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Bryan Underwood Advisor: Prof. Gutschlag

Bryan Underwood Advisor: Prof. Gutschlag. Alternating Current Power Factor Monitoring and Correction. Power Factor. Power Factor is the ratio of the active power to the apparent power P.F. = =. Complex Power Diagram. Power Factor (cont.).

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Bryan Underwood Advisor: Prof. Gutschlag

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  1. Bryan Underwood Advisor: Prof. Gutschlag Alternating Current Power Factor Monitoring and Correction

  2. Power Factor Power Factor is the ratio of the active power to the apparent power P.F. = = Complex Power Diagram

  3. Power Factor (cont.) • Poor power factor is due to inductive loads such as induction motors in air conditioners and refrigerators • A very low power factor usually results in the power company charging more on a utility bill

  4. Standards • Ameren Illinois requires Residential customers (rate DS-1) and Light Industrial Non-Residential customers (rate DS-2, DS-3) to maintain a power factor of 0.90 while Heavy Industrial Non-Residential customers (rate DS-4) must maintain a power factor of 0.951

  5. Power Company Charges • If the power factor falls below the minimum specified by Ameren and ComEd, they require corrective devices to be installed • Pacific Gas and Electric (PG&E) charges 0.6% more on a utility bill for each percentage point below a power factor of 0.852

  6. Industry Averages • About 60% of the electrical load in the United States is due to AC electric motors3 • According to the U.S. Energy Information Administration (EIA), only about 25,000 out of 200,000 manufacturing companies participate in power factor correction (PFC)4

  7. Reasons for Power Company Surcharges or Requirements for Power Factor Improvement • Increased I2R losses in transmission lines due to the additional current requirements needed to provide excess reactive power reduces efficiency, capacity, and profit margins • Increased current requirements result in higher transmission line, transformer, and switch gear current ratings

  8. Power Factor Correction (PFC) http://accessscience.com/content/Reactive-power/802370 • Usually done by capacitor banks • Generate “negative” reactive power

  9. Equipment Hampden Type WRM-100 3-Phase Motor • 220 V • 1.4 A • 1725 RPM • 1/3 HP

  10. Motor Efficiency and Power Factor

  11. Equipment (cont.) SATEC PM172E-N 3-Phase Programmable Power Meter

  12. Software • SATEC Power Analysis Software V1.4 Build 5 • Configure basic setup of meter, set trigger points, and view event logs and waveforms

  13. Alternative Meters • Larger meters have more relay inputs and outputs to permit more incremental values of capacitors to be switched as needed for more precise control of the power factor • More programming options provide more robust control for better power factor correction directindustry.com news.thomasnet.com

  14. Relays Potter & Brunfield KRPA-11AG-120 Power Relays

  15. Capacitor Banks • Capacitance is added to each line and can be varied from 1.6uF to 50uF

  16. Damping Resistors • Resistors are placed in series with the capacitor banks to reduce inrush currents

  17. Damping Resistors Loses • Current through resistor with 10uF Capacitor • Power losses • Current w/ 20uF • Power losses • Current w/ 30uF • Power losses

  18. System Diagram

  19. System

  20. Capacitor Bank Switching • Relay coils are energized from SATEC meter when the power factor drops below a certain point • Line current is also monitored to ensure no switching occurs when no load is present • Capacitors are added to the circuit in parallel with the motor • Placed in parallel to maintain the same line voltages into the motor • Power factor can be varied over any desired range to avoid electric utility company charges • Project system maintains a power factor of above 0.98

  21. Flow Chart

  22. Experimental Results -0.9

  23. What’s Next? • Complete the theoretical circuit model and compare with experimental results • Research how the meter calculates its values • Write tutorial on how to use power meter • Will use as an appendix for final paper • Write final paper

  24. Questions?

  25. References 1 http://www.ameren.com/sites/aiu/Rates/Documents/AIel14rtds4.pdf http://www.ameren.com/sites/aiu/Rates/Documents/AIel48rdimf.pdf 2 http://www.pge.com/includes/docs/pdfs/mybusiness/customerservice/energystatus/powerquality/power%20factor--revised-8-9-07.pdf 3http://www.pge.com/includes/docs/pdfs/mybusiness/customerservice/energystatus/powerquality/power%20factor--revised-8-9-07.pdf 4 http://www.eia.gov/emeu/mecs/mecs2002/data02/excel/table8.1_02.xls

  26. System Values at Various Loads

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