Powsys may2008


Published on

  • Be the first to comment

  • Be the first to like this

No Downloads
Total views
On SlideShare
From Embeds
Number of Embeds
Embeds 0
No embeds

No notes for slide

Powsys may2008

  1. 1. An Introduction toElectric Power Plants Jeffrey R. Regester
  2. 2. In order to understand this...
  3. 3. Outline• E&M Principles• Types of Power Plants• Power System Components
  4. 4. Principles• energy = “the ability to do work” measured in Joules• power = rate of energy generation or use measured in Watts = Joules / sec• current = rate of charge flow measured in Amps Water pipes analogy• voltage = “pressure” pushing current measured in Volts
  5. 5. Moving Electrons Create Magnetic Fields • electromagnetsDEMO: electromagnet & compass on overhead
  6. 6. Magnetic Fields Push on Moving Electrons or moving magnetic fields push on stationary electrons • generators • speakersDEMO: force on current apparatusDEMO: make current with magnet & coil
  7. 7. The Purpose of a Power Plant is to Turn a Loop of Wire in a Magnetic Field Why do we need “mechanical means”? It takes a force to push a conductor through a magnetic field — inertia won’t due. Car alternator...DEMO: copper tubeDEMO: GeneconsDEMO: Al plate and mag
  8. 8. Powerhouse @ Hoover Dam
  9. 9. Types of Power PlantsClassification by the “mechanical means” used to turn the generator...• Thermal (water steam by burning Coal, Oil, NG)• Nuclear (water steam by Uranium or Plutonium fission)• Geothermal• Hydroelectric (falling water)• Wind Solar...
  10. 10. Thermal Power Plant
  11. 11. Nuclear Power Plant
  12. 12. Hydroelectric Power Plant
  13. 13. Hoover Itaipu
  14. 14. Power Plant ComponentsELECTRICAL MECHANICAL• Generators & Turbines • Conveyors• Transformers • Silos• Switches • Boilers• Busses • Scrubbers & Stacks• Circuit Breakers • Pumps• Capacitor Banks • Cooling Towers
  15. 15. At the front end• Conveyors• Boilers• Scrubbers and Stacks• Pumps• Cooling Towers
  16. 16. Generators• The whole point of the power plant is to turn the generators to produce electrical energy.
  17. 17. Turbines• Difficult to replace• A spare is often kept
  18. 18. Busses• uninsulated electrical conductors• large cross-section = low resistance• must be far from ground and other components to avoid arcing flirthermography.com
  19. 19. Switches & Switchyards http://www.learnz.org.nz/trips06/images/big/b-switchyard.jpg
  20. 20. Transformers• PURPOSE: to change the voltage – increase = “step-up” – decrease = “step-down”• Often run hot, must be cooled, prone to explode. – oil inside – cooling fins and fans – blast walls DEMO: pass around small transformer DEMO: two coils, one with meter, other with battery
  21. 21. Circuit Breakers• PURPOSE: stop the flow of current if too much flows (due to short circuit or excess demand) DEMO: blow room breaker 230 kV breaker
  22. 22. Capacitor Banks • Purpose: to smooth out spikes or “glitches” in the line voltage.DEMO:charge/discharge a capDEMO:Lenz’s Law
  23. 23. Transmission Lines and the “grid”
  24. 24. Why are High Voltages Used?• Transmission lines typically • And why is that so? carry voltages of 110 kV, 230 Transformers cannot add kV, or even higher. The wires energy, so if the voltage is are not insulated, so they are increased, the current (in amps) kept high off the ground and must decrease. The charges well separated from each other, flowing through the wires to prevent arcing (sparks) and constantly collide with the injury or people or animals. atoms, losing energy and heating the wire. We call this• resistance. Recall that the Why use such high voltages? power (energy per time) lost to Using very high voltages on the that heating is given by the transmission lines reduces the equation P=I2R. If the current is amount of energy wasted reduced, the power used in heating up the wires. heating the wire is reduced.
  25. 25. Transformer Sub-Station Purpose: • to reduce the very high voltages from the transmission lines (>100kV) to intermediate voltages used to serve an individual TTR Substations, Inc. town or section of a city (typically 66 kV or 33 kV)
  26. 26. To your house... smaller transformers (on power line poles or green boxes on the ground) reduce the voltage further to the 240V delivered to individual homes