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The Power Grid


The power grid is the system of producers and consumers of electricity. It includes power generators, the users of electricity, switches that control the electricity, and the system of substations, power lines, and transformers that deliver the electricity. A community might have a generator to provide its power. The generator may be able to vary its production as the usage of the customers changes, but there may be times when the demand for energy is too great for the generator. Then the community buys electricity from another source. At other times, the generator may be making more electricity than the community is using, so it wants to sell it.

  1. When the applet opens, are the generators making more or less power than the communities are using?
  2. Reset the system and notice the line leading from Substation 5 to Commerceton. How much power is this line carrying? Click on the up arrow to increase Commerceton's power demand. What happens to the arrows on the line? At what load do the arrows change to orange? What color are the arrows when the demand is 1000 MW? What happens when the load on the line is increased again? How can you fix it?
  3. Reset the system, put the nuclear power plant online, and then increase the power demanded by Residenceburg to 1850 MW. What's causing a problem? Reduce the potentially dangerous line overload without taking the nuclear plant offline?
  4. It's a hot summer day and power demand in Residenceburg is 1600 MW. Commerceton is demanding 850 MW, and Industryville needs 800 MW. Put all of your generators online at maximum capacity. Are all of your lines operating safely? Are you able to produce enough power to meet the demand, or do you need to get power from the external system?
  5. Reset the system, turn on the nuclear power plant, and then open the line between substations 1 and 2. What happens? What is the problem? Fix it by changing one switch?
  • Quick-Start Guide: Use this quick-start guide to learn about the features of this applet.
  • Lesson.pdf: Lessons have been created to help you use this applet in your classroom.
  • Lesson.docx: Lessons are available as word documents as well.