Exploring the Energy Grid Grades 6-8. Name:

Transcription

1 Exploring the Energy Grid Grades 6-8 Name: Exploration 1 Rapidly turn the handles clockwise on all three generators at the end of the table, watching the System Voltage panel: 1. Draw the needle when the light is in the GREEN range: 2. Write the number when the light is in the GREEN range: 1

2 Discussion 1 In 1831 Michael Faraday discovered one of the fundamental principles of electromagnetism. It is called Faraday s Law. His law explains how electricity and magnetism interact, and forms the basis for modern electric motors and generators. Electric generators convert kinetic (motion) energy into electrical energy. 1. Explain how the generator is producing electricity. (Use the generator to determine its working parts and read the diagram on the side of the grid table.) 2. If you connected a generator to the pedals of a bicycle, do you think you could power your house? Why or why not? 3. Use the diagram on the side of the table to help you draw a line to connect the parts of a generator to i s name: Hand crank Drive belt Stator Rotor Commutator Brushes Output terminals 2

3 Exploration 2 Make sure the Smart Grid Enable Switch is off and use the Smart Grid Table Wiring Directions located on the table to connect the power companies to the customers. 1. After you wire the table, describe what happens to the buildings and System Voltage when you turn the three hand crank generators: 2. In the real world, the voltage on the electric grid must be maintained within a very narrow range. In this model electric grid, the voltage must be maintained at approximately Volts in order to keep the customers lights on. What happens when you use only one generator? 3. Flip the bypass switch on the back of the SmartGrid switch so you don t have to use the generators to power the houses. Disconnect any one wire. Describe which wire you disconnected and how it affected the buildings: 4. Leave the wire disconnected and turn ON the Smart Grid Switch. Describe what happens to the Smart Grid panel and the buildings: 5. Can you wire the grid so that ONLY: House #1, Farm, and Apartment #1 are lit? Describe what the Smart Grid panel looks like in relation to the buildings when you do this: 3

4 Discussion 2 1. What do the green lights on the Smart Grid Control Panel indicate? 2. What do the red lights on the Smart Grid Control Panel indicate? 3. How do you think utility companies with standard meters (no Smart Grid) find out if a wire is broken or disconnected? 4. How do utility companies with Smart meters (with Smart Grid) find out if a wire is broken or disconnected? Reconnect all the buildings to the grid after you finish answering the discussion questions. Apply It! Sometimes electricity goes off because of storm damage to transmission lines. 1. Has the electricity ever gone off at your home? 2. How long was it off? Turn the Smart Grid Switch OFF A storm hit your area causing the power to go out in your neighborhood. Ask your teacher (or someone else) to cause a problem in your grid. 3. Keeping the SmartGrid off, describe how you found and fixed the problems: Turn Smart Grid Switch ON Another storm hit your neighborhood. Ask your teacher (or someone else) to cause problem in your grid. 4. With the SmartGrid on, describe how you found and fixed the problems: 5. How do you think the Smart Grid help utility companies? 6. How do you think the Smart Grid help customers? 4

5 Expanding Although in this table-top simulation the voltage remains low and fairly constant over the entire grid, in real electric grids that is not the case. Photo credit: Angelsharum, Wikimedia Commons, CC BY-SA 3.0 Electrical power coming out of a real generator is at a fairly low voltage. Low voltage is not very efficient for transmission over large distances, so the voltage has to be stepped up. When it gets to your city, it has to be stepped down because very high voltage would be too dangerous for household use. Besides describing generators, Faraday s Law can be used to describe transformers. A transformer is used to change voltage in an electrical system. It has two coils of wire that are wrapped around a core, which is typically iron. When electricity flows in one coil, it induces electricity to flow in the other. The side that has more turns (loops) of wire has the higher voltage. In this way, voltage can be stepped up for long-distance transmission, and stepped down for distribution in neighborhoods. Primary coil (or primary winding ) This is the side where the electricity goes in Secondary coil (or secondary winding ) This is the output 5

6 1. Why must the voltage of the electricity coming out of the power plant be stepped up? 2. In a step up transformer, which side has more wire, the primary coil or the secondary coil? 3. In a step down transformer, which side has more wire, the primary coil or the secondary coil? 4. If the output of a step up transformer has double the input voltage, how would you expect the lengths of wire in the primary and secondary coils to compare? Label the following diagram: 6