![]() Typical voltages for long distance transmission are in the You can see at the back several three-wire towers leaving the Voltages for long-distance transmission on the transmission grid. (which is at the thousands of volts level) up to extremely high This substation uses large transformers to convert the generator's voltage The three-phase power leaves the generator and enters a transmission substation at the power plant. The dirt, rocks, groundwater, etc., of the earth. "the ground" that's all around you when you are walking outside. The car's body.) "Ground" in the power distribution grid is literally Similar they use the metal body of the car as one of the wires in theĬar's electrical system and attach the negative pole of the battery to The earth is a pretty good conductor and it is huge, so it Improve things but would add a fourth wire, so 3-phase is the naturalĪnd what about this "ground," as mentioned above? The powerĬompany essentially uses the earth as one of the wires in the power Industrial applications) and things like 3-phase welding equipment In 3-phase power, at any given moment one of the Why three phases? Why not one or two or four? In 1-phase andĢ-phase power, there are 120 moments per second when a sine wave isĬrossing zero volts. It is simply three single phases synchronized and offset by 120 degrees. There is nothing magical about three-phase power. If you were to look at the three phases on a graph, they would look like this relative to ground: There are four wires coming out of every power plant: the three phases plus a neutral or ground common to all three. The power plant produces three different phases of AC power simultaneously, and the three phases are offset 120 degrees from each other. You'll learn about the AC power produced at the power plant. It is easy to convert AC to DC but expensive to convert DC toĪC, so if you were going to pick one or the other AC would be the.Transformers must have alternating current to operate, and we will see that the power distribution grid depends on transformers.Large electrical generators happen to generate AC naturally, so conversion to DC would involve an extra step.Produce DC: A steady stream of electrons flows in one direction only,įrom the negative to the positive terminal of the battery.ĪC has at least three advantages over DC in a power distribution grid: The alternative to AC is DC, or direct current. Referred to as AC, or alternating current. Like a sine wave, and that wave oscillates between -170 voltsĪnd 170 volts (the peaks are indeed at 170 volts it is the effective House, what you will find is that the power at the wall plate looks Talk about household electrical service as single-phase, 120-volt ACĪnd look at the power found at a normal wall-plate outlet in your Single-phase power is what you have in your house. To understand 3-phase AC power, it is helpful to understand single-phase power first. No matter what it is that spins the generator, commercial electrical generators of any size generate what is called 3-phase AC power. Or the steam may come from a nuclear reactor like this one at the Shearon Harris nuclear power plant near Raleigh, North Carolina: The steam might be created by burning coal, oil or natural gas. But in most cases, the thing spinning the generator is a steam turbine. Something has to spin that generator - it might be a water wheel in a hydroelectric dam, a large diesel engine or a gas turbine. In almost all cases, the power plant consists of a spinning electrical generator. Power grid, you will be able to really see it and understand what isĮlectrical power starts at the power plant. In this article, we will look at all of the equipment thatīrings electrical power to your home. Likely ignores all of the power lines because it has seen them so Public, in fact, that you probably don't even notice it anymore. The grid is quite public - if you live in a suburban or rural area,Ĭhances are it is right out in the open for all to see. Power travels from the power plant to your house through an amazing system called the power distribution grid. Without it, life can get somewhat cumbersome. Light, sound, computation, entertainment. Use it for heating, cooling, cooking, refrigeration, Switch, that you realize how important power is in your daily life. ![]() When you walk into a dark room and instinctively hit the useless light Really think about it until it is missing. Electrical power is a little bit like the air you breathe: You don't ![]()
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