, not us. Hell with your internal politics.
Give power back to us. You think power is some candy
to give you back instantly? Where did you find this number?
– I Googled for this number. I see. Call your local electricity department.
– Fine, you get them on line. I’ll talk to them. I’m not some telephone operator.
You call them up. Alright, atleast tell me what their number is.
– That’s better. Now hang up.
People think the current office is some customer care. What a wrong time
for a power outage! Electricity department?
– Yes, sir. There has been a power outage
in our hood for two hours. Where are you calling from, sir?
– Ahuti Nagar. – I see. Stay on line, sir. For how long has there been a power cut in Ahuti Nagar?
– For about 5 minutes. – That’s it? Power will be restored in 2 minutes.
– You’ll be dead if it won’t. What is the matter, Ravi?
– I’ve to teach this idiot a lesson. It’s been 2 minutes. Don’t you got no time sense?
But if I fail to pay the bill on time, you’ll fine me. Wait, stop there! Are you educated?
– I’m a post graduate. And yet you got no common sense?
– What nonsense are you talking? I’ll tell you what. In this city
3500 mega watts of power is used daily! What about the pollution it causes. Cut it. Just tell me when power would be restored.
– You idiots never change. Ravi, let’s go have a butter milk break.
– Sure, sir. Are you now chill? Take it easy.
I’ll answer the call. ‘Eletricity department?’ – Yes.
– ‘There is no power in my area.’ There is power everywhere in the city.
Where are you calling from? ‘Shanti Nagar.’
– There is power there. Give me your address. Alright, we’ll come there and check. It is better if he tags along.
Ravi, let’s go to Shanti Nagar. This is the address.
Mr Kiran, nice that there are no dogs in here. Are you the guys from electricity department?
– Yes? – There is power everywhere but in my house. Chill, chill.
– We are here to find out just that. He turned off the main supply.
– I’m shocked too. Turn it on. There is power everywhere else
because they didn’t turn off the main supply like you did. I turned off the main supply?
– Yeah and also wasted our time. Now I remember, I indeed turn off the main.
– What a prick this guy is. What in the world is that?
– Power theft. Let’s go catch him red handed. Lights, fans, tubelights,
more tubelights and more fans. Who is this little prick?
– Let’s ask him. Who are you two?
Who let the scavengers in? Hey, security! We’re from electricity department.
– What is the proof you aren’t lying? Fine, you aren’t lying. Why are you here?
– You are using so much electricity. And I’m also paying for it.
– Show me the bills. – I pay them online. Atleast show us the online receipts.
– There is no charge on my phone. You use so much power yet there is no charge
in your phone? Are you trying to fool us. Oh, yeah.
– You are busted. You are stealing power, aren’t you?
– No, sir! No, sir! No, sir! ‘No, sir!’. How long have you been staying here?
– Only for a year, sir. But my in-laws stayed here
for 2 years before I moved in here. You mean you’ve been stealing power
for 3 straight years? Busted!
– Mr Kiran, let’s teach this idiot a lesson. Go and pull out the fuse box. We’ll fine you
and teach you a good lesson for messing with us. You expect honest people to bear
the burden of your power consumption too? I’m sure, you’d have faced similar situations.
If you did, let us know in the comments. Also, do like, share and subscribe
Hey, there, guys. Paul here from TheEngineeringMindset.com. In this video, we’re going
to be looking at capacitors to learn how they work, where we use them, and why they are important. Remember, electricity is
dangerous and can be fatal. You should be qualified and competent to carry out any electrical work. Do not touch the terminals of a capacitor, as it can cause an electric shock. So, what is a capacitor? A capacitor stores electric charge. It’s a little bit like a battery, except it stores energy
in a different way. It can’t store as much
energy as a battery, although it can charge and
release its energy much faster. This is very useful, and that’s
why you will find capacitors used in almost every circuit board. So, how does the capacitor work? I want you to first think of a water pipe with water flowing through it. The water will continue to
flow until we shut the valve, then no water can flow,
however, if after the valve, we first let the water flow into a tank, then the tank will store some of the water but we will continue to get
water flowing out of the pipe. Now when we close the valve, water will stop pouring into the tank but we still get the steady supply of water out until the tank empties. Once the tank is filled again, we can open and close the
valve as many times as we like. As long as we do not
completely empty the tank, we will get an uninterrupted
supply of water out of the end of the pipe. So, we can use a water tank to store water and smooth out
interruptions to the supply. In electrical circuits, the
capacitor acts as the water tank and stores energy. It can release this to
smooth out interruptions to the supply. If we turned a simple
circuit on and off very fast without a capacitor, then
the light will flash, but if we connect a
capacitor into the circuit, then the light will remain
on during the interruptions, at least for a short duration, because the capacitor is now discharging and powering the circuit. Inside a basic capacitor, we have two conductive metal plates, which are typically made
from aluminium or aluminum, and these will be separated by a dielectric insulating
materials such as ceramic. Dielectric means the
material will polarize when in contact with an electric field, and we’ll see what that means shortly. One side of the capacitor is connected to the positive side of the circuit, and the other side is
connected to the negative. On the side of the capacitor, you will see a stripe and a symbol. This will indicate which
side is the negative. If we were to connect a
capacitor to a battery, the voltage will push the electrons from the negative terminal
over to the capacitor. The electrons will build up
on one plate of the capacitor, while the other plate, in
turn, releases some electrons. The electrons can’t pass
through the capacitor because of the insulating material. Eventually, the capacitor is
the same voltage as the battery and no more electrons will flow. There is now a buildup
of electrons on one side. This means we have stored energy and we can release this when needed. Because there are more
electrons on one side compared to the other, and electrons
are negatively charged, this means we have one
side which is negative and one side which is positive, so there is a difference in potential, or a voltage difference, between the two, and we can measure this with a multimeter. Voltage is like pressure. When we measure pressure,
we’re measuring the difference or potential difference
between two points. If you imagine a pressurized water pipe, we can see the pressure
using a pressure gauge. The pressure gauge is comparing
two different points, also: the pressure inside the pipe compared to the atmospheric
pressure outside the pipe. When the tank is empty,
the gauge reads zero because the pressure inside
the tank is now equal to the pressure outside the tank, so the gauge has nothing
to compare against; both are the same pressure. The same with voltage, we’re
comparing the difference between two points. If we measure across a 1.5 volt battery, then we read a difference of
1.5 volts between each end, but if we measure the same
end, then we read zero because there’s no difference
and it’s going to be the same. Coming back to the
capacitor, we measure across and read a voltage
difference between the two because of the buildup of electrons. We still get this reading even when we disconnect the battery. If you remember, with magnets, opposites attract and
pull towards each other. The same occurs with the build-up of negatively charged electrons. They are attracted to the
positively charged particles of their atoms on the opposite plate. They can never reach each other because of the insulating material. This pull between the two
sides is an electric field, which holds electrons in place
until another path is made. If we then place a small
lamp into the circuit, a path now exists for
the electrons to flow and reach the opposite side. So, the electrons will flow
through the lamp, powering it, and the electrons will
reach the other side of the capacitor. This will only last a
short duration, though, until the buildup of electrons
equalizes on each side. Then the voltage is zero. So, there is no pushing force
and no electrons will flow. Once we connect the battery again, the capacitor will begin to charge. This allows us to
interrupt the power supply and the capacitor that will provide power during these interruptions. So, where do we use capacitors? They look a little bit different
but they’re easy to spot. In circuit boards, they tend
to look something like this, and we see them represented
in engineering drawings with symbols like these. We can also get larger capacitors, which are used, for example,
on induction motors, ceiling fans, and air conditioning units. We can get even larger ones, which are used to
correct poor power factor in large buildings. On the side of the capacitor,
we will find two values. These are the capacitance and the voltage. We measure capacitance of
the capacitor in the unit of Farads, which we show with a capital F, although we will usually measure
a capacitor in microfarads. With microfarads, we just
have a symbol before this, which looks something like
a letter U with a tail. The other value is our voltage, which we measure in
volts, with a capital V. On the capacitor, the voltage
value is the maximum voltage which the capacitor can handle. We’ve covered voltage in
detail in a separate video. Do check that out, link’s down below. As I said, the capacitor is rated to handle a certain voltage. If we were to exceed this, then
the capacitor will explode. Let’s have a look at that in slow motion. Eh, pretty cool. So, why do we use capacitors? One of the most common
applications of capacitors in large buildings is for
power factor correction. When too many inductive loads
are placed into a circuit, the current and the voltage
waveforms will fall out of sync with each other and the current
will lag behind the voltage. We then use capacitor
banks to counteract this and bring the two back into alignment. We’ve covered power factor
before in great detail. Do check that out, link’s down below. Another very common application
is to smooth out peaks when converting AC to DC power. When we use a full bridge rectifier, the AC sine wave is flipped to make the negative cycle
flow in a positive direction. This will trick the circuit into thinking it’s getting direct current,
but one of the problems with this method is the
gaps in between the peaks. But as we saw earlier,
we can use a capacitor to release energy into the circuit during these interruptions, and that will smooth the power supply out to look more like a DC supply. We can measure the capacitance and the stored voltage using a multimeter. Not all multimeters have
the capacitance function, but I’ll leave a link down below for the model which I personally use. You should be very
careful with capacitors. As we now know, they store energy and can hold high voltage
values for a long time, even when disconnected from a circuit. To check the voltage, we switch
to DC voltage on our meter, and then we connect the red wire to the positive side of the capacitor and the black wire to the negative side. If we get a reading of
several volts or more, then we should discharge that by safely connecting the
terminals to a resistor and continue to read the voltage. We want to make sure
that it’s reduced down into the millivolts
range before handling it, or else we might get a shock. To measure the capacitance,
we simply switch the meter to the capacitor function. We connect the red wire
to the positive side and the black wire to the negative side. After a short delay, the
meter will give us a reading. We will probably get a reading
close to the stated value but not exact. For example, this one is
rated at 1,000 microfarads, but when we read it, we get
a measurement of around 946. This one is rated at 33 microfarads, but we measure it, we get around 36. Okay, guys, that’s it for this video, but to continue your learning, then check out one of
the videos on-screen now and I’ll catch you there
for the next lesson. Don’t forget to follow us on
Facebook, Twitter, Instagram, and of course, TheEngineeringMindset.com.
president moon jane says that once the
nation semiconductor industry is fully propped up with a steady supply chain of
components and equipment it will become the world’s greatest semiconductor power
visiting a completion ceremony for a new production line at M EMC Korea’s
electronic components Factory in Tallinn the president again promised to support
the semiconductor business M EMC Korea which is owned by Taiwanese firm global
wafers the world’s third largest silicon wafer manufacturer produces key
materials for semiconductor chips and global wafers recently announced it will
invest over 400 million u.s. dollars in new production facilities at the tonin
plant by the year 2020
The modern world depends on electricity. It’s not just a luxury we use to power our
devices and enjoy our free time. It’s not even just a convenience of having
light, heating, and cooling in our buildings. Electricity is a crucial resource, especially
in urban areas, providing public security, safety, and health and making possible everything
from emergency response to modern medical care in hospitals to even the other utilities
we require like fresh water and sanitation systems. But unlike those other utilities, electricity
can’t be created, stored, and provided at a later time. The instant it’s produced, it’s used no
matter how far apart the producer is from the user. And the infrastructure that makes all this
possible is one of humanity’s most important and fascinating engineering achievements. Hey I’m Grady and this is Practical Engineering. Today we’re talking about the power grid. This video is sponsored by NordVPN. Visit NordVPN.com/practicalengineering to
get 75% off a 3-year plan. More on that later! Like most people, you probably take the grid
for granted. Electrical infrastructure is so ubiquitous,
it’s easy not to notice that the majority of our power grid is out in the open for anyone
who wants to have a look. I happen to be one of those people who does
want to have a look, and hopefully by the end of this video series on electrical infrastructure,
you will be too. This video is geared toward North America,
but most of the concepts will apply to any other part of the world. And just to give you a sense of scale, there
are only four distinct electrical grids that service essentially all of North America. You have the two big ones, Western and Eastern,
and the two electrical separatists: Quebec and Texas. Depending on your definition, an electrical
grid can be considered one of the world’s largest machines. So how does this machine work? The basic function of generating electricity
and delivering it to those who need it may seem simple. I can hook up a small generator to a light,
and boom; electrical grid. With the cost of solar panels reaching record
lows, many are exploring the possibility of generating all the power they need at home
and forgoing the grid altogether. But, a wide area interconnection (that’s
the technical term for a power grid) offers some serious advantages in exchange for increased
complexity. Here’s a simplified diagram showing the
major components of a typical power grid, and we’ll follow the flow of electrical
current as it makes its way through each one. We start with generation, where the electricity
is produced. There are many types of power plants, each
with their own distinct advantages and disadvantages, but they all have one thing in common: they
take one kind of energy and convert it into electrical energy. Most power plants are located away from populated
areas, so that electricity they create needs to be efficiently transported. That’s handled by high-voltage transmission
lines. At the plant, transformers boost the voltage
to minimize losses within the lines as the electricity makes its way to the areas that
need it. Once it reaches populated areas, transformers
then step down the power back to a safer and more practical voltage. This is done at a substation, which also has
equipment to regulate the quality of the electricity and breakers to isolate potential faults. Some energy customers draw power directly
from transmission lines, but most are served from feeder lines that carry power from the
substation. This part of the system is called distribution. From the feeders, smaller transformers step
down voltage to its final level for industrial, commercial, or residential uses before the
electricity reaches its final destination. Rather than a constant flow of current in
a single direction (called direct current or DC), the vast majority of the power grid
uses alternating current or AC, where the direction of voltage and current are constantly
switching, 60 times per second in North America. The major advantage of AC power is that it’s
easy to step up and down voltages, a critical part of efficiently and safely moving electricity
from producer to consumer. The device that performs this important role,
called a transformer, is as simple as a pair of coils next to each other. A varying voltage in one coil induces a voltage
in the other coil proportional to the number of turns in each one. If the current doesn’t vary, like in direct
current, the transformer can’t do any transforming. It’s helpful to think about the grid as
a marketplace. Power producers bring their electricity to
the market by connecting to the grid, and power consumers purchase that electricity
for use in their home or business. The economics and politics of the grid are
so much more complicated than this, but the important part of the analogy is that, in
many ways, the power grid is a shared resource. Because of that, it needs organizations to
oversee and establish rules about how each participant in the producing, transmitting,
and consuming of power may use it. And there are three overarching technical
goals that engineers use to design and maintain the power grid. The first one is power quality. Our electrical devices and equipment are designed
assuming that the power coming from grid has certain parameters, mainly that the voltage
and frequency are correct and stable. Some devices count the oscillations in the
AC grid power to keep track of time, so it’s critical that the grid frequency not deviate. Changes in the voltage can lead to brownouts
or surges that damage connected equipment. One of the benefits of a large power grid
is electrical inertia. All those huge spinning generators connected
together provide momentum that smooths out the ripples and spikes that can occur from
equipment faults or quickly changing electrical loads. The next technical goal of the grid is reliability. If, like most people, you take that constant
availability of power for granted, that’s by design. Much of the grid’s complexity comes from
how we manage faults and provide redundancy so that you’re rarely faced with blackout
conditions. It’s another inherent benefit of a grid
that electricity can be rerouted when a piece of equipment is out-of-service, whether it
was planned or otherwise. The final goal of the power grid is simply
that the supply meet the demand. Power production and consumption happens on
a real-time basis. If it’s plugged in, the light from the screen
you’re watching right now was a drop of water in a turbine or a breeze across a windmill
microseconds ago. And by the way, did you call your utility
and let them know that you were going to turn on your computer or phone and watch this video? I’m willing to bet you didn’t, which means
not only did they have to adjust their production up to match the extra load, but they had to
do it immediately without any warning whatsoever. Luckily having millions of people connected
to the same grid smooths out the demands created by individuals, but load following is still
a major challenge. For the most part, electrical demand follows
a fairly consistent pattern, but factors like extreme weather can make it difficult to forecast. Grid operators balance demand by dispatching
generation capacity in real time. The cheapest sources of power are used to
fulfill the base load that’s more consistent, and higher cost sources are used for peaking
when demand exceeds the base. But it’s not as simple as flipping on a
switch. Large power plants can take hours, days, or
even weeks to startup and shut down. Equipment needs to be taken out of service
for maintenance. Fuel costs fluctuate. Renewable sources like wind and solar can
have massive and unpredictable variations in capacity, providing irregular sloshes of
power to the grid. You can see why balancing electricity supply
and demand is this fantastically complex job of taking into account all these considerations,
some of which are predictable and some of which aren’t. That’s part of the reason we are trying
to make the grid smarter by using software, sensors, and devices capable of communicating
with each other. On the supply side, this can allow computers
and software to do what they do best: take in tremendous amounts of data to help us make
decisions about how to manage the grid. But a smart grid can also help on the demand
side as well. Unlike most of the goods we buy, consumers
don’t have a keen understanding of power, how much we’re using, or how much it should
cost depending on the time of day or year. A smart grid can take away some of the obfuscation,
allowing us to make better decisions about how we use electricity in our day-to-day lives. Ultimately, a smart grid can help us use and
take care of this huge machine – this shared resource we call the power grid – more efficiently
and effectively now and into the future. Just like electricity, internet connectivity
is a resource on which we depend more and more. I work on these videos in my spare time, which
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What legal regime applies to a situation of occupation? As emphasized by Professor Bothe, three main principles govern the law of occupation. Firstly, occupation – which must remain temporary – does not entail a transferal of sovereignty to the occupying power. Secondly, the occupying power has a duty of good governance for the duration of the occupation. Thirdly, the occupying power may take measures that are necessary to ensure the protection of its own interests and security. Let’s briefly examine these three principles. It flows from the first rule on continuity of sovereignty – which can be found in Article 43 of the Hague Regulations – that the occupying power must leave unchanged pre-existing laws and institutions of the occupied territory, except where the occupying power is “absolutely prevented” from doing so. Indeed, the occupying power is considered to be a transitional authority, which does not assume sovereign power. This principle can also be deduced from Article 64(1) of Geneva Convention IV, which Article 64 (1) states that “(t)he penal laws of the occupied territory shall remain in force”. However, paragraph (2) of this provision contains three broad exceptions to the principle of continuity, allowing the occupying power to subject the population to provisions which are essential to enable this power: firstly, to fulfil the obligations under Geneva Convention IV; secondly, to maintain the orderly government of the occupied territory; or thirdly, to ensure security of the occupying power. We will briefly get back to these caveats in a minute. It should also be underlined that Article 47 of Geneva Convention IV reinforces the principle of continuity by depriving any measures that would result in a change of status of the occupied territory from having legal effect. An example of such a measure would be an attempt to annex the territory. Article 54(1) of Geneva Convention IV guarantees the principle of continuity at both administrative and judicial levels by prohibiting altering the status of public officials or judges, applying sanctions or taking coercive or discriminatory measures against them. Regarding the duty of good governance imposed upon the occupier, it is important to recall that, according to Article 43 of the Hague Regulations, the occupying power has the duty to restore and ensure public order and safety. This duty is further specified by concrete obligations contained in both the Hague Regulations and Geneva Convention IV aiming at ensuring the well-being of the population. It implies, amongst other things, that the occupying power must: respect the fundamental rights of the population under occupation; provide the population with adequate living conditions, including food, health care, education, medical supplies and clothing; guarantee the maintenance and, if necessary, the development of an adequate legal order and administrative apparatus; respect private property; protect family rights; and provide a functioning court system, which does not violate the rule of law. The respect of these obligations will be particularly important for long-term occupation, which will often require adapting existing norms or institutions to the changing needs of the local population. For instance, in order to ensure the effective administration of justice, the occupying power may engage structural reforms and, for instance, re-establish the judiciary when the judicial system has been broken down during the hostilities. It is important to note that fundamental rights, which must be respected by the occupying power, are contained, not only in the Hague Regulations and in Geneva Convention IV (in particular, in Article 27 of this Convention), but also in Human Rights instruments, including instruments of both a general and specific nature. The third rule allows the occupying power to take law-enforcement measures that are necessary to ensure the protection of its security interests – including interning members of the civilian population under certain strict conditions – unless there is a situation of armed conflict (which may require the use of force). In order to ensure the sustenance of the occupying army, two measures can be taken: requisitions in kind or services as a matter of principle against compensation (as envisaged in Article 52 of the Hague Regulations) and, under certain conditions, money contributions (as envisaged in Article 49 of the Hague Regulations).