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Title
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The Power Grid
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Type
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Primary: Mission Briefing Article
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Operation
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Infinite Potential
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Mission:
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Mission 3: Power to the People
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Print Page
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60,61
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Subjects
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Physical science | Electricity | Science and technology | Energy technology | Science
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Grades
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5 | 6 | 7 | 8
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Keywords
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electricity, power plant, power distribution grid, energy, electrical energy, power, alternating current, 120-V 60-cycle AC power, volt, voltage, transformer, transmission, transmit, distribution, fuse, circuit breaker, ground fault circuit interrupter, GFCI, leak, brownout, blackout, brown out, black out
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Duration
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00:15:00 (HH:MM:SS)
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Audience
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Teachers | Elementary Grades | Junior High
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Created On
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4/13/2009
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Copyright
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Nuclear power plant photo: Marya/Wikimedia Commons; Team Highlight photo: Peter Haydock, The JASON Project
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From: Infinite Potential Mission 3: Power to the People (pp: 60,61) |
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The Power Grid How does a power plant get electricity to your house and what safety features are in place? Find out all about power plants in this article. |
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   The electrical energy produced at a power plant travels to your house through the power distribution grid. The power distribution grid is a system of facilities and structures that provide an organized and efficient way to deliver energy from the power plant to all of the people and things that need it. The diagram on this page illustrates how the power distribution grid works in North America. The power that comes from a power plant in the United States is alternating current. The direction of the current alternates 60 times per second. The main advantage of alternating current within the grid is that it provides a relatively easy way to change the voltage of the power using a device called a transformer. Transformers allow power companies to convert current electricity to very high voltages for transmission across power lines, then drop it back down to lower voltages for distribution and typical home use. The power that is available on transmission lines can reach 765,000 volts. The power that is available from a wall socket in the United States is 120-volt AC power. On occasion, the power grid can experience brownouts or blackouts that disrupt power. A brownout is a temporary reduction in power, whereas a blackout is a temporary loss of power altogether. Brownouts and blackouts can occur due to grid damage caused by things such as storms. In other instances, a power company will actually decrease the supply of power due to excess demand. Safety Features
Throughout the power distribution grid and in your own home, there are many key safety features to protect you. Fuses or circuit breakers can prevent fires. A fuse is a thin piece of wire that melts when too much current is sent through it, thereby breaking the circuit and stopping the current from flowing. A circuit breaker is a switch designed to automatically shut off when a circuit becomes overloaded. Meanwhile, a ground fault circuit interrupter (GFCI) outlet continually detects how much electric current is flowing. It shuts off the power whenever it detects any “leak” in the circuit that could cause an electrocution.
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