1. © 2010 Board of Regents University of Nebraska The History of Electricity

2. © 2010 Board of Regents University of Nebraska Electrical Discoveries Natural occurrences of electricity: Lightning Static-amber rods rubbed with cat fur Electric fish (electric eels, electric catfish, others) Nerve operation Brain activity

3. © 2010 Board of Regents University of Nebraska Electrical Discoveries Numerous scientists from 1600’s on started treating this as more than a curiosity Benjamin Franklin’s kite experiment in 1752 proved lightning was electricity Luigi Galvani in 1791 proved that electricity is what makes nerves work

4. Ben Franklin © 2010 Board of Regents University of Nebraska

5. Electrical Inventions Electromagnetism united electricity and magnetism in 1819 (Orsted and Ampere) Faraday invented the electric motor in 1821 1830’s: several inventors created the telegraph Alexander Graham Bell invented the telephone in 1876 Thomas Edison invented the electric light bulb in 1879 Nikola Tesla invented Alternating Current

6. Thomas Edison © 2010 Board of Regents University of Nebraska

7. Nikola Tesla © 2010 Board of Regents University of Nebraska

8. Electrical Inventions Whale oil, “town gas”, kerosene primary means of providing gas lights for many years prior to electricity Widespread use of electricity to operate lights Batteries Electric vehicles Enhanced and larger electric motors: AC and DC Large generating systems: AC and DC

9. © 2010 Board of Regents University of Nebraska The Industrial Revolution 2 nd half of the 1700’s through the 1800’s Mechanization transformed modern society Large industries sprang up, many powered by horses, then by steam engines Agrarian farm life rapidly declined as farmers went to work in factories to earn better wages Textiles, iron manufacturing, invention of concrete, all spurred growth in industrial systems

10. © 2010 Board of Regents University of Nebraska The Industrial Revolution Prior to steam power, horse power and water power were the dominant forms of primary power for industry Most fast-moving water was in New England states Development of steam power opened up other areas of US for industrial development Transportation changed dramatically thanks to steam- powered trains

11. Steam Locomotive © 2010 Board of Regents University of Nebraska

12. The War of the Currents: AC vs. DC Edison promoted his Direct Current(DC) as the only “safe” way to deliver electricity to large populations Westinghouse promoted Alternating Current (AC) as the only way to transport electricity over long distances DC commercial power canonly be transported a few miles. Edison invented large scale DC generators Westinghouse bought patents for AC from Tesla

13. George Westinghouse © 2010 Board of Regents University of Nebraska

14. The War of the Currents: AC vs. DC Edison started General Electric, later lost it to bankers 1882: Edison builds Pearl Street DC station in NYC 1894: Niagra Falls Power Company powered Buffalo, NY Westinghouse/Tesla team eventually won the war of the currents Today AC electricity can be transported 1000’s of miles by increasing the voltage at the generator to extreme levels

15. © 2010 Board of Regents University of Nebraska Electrical Distribution Begins Various frequencies of AC were tried. Settled on 60Hz 60Hz was used because of easy timing with clocks. Also any frequency above about 40-50Hz makes flicker- free lighting: important in AC systems Also higher frequencies would require faster spinning generators, creating mechanical challenges 1893: Westinghouse/Tesla system demonstrated AC at Chicago Exposition

16. © 2010 Board of Regents University of Nebraska 1900’s: Electrical Distribution Begins Once an electrical power generating systems begins, all generators tied to that “grid” must be same frequency and phase When loads increase demand for electricity, more generators must be added. Numerous safeguards must be built in for safety and isolation of failures First distribution systems were in cities where it was economical for the electric utilities to build and sell power to large customer bases

17. © 2010 Board of Regents University of Nebraska REA and TVA Rural Electrification Administration Tennessee Valley Authority Great Depression of 1929 Public power vs. private (investor-owned) utilities hotly contested during 1920’s

18. © 2010 Board of Regents University of Nebraska REA and TVA Prior to 1933, privately owned utilities refused to extend their service to rural areas, claiming lack of profitability Private power companies set rural rates 4 times higher than city rates Obviously, this was not perceived as a fair treatment of rural families

19. © 2010 Board of Regents University of Nebraska TVA Tennessee Valley Authority Federally-owned private corporation Established in May 1933 to provide: Flood control Navigation of waterways Affordable electricity for rural communities Fertilizer for more effective, productive farming Economic development

20. © 2010 Board of Regents University of Nebraska TVA Cover s most of Tennessee, parts of Alabama, Mississippi, Kentucky, a few other SE States. Nation’s largest public power company FDR campaigned on this issue during Presidential race: 1932 Nebraska Senator George Norris from McCook, NE partnered with Franklin Roosevelt to help establish public power entities Red=dams; purple=nuclear power; yellow=fossil power

21. © 2010 Board of Regents University of Nebraska

22. REA Rural Electrification Administration established 1935 Made loans available to local electric cooperatives to compete with big power companies 1930: 10% of rural homes had electricity 1940: 90% of rural homes had electricity

23. © 2010 Board of Regents University of Nebraska REA PUHCA (Public Utility Holding Company Act): 1935 Regulate electric utilities Get control of private utilities REA has been reorganized (1994) and is now called RUS (Rural Utilities Service) RUS is an agency of the United States Dept of Agriculture RUS Tasked with providing to rural areas the following utilities: Electricity Telephone Water Sewer

24. © 2010 Board of Regents University of Nebraska US Electrical Distribution Today Three separate grids: Eastern interconnection Western interconnection Texas interconnection (ERCOT: Electric Reliability Council of Texas) Alaskan and some Canadian grids separate from the three main USA grids

25. © 2010 Board of Regents University of Nebraska

26. US Electrical Distribution Today Reliability of each grid is critical Each grid started independently at different times Very little interconnection between the three grids 60 Hz phase is different in each grid Can not directly connect grids together Must convert 60Hz AC to DC, then back to AC at the receiving grid’s phase

27. © 2010 Board of Regents University of Nebraska US Electrical Distribution Today Utility generators create 2300 to 30,000 volts A transformer steps this voltage up to a higher voltage for long- distance transmission When voltage is stepped up, current is stepped down Some power is lost in the transformation of voltage/current Numerous high voltage systems in use across North America 765,000 volts 500,000 volts345,000 volts230,000 volts 138,000 volts 115,000 volts

28. © 2010 Board of Regents University of Nebraska US Electrical Distribution Today At various locations, sub-stations reduce the transmission voltage to more usable levels 4000 volts – 69,000 volts Final users get their power at lower voltages of 120-480 volts. Transformers are used to change voltage levels, up and down. Only AC power can do this

29. Electrical Distribution System © 2010 Board of Regents University of Nebraska